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Background Homo sapiens have experienced admixture many times in the last few thousand years. To examine how admixture affects local adaptation, we investigated genomes of modern Polynesians, who are shaped through admixture between Austronesian-speaking people from Southeast Asia (Asian-related ancestors) and indigenous people in Near Oceania (Papuan-related ancestors). Methods In this study local ancestry was estimated across the genome in Polynesians (23 Tongan subjects) to find the candidate regions of admixture-enabled selection contributed by Papuan-related ancestors. Results The mean proportion of Papuan-related ancestry across the Polynesian genome was estimated as 24.6% (SD = 8.63%), and two genomic regions, the extended major histocompatibility complex (xMHC) region on chromosome 6 and the ATP-binding cassette transporter sub-family C member 11 (ABCC11) gene on chromosome 16, showed proportions of Papuan-related ancestry more than 5 SD greater than the mean (> 67.8%). The coalescent simulation under the assumption of selective neutrality suggested that such signals of Papuan-related ancestry enrichment were caused by positive selection after admixture (false discovery rate = 0.045). The ABCC11 harbors a nonsynonymous SNP, rs17822931, which affects apocrine secretory cell function. The approximate Bayesian computation indicated that, in Polynesian ancestors, a strong positive selection (s = 0.0217) acted on the ancestral allele of rs17822931 derived from Papuan-related ancestors. Conclusions Our results suggest that admixture with Papuan-related ancestors contributed to the rapid local adaptation of Polynesian ancestors. Considering frequent admixture events in human evolution history, the acceleration of local adaptation through admixture should be a common event in humans.

This study examines a Sri Lankan agricultural village community to empirically explore the effects of social and human capital on the resilience of households that are exposed to significant environmental stresses. Data were obtained from a cross-sectional survey of 143 village respondents representing different households in the village community with critical exposure to three environmental stresses: drought, elephant crop raiding, and deprived access to potable water. Structural equation modeling was employed to investigate the relationship between the different dimensions of social and human capital and household resilience measured using subjective assessment scales. The findings indicate that bridging social capital, bonding social capital and economic activeness dimension of human capital significantly predict household resilience in contexts of environmental perturbation.

A chronic kidney disease (CKDu), independent of known causes, such as diabetes and hypertension, is emerging as an epidemic in certain agrarian regions of the developing world. Given the unprecedented incidence of the disease among farm households, in the North Central Province (NCP) of Sri Lanka, CKDu is considered a public health emergency. Ever since the disease was first reported over two and a half decades ago, both local and international research communities have taken significant efforts to reveal the aetiology of the disease. Although the causes of the disease still remain unrevealed, much of the research findings supports a set of environmental and behavioural risk factors that are deemed to be associated with the occurrence and progression of the disease. To encourage healthy behaviours such as consumption of safe, uncontaminated water that minimise the deemed risk factors, several health extension programs have been launched in the high-risk areas of the NCP. However, according to reports, the programs have not achieved the expected success due to non-compliance of the people of the target population. Under a context of uncertainty of proven facts, the effectiveness of such programs and compliance of people to risk reduction behaviour is brought into question by two interrelated socio-cognitive concerns. One concern raises the importance of knowing how the people living in epidemic areas perceive and interpret the disease in terms of causes and risk preventive methods. The second concern being the socio-cognitive determinants that may prevent people from adopting the expected risk reduction behaviour. Highlighting the importance of the above knowledge gap, this study attempts to understand how an agrarian population in Sri Lanka, vulnerable to CKDu, perceive the disease as a health risk. The study further explores, how their psycho-social beliefs structure preventive behaviour against the unknown disease under a context of uncertainty. To achieve the latter objective, the study refers to a theoretical framework based on an extended Protection Motivation Theory.

A common single nucleotide polymorphism (SNP) located in intron 4 of the EFEMP1 gene, rs3791675, has been reported to be associated with human height in European and Asian populations. The objective of this study is to examine the possible association of rs3791675-G with taller height in Oceanian populations. The rs3791675 SNP was genotyped for 636 adult subjects living in Tonga (Tonga population) and Solomon Islands (Munda, Kusaghe, and Rawaki populations). The allele frequency of rs3791675-G ranged from 0.29 to 0.66. A multiple regression analysis adjusted for age and sex was performed to test the association of rs3791675 with height in each population. The results revealed that a single copy of the rs3791675-G allele significantly increased height by 1.2 cm in Tonga population (P-value = 0.031), while no significant association was detected in Munda, Kusaghe, and Rawaki populations. Since the partial regression coefficients of rs3791675-G estimated in regression models were positive in all the populations, the lack of association in the Solomon Islanders may have come from small effect size of rs3791675-G in them as well as small sample size. To confirm the present finding, replication studies in other Oceanian populations are required.

This research was conducted in order to propose ways to reduce human exposure to DDT, especially for women of reproductive age in Bangladesh, and to find a relation between DDT exposure levels in serum and questionnaire information including sociodemographic and food frequency (FFQ). In this study, a significant relationship was found between the education level and BMI, and the serum p,p'-DDE concentration. This result suggests that people with higher education (relating to higher income) and BMI in Bangladesh actively buy expensive foodstuff, like meat and/or fatty fish, which relates to a higher fat intake. Additionally, a weak positive relationship between p,p'-DDE concentration in serum and the frequency of beef consumption was observed among the nullipara women subgroup. In a previous study, beef and fish showed large contributions on DDT intake of Bangladesh population. Those results suggest that the control of fatty food consumption such as meat (beef) and marine fish might help to regulate the levels of DDT.

The drastic depletion of elephant habitats in the dry zone of Sri Lanka has led to intense human-elephant conflict (HEC) in a region that is home to one of the celebrated agrarian settlements in Asia. Known as the tank villages, these settlements have a long history of human coexistence with elephants and other wild animals. However, the escalating incidence of human-elephant fatalities and crop losses to farmers indicates that the mode of interaction between the tank village inhabitants and the elephants has transformed from coexistence to conflict. Both population and agricultural land use pattern dynamics have contributed to agricultural expansion and loss of elephant habitat in the dry zone of Sri Lanka. However, our knowledge of how the agricultural land use pattern dynamics has contributed to the drastic depletion of elephant range in the dry zone is limited. This research attempted to gain insight into the role of agricultural land use dynamics on elephant habitat depletion and HEC in Sri Lanka through the study of Kuttikulama, a dry zone tank village. The data were collected through focus group discussions, key informant interviews and a cross sectional survey. The study revealed that agricultural land use patterns in traditional dry zone villages have changed in major ways over the last few decades. Such changes included the transition from a shifting-cultivation mode of farming to a fixed sequential mode of farming, the expansion of the per capita cropping area, and the disappearance of communality in agricultural land use patterns. The changes were found to have significantly contributed to a shift in human&ndash, elephant interactions from relatively harmonious ones to contentious ones. The study reveals the potential of traditional and alternative cropping and land use systems to minimize human-elephant conflict in Sri Lanka.

A missense variant (rs373863828:G A; p.Arg457Gln) of the CREBRF gene is strongly associated with a higher body mass index (BMI; kg/mThe aim of this study is to examine the association of rs373863828:G A with levels of serum lipids in four Pacific populations.A total of 613 adult subjects were recruited from Tonga (Polynesians) and the Solomon Islands (Melanesians and Micronesians). Multiple regression analyses adjusted for age and sex were performed to examine the association of rs373863828 with levels of serum lipids in each population.A significant association of rs373863828:G A with lower level of HDL-cholesterol was detected in the Tonga population (β = -3.32 and p-value = 0.030). The expected change in HDL-cholesterol with respect to a single copy of the rs373863828-A allele was 3.32 mg/dL. However, the association between rs373863828-A and lower levels of HDL-cholesterol was not significant after further adjustment for BMI in the Tonga population (β = -2.32 and p-value = 0.13).The rs373863828-A allele may not directly affect the level of serum HDL-cholesterol independent of BMI. To confirm the present findings, association studies with large sample sizes and functional analyses are required.

Objectives This study investigated morning salivary cortisol concentration in relation to total body fat composition among community-dwelling Papua New Guinean adults. Methods In addition to demographic and anthropometric measurements, saliva was collected in a single morning from 478 residents in Eastern Highlands Province and Madang Province. Results After adjusting for age, region, and occupation, the morning salivary cortisol concentration was significantly negatively correlated with body mass index among men (B = −0.01, P

In a recent cross-sectional investigation, we reported the intellectual function of adolescents (aged 14 and 15 years) in Bangladesh who had been exposed to arsenic (As). Here, we report a consecutive investigation on the intelligence quotient (IQ) of 408 children who are living in the Sonargoan Thana of Bangladesh (two age groups: 9 and 10 years; 4 and 5 years) were exposed to high levels of As in the groundwater. Urine and water samples were collected to assess As exposure. The IQ of the children was estimated using the Raven’s Standard Progressive Matrices and the Kaufman Brief Intelligence Test. Information on parents’ socioeconomic status (SES) was collected as confounding factors. The results indicate that As exposure was responsible for a lower IQ. The concentration of urinary As ([As]u) was associated with reduced intellectual function in a dose–response manner. A stronger association was found between reduced intellectual function (IQ) and [As]u than the level of As in the drinking water [As]w. There was no association between verbal IQ scores and [As]u of children in early childhood (aged 4 and 5 years). Based on these results, we conclude that current levels of As in the urine ([As]u), which we considered to reflect recent exposure to As from all possible sources, including groundwater, food, among others, were negatively associated to the IQ of the children tested, and that this adverse effect of As may also gradually accumulate over time among the poor.

The present study aims to investigate the relationship between arsenic (As) exposure and intelligence quotient (IQ) or social competence (SC) of Bangladeshi adolescents (aged 14 or 15 years) in Sonargaon thana. Information about socioeconomic status (SES) was collected as confounding factors. To evaluate the relative contribution of As sources to total As intake, the As concentrations in urine and drinking/cooking water, and the amount of water added in cooking, were assessed on site using a food frequency questionnaire (FFQ). The results confirmed that As exposure was essential to lower adolescent IQ or SC because they were negatively associated with As exposure after controlling for SES (particularly household income). Except for cooking water, the amount of drinking water varied with season and appeared to be the major As source because the As concentration in water was generally correlated with the As concentration in urine, and they were related to lower IQ or SC (even after controlling for SES). The FFQ survey revealed that rice was consumed the most frequently (more than once daily), followed by daal (bean) soup and nonleafy vegetables, but fish, meat, and eggs were consumed approximately once a week. Water intake per meal from cooked rice was estimated to be 616 mL/person, followed by bean soup (258 mL/person) and cooked vegetables (82 mL/person). Our results suggest that water used for cooking might be an important source of As, and the cooking process can affect the amount of As in cooked food.

The aim of this study was to assess the nutritional status and functional capacity of 144 community-dwelling elderly in three rural ethnic groups, namely, the Oy, the Brau and the Lao, of southern Laos.The Mini nutritional assessment (MNA) questionnaire and Determine Your Nutritional Health checklist were used to assess nutritional status. The Barthel Activities of Daily Living questionnaire and Lawton and Brody's Instrumental Activities of Daily Living questionnaire were used to assess the functional capacity of the respondents.The MNA score results indicated that 92.5 % of Oy respondents, 85.4 % of Brau respondents and 60 % of Lao respondents were malnourished. Analysis of variance tests showed that the MNA scores of the Oy and Lao ethnic groups and of the Brau and Lao ethnic groups were significantly different ( both p 0.01), but that there was no significant difference between the MNA scores of the Oy and Brau ethnic groups (p 0.05). In terms of functional capacity, 47.2 % of Oy respondents, 43.9 % of Brau respondents and 20 % of Lao respondents had limitations in their activities of daily living, whereas 98.1 % of Oy respondents, 97.6 % of Brau respondents and 86 % of Lao respondents had limitations in their instrumental activities of daily living. Body mass index, reduced appetite, number of meals consumed daily and presence of common diseases predicted nutritional status in all three ethnic groups; the remaining factors differed by ethnicity. This result implies that ethnic differences and other factors, such as location of the village, services, resources within the village and respondents' lifestyles, can affect nutritional status.Because predictors of nutritional status varied by ethnicity, there is a need for area-specific interventions aimed at improving the quality of life of the elderly in these areas.

It has been suggested that a ‘thrifty’ genotype hypothesis can account for high prevalence of obesity in the island populations of Oceania. A recent genome-wide association study revealed that a missense variant, rs373863828-A (p.Arg457Gln), of the CREBRF gene (encoding CREB3 regulatory factor) was associated with an excessive increase in body mass index (BMI) in Samoans. In the present study, the association of rs373863828-A with an increase in BMI was examined in four Austronesian (AN)-speaking populations in Oceania. We found that rs373863828-A was frequently observed (frequency of 0.15) in Tongans (Polynesians), and was strongly associated with higher BMI (P=6.1 × 10−4). A single copy of the rs373863828-A allele increased BMI by 3.09 kg m−2 after adjustment of age and sex. No significant association was detected in the other three AN-speaking populations (Melanesians and Micronesians) living in Solomon Islands. This was probably due to the low allele frequency (0.02–0.06) of rs373863828-A as well as small sample size. The rs373863828-A allele was not found in both AN-speaking and non-AN-speaking Melanesians living in Papua New Guinea. Our results suggest that rs373863828-A of CREBRF, a promising thrifty variant, arose in recent ancestors of AN-speaking Polynesians.

Human essential hypertension is partly caused by genetic factors. Angiotensinogen (AGT), G-protein β3-subunit (GNB3) and cytochrome P450 3A5 (CYP3A5) are candidate hypertension susceptibility genes and risk alleles at these loci have been thought to arise owing to human adaptation to climatic changes following the migration out-of-Africa. This study aimed to reveal the frequencies of hypertension-susceptibility genotypes in Pacific Island populations and associations of these single-nucleotide polymorphisms (SNPs) to hypertension. Genotyping was conducted for 804 individuals from Melanesian, Micronesian and Polynesian populations at SNPs in the genes encoding AGT (rs699, rs5049 and rs5051), GNB3 (rs5443) and CYP3A5*1/*3 (rs776746). Associations between these SNPs and hypertension were tested for 383 Melanesian Solomon Islanders. We found that the A/A genotype at rs5049 was a risk factor for hypertension (P=0.025) in the Melanesian Solomon Islanders; three SNPs for AGT were in linkage disequilibrium. The ancestral alleles of rs699, rs5051 and rs776746, and the derived allele of rs5443 were as frequent in the populations surveyed here as in other equatorial populations. Although other polymorphisms associated with hypertension and additional populations remain to be studied, these findings suggest that the Pacific Islanders' susceptibility to hypertension arose because of human migration and adaptation.

OBJECTIVE:Obesity is a growing health concern in the Oceanic populations. To investigate the genetic factors associated with adult obesity in the Oceanic populations, the association of single nucleotide polymorphisms (SNPs) of the beta-2 adrenergic receptor (ADRB2) gene with obesity was examined in 694 adults living in Tonga and Solomon Islands.\nRESULTS:A screening for variation in 16 Oceanic subjects detected 17 SNPs in the entire region of ADRB2, of which nine SNPs including two non-synonymous ones, rs1042713 (Arg16Gly) and rs1042714 (Gln27Glu), were further genotyped for all subjects. The rs34623097-A allele, at a SNP located upstream of ADRB2, showed the strongest association with risk for obesity in a logistic regression analysis adjusted for age, sex, and population (P=5.6 × 10^, odds ratio [OR]=2.5, 95% confidence interval [CI]=1.5–4.2). The 27Glu was also significantly associated with obesity in the single-point association analysis (P=0.013, OR=2.0, 95%CI=1.2–3.4); however, this association was no longer significant after adjustment for rs34623097 since these SNPs were in linkage disequilibrium with each other. A copy of the obesity-risk allele, rs34623097-A, led to a 1.6 kg/m^2 increase in body mass index (BMI; defined as weight in kilograms divided by height in meters squared) (P=0.0019). A luciferase reporter assay indicated that rs34623097-A reduced the transcriptional activity of the luciferase reporter gene by approximately 10% compared with rs34623097-G. An electrophoretic mobility shift assay demonstrated that rs34623097 modulated the binding affinity with nuclear factors. An evolutionary analysis implies that a G>A mutation at rs34623097 occurred in the Neandertal genome and then the rs34623097-A allele flowed into the ancestors of present-day humans.\nCONCLUSION:The present results suggest that rs34623097-A, which would lead to lower expression of ADRB2, contributes to the onset of obesity in the Oceanic populations., 論文

A community-based cross-sectional survey of 262 participants in four island communities of Manus, Papua New Guinea was conducted using a structured questionnaire to examine possible factors of malaria prevalence, including education experiences, knowledge, attitudes, and preventive behaviors, in relation to antimalarial antibody titers. Bivariate and multivariate analyses revealed that micro-environmental conditions caused inter-community differences in malaria prevalence. Ninety-nine percent of the subject villagers recognized mosquito bites as a cause of malaria transmission, which explains the high possession rate of bednets. There was a significant correlation between malaria education experience at schools and knowledge (p < 0.01) and between knowledge and bednet use (p < 0.05). However, regular bednet users were only 35% of the total, due primarily to feelings of discomfort, heat, and stuffiness inside the bednet. Villagers’ behavior of consulting an aid post orderly (APO) in case of high fever significantly lowered the titer level (p < 0.05), while their bednet use did not. This unexpected result was attributable to inappropriate bednet use and to daily living patterns, including both subsistence and social activities. We conclude that information regarding lifestyles and attitudes toward bednet use as well as malaria education experience at schools are particularly important for practical malaria prevention.

Various Pacific Island populations have experienced a marked increase in the prevalence of obesity in past decades. This study examined the association of a promoter polymorphism of the leptin gene (LEP), G-2548A (rs7799039), and two non-synonymous single nucleotide polymorphisms of the leptin receptor gene (LEPR), K109R (rs1137100) and Q223R (rs1137101), with body weight, body mass index (BMI) and obesity (BMIor = 30) in Pacific Islanders. A total of 745 Austronesian (AN)-speaking participants were analyzed after adjusting for age, gender, and population differences. The results revealed that carriers of the 223Q alleles of LEPR had significantly higher body weight (P = 0.0009) and BMI (P = 0.0022) than non-carriers (i.e., 223R homozygotes); furthermore, the 223Q carriers also had a signiWcantly higher risk of obesity in comparison to non-carriers (P = 0.0222). The other two polymorphisms, G-2548A and K109R, were associated with neither body weight, BMI, nor obesity. The 223Q allele was widely found among the AN-speaking study subjects, thus suggesting that the LEPR Q223R polymorphism is one of the factors contributing to the high prevalence of obesity in the Pacific Island populations.

It is suggested that the major prehistoric human colonizations of Oceania occurred twice, namely, about 50,000 and 4,000 years ago. The first settlers are considered as ancestors of indigenous people in New Guinea and Australia. The second settlers are Austronesian-speaking people who dispersed by voyaging in the Pacific Ocean. In this study, we performed genome-wide single-nucleotide polymorphism (SNP) typing on an indigenous Melanesian (Papuan) population, Gidra, and a Polynesian population, Tongans, by using the Affymetrix 500K assay. The SNP data were analyzed together with the data of the HapMap samples provided by Affymetrix. In agreement with previous studies, our phylogenetic analysis indicated that indigenous Melanesians are genetically closer to Asians than to Africans and European Americans. Population structure analyses revealed that the Tongan population is genetically originated from Asians at 70% and indigenous Melanesians at 30%, which thus supports the so-called Slow train model. We also applied the SNP data to genome-wide scans for positive selection by examining haplotypic variation and identified many candidates of locally selected genes. Providing a clue to understand human adaptation to environments, our approach based on evolutionary genetics must contribute to revealing unknown gene functions as well as functional differences between alleles. Conversely, this approach can also shed some light onto the invisible phenotypic differences between populations.

While many reports have outlined the health risk of chronic arsenic exposure on adult populations, relatively little is known about the effects on children. We have examined the effects of chronic arsenic exposure through consumption of contaminated groundwater among 241 children (age 4-15 yr) living in two rural villages in northern Bangladesh. The arsenic concentrations of the tubewell waters ranged from less than detection limit to 535 ng/mL, and in 72 of 241 (30%) tubewells, the water arsenic concentration exceeded 50 ng/mL, the provisional guideline of Bangladesh. Approximately half of the examined children exhibited dermatological symptoms with relatively obscured dose-response relationship; an observation suggesting that the children were no more susceptible to the dermatological effects of arsenic than the adults living in the same communities. Proportion of the children with lower BMI significantly increased with increasing arsenic exposure level; the dose-response relationship was consistently observed among the subgroups. These results suggested that while mild dermatological manifestations, potentially associated with arsenic exposure, could be found as much as half of the children, nutritional status of the children, evaluated by BMI, might be a sensitive endpoint than the dermatological manifestations among children in this area.

It has been suggested that Neel's "thrifty genotype" model may account for high body weights in some Oceanic populations, which presumably arose in modern times. In European populations, common variants (rs1421085-C, rs17817449-G, and rs9939609-A) in the fat mass and obesity (FTO associated) were recently found to be associated with body mass index (BMI) or obesity. In this study, we investigated the population frequencies of these variants in six Oceanic populations (Melanesians, Micronesians, and Polynesians) and tested for an association with BMI. Unlike European populations, the Oceanic populations displayed no significant association between the FTO polymorphisms and BMI. These variants were in strong linkage disequilibrium. The population frequencies ranged between 4.2 and 30.3% in the six Oceanic populations, and were similar to those in southeast and east Asian populations. Our study of the FTO polymorphisms has generated no evidence to support the thrifty genotype hypothesis for Oceanic populations.

This study investigated morning salivary cortisol concentration in relation to total body fat composition among community-dwelling Papua New Guinean adults.In addition to demographic and anthropometric measurements, saliva was collected in a single morning from 478 residents in Eastern Highlands Province and Madang Province.After adjusting for age, region, and occupation, the morning salivary cortisol concentration was significantly negatively correlated with body mass index among men (B = -0.01, P 0.05) and women (B = -0.013, P 0.05), and waist circumference (B = -0.007, P 0.05), waist-to-hip-ratio (B = -1.214, P 0.05), and subscapular-to-triceps skinfold-thickness ratio (B = -0.045, P 0.05) among men. Men with total or abdominal body fat mass known for elevated risk of non-communicable diseases displayed lower cortisol compared to men without such risk.Papua New Guinean adults with increased accumulation of body fat showed reduced cortisol concentration in morning saliva. Am. J. Hum. Biol. 28:587-590, 2016. © 2016 Wiley Periodicals, Inc.

Archaeological, linguistic, and genetic studies show that Austronesian (AN)-speaking Polynesian ancestors came from Asia/Taiwan to the Bismarck Archipelago in Near Oceania more than 3,600 years ago, and then expanded into Remote Oceania. However, it remains unclear whether they extensively mixed with indigenous Melanesians who had populated the Bismarck Archipelago before their arrival. To examine the extent of admixture between Polynesian ancestors and indigenous Melanesians, mitochondrial DNA (mtDNA) variations in the D-loop region and the cytochrome oxidase and lysine transfer RNA (COII/tRNA(Lys)) intergenic 9-bp deletion were analyzed in the following three Oceanian populations: 1) Balopa Islanders as AN-speaking Melanesians living in the northwestern end of the Bismarck Archipelago, 2) Tongans as AN-speaking Polynesians, and 3) Gidra as non-Austronesian-speaking Melanesians in the southwestern lowlands of Papua New Guinea. Phylogenetic analysis of mtDNA sequences revealed that more than 60% of mtDNA sequences in the Balopa Islanders were very similar to those in Tongans, suggesting an extensive gene flow from Polynesian ancestors to indigenous Melanesians. Furthermore, analysis of pairwise difference distributions for the D-loop sequences with the 9-bp deletion and the Polynesian motif (i.e., T16217C, A16247G, and C16261T) suggested that the expansion of Polynesian ancestors possessing these variations occurred approximately 7,000 years ago.

HLA-DRB1 polymorphism was investigated by molecular DNA-based typing in 37 Tongans living on Ha’ano island of the Ha’apai group. The predominant HLA-DRB1 alleles were DRB1*0901 (20.3%) and DRB1*0403 (18.9%). A principal component analysis of the DRB1 allele frequencies discriminated between the Polynesians and other Oceanian populations, including Melanesians, Micronesians, and Australian Aborigines. Both present and previous studies have shown that the allele frequency of DRB1*0901 is markedly high in Polynesians and Asians, while this allele is seldom found in Non-Austronesian (NAN)-speaking Melanesians, Micronesians, and Australian Aborigines. Furthermore, we analyzed the frequencies of allele coding for Arg at position 196 (196R: nucleotide [nt] 587G) of tumor necrosis factor receptor 2 (TNFR2, TNF-R75) in three Oceanian populations: Tongans, Austronesian (AN)-speaking Balopa islanders living in Manus province of Papua New Guinea, and NAN-speaking Gidra living in the southwestern lowlands of Papua New Guinea. The frequencies of the TNFR2-196R allele, observed at a relatively high frequency in East and Southeast Asian populations, were 24.0%, 7.3%, and 1.0% in the Tongans, Balopa islanders, and Gidra, respectively. Considering that the allele frequencies of DRB1*0901 and TNFR2 196R are relatively high in Asians, Polynesians, and AN-speaking Melanesians (Balopa islanders), but very low in NAN-speaking Melanesians (Gidra), we conclude that at least part of the AN-speaking Polynesian ancestors were derived from Asian populations, and that extensive gene flow from the Polynesian ancestors to the indigenous Melanesians occurred around their initial migration to Melanesia. This is consistent with the results from analyses of mitochondrial DNA and ABO blood group gene polymorphisms in the same study populations., 論文

Pacific Islands populations can be broadly divided into Austronesians (AN) and Non-Austronesians (NAN); obesity and type 2 diabetes are prevalent in the former, although leptin levels in both groups have seldom been investigated. Thirty-seven (20 male and 17 female) adult pairs, matched by age and percent body fat, from AN-speaking Balopa and NAN-speaking Huli, all of whom migrated to settle in Port Moresby, the capital of Papua New Guinea, were selected for comparison of their serum leptin concentrations. The Balopa did not differ significantly from the Huli in age (30.5 +/- 9.7 and 30.0 +/- 8.7 years for males, 33.7 +/- 8.9 and 34.1 +/- 7.5 years for females, respectively) or percent body fat (19.4 +/- 5.6 and 18.8 +/- 4.6 for males, 34.1 +/- 6.2 and 33.3 +/- 5.0 for females), although the BMI of females was lower in the Balopa (26.4 +/- 4.9) than in the Huli (29.7 +/- 4.7) (P = 0.02). In both ethnic groups, females had markedly higher leptin concentrations than males, but there was no significant inter-group difference in males (3.5 +/- 2.6 and 3.1 +/- 4.7 ng/ml, P = 0.14) or females (22.7 +/- 12.9 and 19.7 +/- 11.9 ng/ml, P = 0.40), after controlling for lifestyle factors and serum lipids. Multiple regression analysis revealed that significant predictors of leptin concentration were % body fat (beta = 0.58), sex (male, 0; female, 1; beta = 0.27), and smoker status (non-smoker, 0; smoker, 1; beta = -0.15) (R(2) = 0.80), implying that the leptin concentration was primarily determined by lifestyle-derived body fatness. In conclusion, the NAN populations do not endogenously differ in leptin status from the AN populations, who have been recognized as a typical group with a "thrifty" genotype.

Agricultural mechanization in Japan has progressed dramatically since 1955 with the introduction of tractors, harvesters, and processing machines. These technological developments have resulted in an increase in exposure to sources of noise that are not only annoying, but damaging to hearing. The present study was undertaken to determine, whether Japanese farmers are at risk for noise-induced hearing loss in comparison with office workers, and by evaluating the present conditions regarding occupational noise levels among agricultural workers. The results suggest that farmers, especially male farmers, have a high prevalence of hearing loss in the higher frequency ranges. Daily noise exposure levels in L Aeq ranged from 81.5 to 99.1 dBA for tea harvesting and processing, and from 83.2 to 97.6 for sugar cane harvesting. Taking into account their rather long working hours and excessive noise from farm machinery, it is concluded that farmers are at risk for noise-induced hearing loss. These findings clearly indicate a strong need for implementation of hearing conservation programs among agricultural workers exposed to machinery noise.

Exposure evaluation is an indispensable step for the risk assessment of chronic arsenic toxicity. The amount of water intake, which consists of the base of exposure calculation, has been lacking for the arsenic-affected populations in the developing countries. Thus, the purposes of the present study were (1) to estimate the water intake in such population, and (2) to estimate the relative importance of water versus food as the source of arsenic exposure. Adult males and females (n = 19 for each) were selected from two rural Bangladeshi communities that entirely depended on tubewells for their water supply. Their water intake was measured by two methods, a 24-h self-report and an interview with frequent visits. Results of the two methods generally agreed with each other in terms of correlation and the absolute intakes. Mean water intake obtained by the self-report method was found to be around 3 l/day with substantial individual variation (the maximum = 6 l/day), no sex difference, and a significant between-community difference. The calculation for total arsenic exposure demonstrated that there was no sex difference in arsenic exposure except when the exposure was mainly from food and thus relatively low. Although these results need to be further confirmed under various environmental settings, these results suggested that (1) the sex difference in the manifestation of arsenic toxicity previously observed in this area should be related with factors other than exposure level and that (2) the risks associated with low arsenic concentrations of groundwater should be carefully interpreted because food may be providing additional burden of arsenic.

A number of archeological, linguistic, and genetic studies have been carried out on the peopling of the Pacific, while the origin of Polynesians or the Lapita people is still open to debate. The Lapita people are believed to have populated the Bismarck Archipelago more than 3600 years ago. However, their Melanesian descendants still living in the Bismarck Archipelago have not been genetically clarified yet. To address this question, polymorphism of the ABO blood group gene was investigated in the following three populations who are considered to be almost free from recent admixtures: (i) Balopa islanders as Austronesian (AN)-speaking Melanesians living in the northwestern end of the Bismarck Archipelago; (ii) Gidra as non-Austronesian (NAN)-speaking Melanesians in southwestern lowlands of Papua New Guinea; and (iii) Tongan living in Ha'apai island as AN-speaking Polynesians. Interestingly, there were marked differences in allele frequencies of ABO*A101 and ABO*A102 among the three populations. The allele frequencies of ABO*A101 and ABO*A102 were 7.9 and 19.3% in Balopa, 23.2 and 0.0% in Gidra, and 2.9 and 25.0% in Tongan. Both phylogenetic and correspondence analyses suggested that Balopa was more close to Tongan than to Gidra and that Balopa was genetically placed between Tongan and Asian populations. Our results imply that Balopa may be Melanesian descendants of the Lapita people who populated the Bismarck Archipelago.

Health risks caused by the chronic exposure to arsenic-contaminated groundwater has been recognized in many Asian and Latin American countries. While the health effects among adults have been well documented, those among the younger generations including children, infants, babies, and fetus have been scarcely reported. In this minireview, possible effects of chronic arsenic exposure on the younger generations are discussed in terms of skin manifestations among the children, exposure among newborns and infants especially from the breast milk, child growth and development, reproductive performance. For each of the topics, our preliminary results obtained in an arsenic-contaminated area in Bangladesh will be described, followed by a brief overview on the recent publications dealing with the topic. Although there exist some human data that suggest possible effects on some of the above-mentioned endpoints, the data as a whole is too premature to conclude whether the arsenic poses serious threat to younger generations or not. Considering the public health importance of toxic effects imposed during the early life stages, it is clear that much more scientific efforts should be made to elucidate the possible effects of arsenic on the younger generations.

Perelik, Solang, and Mouk villages are located in Balopa islands of Papua New Guinea (PNG). It is known that languages spoken in Balopa belong to the same family of Austronesian languages, but the language of Mouk is different from others at a sub-family level. Most of Balopa islanders have subsisted mainly on horticulture and reef fishing, while Mouk villagers have depended on fishing and trading. In order to investigate the genetic similarities among Balopa islanders and their affinities to other Oceanian populations, HLA-DRB1 polymorphism was investigated in 98 individuals living in Perelik, Solang, and Mouk. The predominant HLA-DRB1 alleles in Balopa islands were HLA-DRB1*1502 and *1101. Interestingly, Mouk showed a similar distribution of DRB1 alleles to Solang despite their different language and subsistence. Genetic distance calculations and correspondence analysis based on DRB1 allele frequencies suggested that Balopa islanders genetically belong to Austronesians in Melanesia and are distant from other Austronesians in Micronesia or Polynesia.

Toxicological and metabolic interactions of selenium (Se) with arsenic (As) have been reported in many experimental studies. However, for human populations, possible interactions between As and Se and their toxicological significance have not been established. In this study, we have examined the relationship between Se and As in spot urine samples collected from the inhabitants of two rural communities of northeast Bangladesh. The urinary As (UAs) and Se (USe) concentrations were determined by hydride generation atomic absorption spectrometry (HGAAS). Negative correlation between UAs and USe was found in both males and females. Considering the exposure condition in these communities, it is unlikely that the correlation reflected the correlation between the intakes of these elements. This result suggests that As exposure from drinking water or food may change Se metabolism in humans. Possible toxicological significance of the interaction is discussed.

Background Arsenic contamination in groundwater affects 35 million people in Bangladesh, but the prevalence of arsenic contamination in local communities remains to be clarified. As skin manifestations are sensitive markers of arsenicosis, we examined the skin of adults and adolescents in two villages to elucidate the severity of arsenicosis. Methods Five hundred and sixty-one villagers were randomly selected for the evaluation of their skin. Three indicators, i.e. keratosis on the soles, keratosis on the palms, and melanosis and hypopigmentation on the trunk, were quantified for analysis. Results More than 50% of the villagers showed some skin manifestations due to arsenicosis. Keratosis on the soles was the most sensitive marker for the detection of arsenicosis at an early stage. Interestingly, the skin manifestations were more severe in males than in females. There was no correlation between the age and the severity of skin manifestations. Conclusions The prevalence of arsenicosis was quite high and males were more vulnerable to arsenic contamination. Using skin manifestations, especially keratosis on the soles, as useful markers to detect and evaluate arsenicosis, it is clear that there is an urgent need to assess the exact prevalence and severity of arsenicosis in the population of Bangladesh in order to take measures to treat and control this problem.

Fibreglass-reinforced plastics (FRP) factory workers are at high risk of developing occupational dermatoses because of their exposure to many chemicals used in the manufacture of plastics as well as to glass fibre or dust. Patch tests were carried out on 29 workers involved in FRP manufacturing processes where unsaturated polyester (UP) resin was used, to investigate the causes of their skin problems. Of the 22 workers who reported experiencing skin problems, 16 showed positive results to at least 1 chemical, including 6 cases of multiple sensitivity. 2 showed positive reactions to UP base resin, 6 to cobalt chloride, 5 to benzoyl peroxide (BPO), 4 to methyl ethyl ketone peroxide (MEKPO), 2 to para-tertiary butyl catechol (PTBC), 1 to styrene and 1 to formaldehyde. After taking into account their exposures and reported causes by questionnaires and their patch test results, 7 cases were diagnosed as allergic contact dermatitis (ACD) due to chemicals, 3 as irritant contact dermatitis (ICD) due to chemicals, and 3 as dermatitis due to mechanical irritation (MI) from glass fibre or dust, as well as 9 as ACD and/or MI. 18 of the total of 29 subjects (62.1%), including 2 workers without a history of skin problems, were sensitized to at least 1 chemical. Cobalt, peroxides, PTBC and UP base resin were the common causes of ACD.

Objective: Studies were carried out in Kumamoto, Japan to examine 1) the winter-summer differences in the average individual exposure to styrene (8hr-TWA) and to end-shift-urinary mandelic acid (MA in g/g Cr), 2) the possible seasonal difference in their relationship, and 3) the protective effect of a disposable particulate respirator containing charcoal fiber (called a “charcoal mask”) and a charcoal granule cartridge-mask (called a “gas mask”) in the real working conditions. Methods: Approximately 100 male and female workers from about 10 small industries were subjected to the studies first in winter and second in summer. Individual exposure to styrene was monitored with a passive sampler during work time, and end-shift-urine was collected to determine urinary MA excretion. The content of their activities and the types of protective equipment were observed and recorded by the minute throughout the working day. Results: Neither individual exposure to styrene nor urinary MA excretion differed at the time of the study in both “no-mask” and “gas mask” groups. The urinary MA excretion was related to individual exposure to styrene in both seasons, with the highest correlation coefficient in the “no-mask” group. Since the regression slope for the “charcoal mask” group did not differ from that for “no-mask” group, the “charcoal mask” was judged to have little protective effect in practical working conditions. From the difference in urinary MA values at 50 ppm (previous TLV-TWA by ACGIH) of individual exposure to styrene in the two regressions for “no-mask” and “gas mask” groups, 49% of styrene was protected against by the “gas mask” in winter, and 45% in summer. Conclusions: Despite different physical environmental conditions, individual exposure to styrene and urinary MA excretion did not differ by season in FRP-making industries. A “gas mask” is more recommended than a “charcoal mask” when treating styrene, although their protective effects are decreased in practical working settings. It is basically necessary to give correct information on and free access to such protective equipment to styrene-treating workers.

Two surveys, one in winter the other in summer time, examined the skin problems of the entire manual workers (N=148) from 11 small-to-medium sized fiber-glass reinforced plastics (FRP) factories located in Kyushu, Japan. The workers were exposed to unsaturated polyester resin, including styrene and auxiliary agents such as cobalt naphthenate, hardeners such as methyl ethyl ketone peroxides, glass fiber and dust including shortened glass fiber and plastic particles. Eighty- seven workers (58.8%) reported having skin problems (mainly itching or dermatitis) since they started to work in FRP manufacturing and 25 workers had consulted a physician because of their skin problems; one worker was forced to take sick leave because of his severe dermatitis. History of allergic diseases and shorter occupational period (duration of employment) in a FRP factory were associated with greater probability of having a history of work-related skin symptoms. Workers in factories where dust-generating and lamination sites were located in different buildings were significantly less likely to have a history of skin problems than those in factories where the two sites were located in the same building. Of the 67 workers examined in both seasons closed to double the prevalence of dermatitis was found in summer (23.3%) than winter (13.4%).

The toxicity of arsenic differs markedly between individuals and populations, which might be related to the metabolism (methylation) of inorganic arsenic (As), as well as the selenium (Se) nutritional status. Urinary excretion of As (u-As) and Se (u-Se) was examined in an adult population (n=128) living in an As-contaminated area in Bangladesh. Although there was a significant negative correlation between u-Se and u-As (median 137; range 49–927 μg/g creatinine), closer examination revealed a non-monotonous relationship between them. A quadratic curve with an axis of As at 155 μg/g Cre gave a better fit, and u-As and u-Se were positively or negatively correlated depending on whether the As concentration was lower or higher than 155 μg As/g Cre, respectively. Likewise, the relationships between the As methylation pattern and glutathione-S-transferase (GST) polymorphism, body mass index (BMI), and u-Se differed depending on the u-As range; i.e., higher or lower than 155 μg/g Cre. Although we did not determine the causal mechanism for these observations, the non-monotonic relationship between As exposure and the variables examined suggested the existence of a threshold at which the handling of As by human body is qualitatively changed. The possible importance of Se nutrition for As toxicity is also discussed.

Spot urine samples were collected from the inhabitants of two rural communities in northwestern Bangladesh. We compared arsenic levels in the urine samples ([As](u); n = 346) with those in water from tube wells ([As](tw); range < 1-535 microg/L; n = 86) on an individual basis. The small variation of [As](u) within subjects and highly positive correlation with [As](tw) indicate that [As](u) is a useful indicator of exposure. Analyses of [As](u) showed that creatinine correction was necessary, that [As](u) only reflected recent exposure, and that there were substantial interindividual differences for a given [As](tw) level. To evaluate the toxic effects of arsenic exposure, we constructed a system for rating skin manifestations, which revealed distinct sex-related differences. Comparison of males and females in the same households confirmed that skin manifestations were more severe in the males, and in the males of one community a dose-response relationship between [As](u) and the degree of skin manifestation was evident. The results of this study indicate that [As](u) in spot urine samples can be used as an exposure indicator for As. They suggest that there might be sex-related, and perhaps community-related, differences in the relationship between [As](u) and skin manifestations, although several confounding factors, including sunlight exposure and smoking habits, might contribute to the observed sex difference. The existence of such differences should be further confirmed and examined in other populations to identify the subpopulations sensitive to chronic arsenic toxicity.

For 197 adults and adolescents in four villages of three small islands in the Admiralty Islands, Papua New Guinea, antimalarial antibody titers were examined using the indirect fluorescent antibody test (IFAT) and malaria parasites were detected by the microtiter plate hybridisation (MPH) method using polymerase chain reaction (PCR) technique. The parasite rate (either Plasmodium falciparum or P. vivax, or both) averaged 39.2 %, varying from 31.1 % to 44.8 % among the four villages due to natural and artificial microenvironmental conditions related to breeding sites of mosquitoes ( Anopheles farauti). The lack of flat zones owing to geomorphological formation contributed to the lowest parasite rate in the extremely small island. However, human-modified environments such as a wet-land (naturally formed but artificially reformed) and an open well played significant roles in other inter-village differences. The present findings imply significant roles of microenvironment in diversified malaria prevalence and suggest some ways of mitigation of malarial hazards. Asia Pac J Public Health 2001; 13(2): 85-90

It is important to follow up on the health status of inhabitants living in the methyl mercury-polluted area surrounding Minamata City, paying particular attention to diseases not only of the central nervous system but also of other organs. We have been carrying out such concentric studies for more than 10 years. We have previously studied the cause-specific standard mortality ratios in Minamata disease patients and reported that the SMRs for liver disease and renal disease were significantly raised in male and female patients, respectively. It was also found that complications arising from diabetes could be due to the large number of old people among the autopsy cases. The next step was to clarify the actual prevalence and incidence of liver disease, renal disease, and diabetes mellitus epidemiologically among the population in this area. The aim of this study was to determine the actual prevalence of these diseases and complaints, and to investigate the contribution of various risk factors to these diseases in this area. The study was a population-based cross-sectional mass screening survey. A case-control study was designed to estimate the role of various risk factors including methyl mercury exposure for these diseases. A mass multiple health examination survey was performed in 1500 subjects aged 40 years and older in Tsunagi Town, neighboring Minamata City, every summer since 1984. Tsunagi Town is located in a methyl mercury-polluted area and there are 36.9 certified Minamata disease patients per 1000 population. Data concerning liver disease, renal disease, and diabetes mellitus were collected on the basis of urine, hematological, physical, and ultrasonographic examinations. Data on risk factors and subjective complaints were collected by interview and other measures. The prevalence of these diseases was not higher in this methyl mercury-polluted area compared with other areas in Japan, contrary to what was expected based on standard mortality ratios and pathological findings. There were no positive correlations between those diseases and methyl mercury exposure. On the other hand, the population in the polluted area had more and a greater variety of complaints than those in the nonpolluted area. It is possible that not only neurological subjective complaints but also nonspecific complaints of the population in the polluted area might be influenced by past methyl mercury exposure. This health surveillance in the population living in a methyl mercury-polluted area must be maintained in the future.

This study examined cardiovascular disease (CVD) risk factors, i.e., obesity, blood pressures, and serum lipoproteins and apoproteins, in relation to sociocultural characteristics in two rural-urban migrant populations (n = 173 adult males and females) in Port Moresby, the capital of Papua New Guinea. Tari migrants from the highlands and Balopa migrants from the islands differ genetically. More importantly, the lifestyle of the latter is more Westernized than that of the former in both Port Moresby and their homelands. The results demonstrate that CVD risk factors vary markedly among the origin/sex groups and that the length of stay in Port Moresby on CVD risk factors was significant only in Balopa males, most of whom had professional or skilled full-time jobs and were considered to have more stress. This study identified different CVD risk factors in the migrant groups: obesity or fatness for the Balopa migrants, and serum lipoproteins and apoproteins, particularly lipoprotein(a), for the Tari migrants. Am. J. Hum. Biol. 12:655-664, 2000. Copyright 2000 Wiley-Liss, Inc.

Recently farm mechanization has been widespread and developing rapidly, in particular riding farm machines are increasingly used in paddy fields in Japan. We have no information available on the actual situation regarding whole-body vibration on the seats of these farm machines from the standpoint of labour protection. Measurement and evaluation of whole-body vibration was performed on the seats of popular riding agricultural machineries. Whole-body vibration on the seats of combine harvesters and wheel tractors exceeded exposure limits and the fatigue-decreased proficiency boundary limit of 8 hr and also shortened the reduced comfort boundary limits of ISO 2631 (1985). Some combines, tractors and carieers had only less than one hour exposure duration as compared with the ISO 2631-1 standard (1997). On the other hand a questionnaire was also performed on the subject of agricultural machine operators. Any specific injury or other effects, i.e. low back injuries were not found among the group of operators as compared with those in non-operator farmers. It seems to be difficult to find out the health effects of whole-body vibration itself, because there may be a lot of causes, i.e. working posture, operating heavy materials, in farm working conditions.

Background:Our previous study demonstrated that the A-allele of the single nucleotide polymorphism (SNP) rs34623097 located in the upstream region of the β2 adrenergic receptor gene (ADRB2) is significantly associated with risk for obesity in Oceanic populations.\nMethods:To investigate whether the ADRB2 polymorphisms explain part of the individual differences in lipid mobilization, energy expenditure and glycogen breakdown, the associations of 10 ADRB2 SNPs with total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and triglyceride levels were examined in 128 adults in Tonga.\nResults:A multiple linear regression analysis adjusted for age, sex, and body mass index revealed that rs34623097 was significantly associated with triglyceride levels (P-value = 0.037). A copy of the rs34623097-A allele increased serum triglyceride levels by 70.1 mg/dL (0.791 mmol/L). None of the ADRB2 SNPs showed a significant association with total-cholesterol, high-density lipoprotein cholesterol, or low-density lipoprotein cholesterol.\nConclusions:In a Tongan population, a SNP located in the upstream region of ADRB2 is associated with triglyceride levels independent of body mass index., 論文

The carbon and nitrogen stable isotopic composition of the scalp hair and diet of Gidra-speaking people in four villages in Papua New Guinea is presented. The isotopic composition of hair was measured, while that of the diet was estimated from food consumption survey data and the measured isotopic composition and protein and carbohydrate contents of food items. The average isotopic ratios of the hair samples and of the diet varied among the four study villages, which were selected because of their diverse ecological settings. Comparison was made between hair and calculated dietary isotopic compositions. Two of the four diet-hair enrichment values obtained for 13C (+1.8 and 2.2%‰) were similar to those previously reported (1.4–2.0%‰), but the other two values (3.7 and 4.8%) were greater than in earlier reports. 15N enrichment was systematically greater (by 1%‰) than reported values (∼4.3%‰) except for one village, where a much greater enrichment (6.9%‰) was found. The factors potentially relevant to these deviations are discussed. Possible errors in estimating the dietary isotopic composition and minor modifications of dietary habits revealed by food consumption surveys could explain most of the discrepancies. However, the great enrichment of 15N found in one of the villages remains unexplained. © 1996 Wiley-Liss, Inc.

The relationship between changes in blood hemoglobin levels and physical growth at puberty is evaluated on the basis of the three to ten years follow up of the eight cohorts in 819 school girls. Yearly change of the average blod hemoglobin levels in eight cohorts of the different, age and number revealed that the levels in general increased slightly between 6 and 12 years old, and decreased between 13 and 14 years old. The additional study is attempted on 151 subjects with a mean age of 12 years who were closely followed up more than 3 years and had accurate physical growth and age of menarch as well as a characteristic change in blood hemoglobin levels. The subjects were divided into two groups; normal group (Gn) having hemoglobin above 12 g/dl throughout the observation period and anemic group (GL) detected less than 12 g/dl at least one time during the study. There was no significant difference in the growth of the two groups. With regard to the 161 subjects, there was a difference in their occurence, blood hemoglobin levels, ΔT [the duration between the peak of physical growth (Tp) and the age of menarch], (Tm) and so on, when compared the cohort whose ΔT is less than 0.5 year with the one whose ΔT is more than 2 years. Subjects with shorter ΔT had delayed Tp and early Tm, and their blood hemoglobin levels tended to decrease, whereas ones with longer ΔT had earlier Tp and delayed Tm, and the blood hemoglobin level tended to be high.

Adaptive diversity of Papua New Guinea peoples, represented by population densities varying from less than 1 person to more than 100 persons/km2, is mostly attributable to their agricultural systems in accordance with the natural and sociocultural environment. Comparison of long-term adaptation among several populations selected for highland/lowland status and degree of modernization is expected to clarify the causal relationships and to predict future potential. This article discusses relationships between productivity and sustainability of agriculture and population dynamics in the agrodiversified environment in Papua New Guinea.

In developed countries, deaths from infectious diseases have decreased and those from chronic diseases have increased with modernization. In many developing countries which are undergoing rapid modernization, these changes have been accelerated, with marked variation from population to population. A typical pattern is observed in the risks of chronic diseases, like cardiovascular disorders and diabetic mellitus, which are closely associated with activity pattern and food intake. This paper reviews the relationship between modernization and health conditions in South Pacific countries, Papua New Guinea in particular, and discusses the significance of health and diseases in achieving ongoing sustainable development.

Background: Arsenic acts as a carcinogen may be due to oxidative stress induction through the generation of reactive oxygen species (ROS). Gender disparity has been reported in many arsenic-exposur...