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Several reviews have assessed the relationship between exposure to ambient air pollution and adverse birth outcomes during pregnancy, but the results remain controversial. The objective of this study was to assess this correlation quantitatively and to explore sources of heterogeneity. We included all published case-control or cohort studies that evaluated the correlation between ambient air pollution and low birth weight (LBW), preterm birth (PTB), and small for gestational age (SGA). Analytical methods and inclusion criteria were provided on the PROSPERO website (CRD42018085816). We evaluated pooled effects and heterogeneity. Subgroup analyses (grouped by exposure period, study settings, study design, exposure types, data source, Newcastle-Ottawa quality score (NOS), and adjustment for smoking or meteorological factors) were also conducted and publication bias was examined. The risk of bias in systematic reviews (ROBIS) tool was used to evaluate the overall risk of bias in this review. Forty studies met the inclusion criteria. We observed pooled odds ratios (ORs) of 1.03-1.21 for LBW and 0.97-1.06 for PTB when mothers were exposed to CO, NO2, NOx, O3, PM2.5, PM10, or SO2 throughout their pregnancy. For SGA, the pooled estimate was 1.02 in relation to NO2 concentrations. Subgroup analysis and sensitivity analysis decreased the heterogeneity to some extent, such as the subgroups of continuous measures (OR=0.98 (0.97-0.99), I2=0.0%) and NOS>7 (OR=0.98 (0.97-0.99), I2=0.0%) in evaluating the association between PTB and NO2. This review was completed with a low risk of bias. High concentrations of air pollution were significantly related to the higher risk of adverse birth outcomes. However, the sources of heterogeneity among studies should be further explored. [ABSTRACT FROM AUTHOR]

Objective: This study investigated complementary feeding practices among four ethnic groups (Han, Uygur, Tibetan, and Zhuang) based on a cross-sectional survey in rural western China., Methods: In 2005, a stratified multistage cluster random sampling method was used to recruit 9712 children (7411 Han, 1032 Uygur, 678 Tibetan, and 591 Zhuang) between 6 and 35 months of age and their mothers from 45 counties in 10 provinces (autonomous regions, municipalities) in western China., Results: The rates of early introduction (before 6 months) of complementary foods in four ethnic groups (Han, Uygur, Tibetan, and Zhuang) were 71.30%, 95.95%, 82.40%, and 72.30%, respectively. The Infant and Child Feeding Index (ICFI) for Uygur and Tibetan children was lower than that for Han children at all age groups. Uygur children were more likely to have unqualified ICFI compared with Han children in a multivariate logistic regression (odds ratio (OR)=5.138, 95% confidence interval (CI): 4.340-6.084). A higher level of maternal education, greater family wealth, and the availability of complementary feeding educational materials decreased the likelihood of an unqualified ICFI. The nutritional status of children (Han, Tibetan, and Zhuang) with qualified ICFI was better than that for children with unqualified ICFI., Conclusions: Appropriate interventions are required to improve complementary feeding practices in rural western China.

Background: Preterm birth is a common cause of death in newborns and may result from many determinants, but evidence for the socioeconomic and environmental determinants of preterm birth in Tibetan women of childbearing age is limited. The aim of this study was to understand the current status of preterm birth in native Tibetan women and investigate the socioeconomic and environmental determinants., Methods: Data were drawn from a cohort study which was conducted from August 2006 to August 2012 in rural Lhasa, Tibet, China. A total of 1419 Tibetan pregnant women were followed from 20 weeks' gestation until delivery; the loss to follow-up rate was 4.69%. The incidence of preterm birth was estimated to show the status of preterm births in Tibet. Logistic regression models for longitudinal data were established, and odds ratios (ORs) together with 95% confidence intervals (CIs) were used to evaluate the association between the occurrence of preterm birth and 16 selected potential determinants based on the hierarchical conceptual frame., Results: The incidence of preterm birth was 4.58% (95% CI = 3.55-5.80%). After adjusting for health-related variables of the mothers and newborns, socioeconomic and environmental determinants associated with preterm birth included season (spring: OR = 0.28, 95% CI = 0.09-0.84; autumn: OR = 0.21, 95% CI = 0.06-0.69; and winter: OR = 0.31, 95% CI = 0.12-0.82) and calendar year of delivery (2010: OR = 5.03, 95% CI = 1.24-20.35; 2009: OR = 6.62, 95% CI = 1.75-25.10; and 2007-2008: OR = 5.93, 95% CI = 1.47-23.90)., Conclusions: The incidence of preterm birth among native Tibetan women was low and there was a decreasing trend in recent years; however, it is still essential to strengthen seasonal maternal care, extend the spacing between pregnancies, and reinforce adequate maternal nutrition.

Objective: To analyze the associations between menopause and hypertension/isolated systolic hypertension (ISH) among rural females in Hanzhong, Shaanxi Province, China., Methods: In this cross-sectional study, 3030 residents were selected by stratified random sampling and investigated by questionnaire survey and physical examinations. Data of the females were analyzed to explore the impact of menopause on blood pressure by quantile regression and to investigate the associations between menopause and hypertension, ISH, and isolated distolic hypertension (IDH) by logistic regression., Results: The number of premenopausal and postmenopausal women was 965 and 998. The average age was (41.0 ± 8.07) years in the premenopausal group and (58.0±7.12) years in the postmenopausal group (P<0.001). The prevalence of hypertension among the premenopausal group and postmenopausal group was 21.9% and 49.3%, respectively. Quantiles regression analysis showed that the impact of menopause on systolic blood pressure increased as the percentile increased. The diastolic blood pressure (DBP) of the premenopausal group was significantly lower than that in the postmenopausal at q ≥ 0.40(DBP = 84 mmHg,1 mmHg = 0.133 kPa) percentile points (P<0.05), while the difference was not significant at q≤ 0.30 (DBP=80 mmHg) percentile points(P>0.05). After the potential confounders including age, education level, marriage, occupational, hyperlipidemia, family history, exercise, sleep, watching TV, smoking, passive smoking, alcohol consumption, body mass index, wealth index, waist circumference were controlled, positive associations were observed between menopause and hypertension/ISH in logistic regression models., Conclusions: Menopause is positively related with hypertension/ISH. More effective interventions should be taken to prevent hypertension and ISH among rural women.

Objective: Using infant and child feeding index (ICFI) to evaluate the relationship between infant feeding and physical development indicators in rural areas of Lhasa., Methods: In July and August 2010 in the rural areas of Lhasa, the multi-stage cluster random sampling method was adopted to select 540 Tibetan children who were between 6 to 35 months of age. There were 70, 79 and 391 cases in 6 to 8, 9 to 11 and 12 to 35-month-old group respectively. The basic status of infants, information about breastfeeding and complementary feeding were collected by using designed questionnaires. Their height and weight were measured to calculate the children's weight for age Z-score (WAZ), height for age Z-score (HAZ) and weight for height Z-score (WHZ) and assess feeding index score (out of 17 scores) and analyze the relationship between feeding index and HAZ, WAZ and WHZ., Results: The mean ICFI score of 540 cases was 8.90 ± 2.82.It was 6.84 ± 3.16, 8.16 ± 2.78 and 9.41 ± 2.55 for 6 to 8, 9 to 11 and 12 to 35-month-old infants respectively. There was significant difference between the different month group (F = 30.99, P < 0.05).For the three month groups, the scores of WAZ were 0.10 ± 1.18, -0.09 ± 1.20 and -0.38 ± 0.96; HAZ were -0.60 ± 1.68, -1.02 ± 1.72 and -1.30 ± 1.30; WHZ were 0.62 ± 1.23, 0.69 ± 0.96 and 0.43 ± 0.95 respectively. The ICFI scores of 9 to 11, 12 to 35 and 6 to 35-month-old infants were positively correlated with HAZ (correlation coefficients were 0.25,0.12 and 0.09 respectively, all P values <0.05). There was no correlation with WAZ (correlation coefficients were 0.15,0.08 and 0.03 respectively, all P values >0.05) and WHZ (correlation coefficients were -0.08, -0.02, and -0.07 respectively, all P values >0.05). There were no correlation between ICFI score with HAZ, WAZ and WHZ for 6 to 8 month-old infants (correlation coefficient were 0.06,0.16 and -0.07 respectively, all P values >0.05)., Conclusion: To some extent, the feeding index can effectively reflect the growth status of these infants and can serve as a comprehensive assessment of feeding situations among Tibetan children in rural areas of Lhasa.

Objective: To analyze the fertility rate and to estimate the future population size of Shaanxi province, based on data from the sixth national population census., Methods: Fertility rate curve was used to analyze the fertility model and the abbreviated life table. The actual fertility rate was used as the main way to predict the future population size. General fertility rate was analyzed by factor analysis approach., Results: The total fertility rate of Shaanxi province was 1.05 in 2010 while age-specific fertility rate contributed 101.27% to the general fertility rate. The expected population sizes would be 38 122 474 in 2015, 38 432 931 in 2020 and 38 121 904 in 2025 respectively., Conclusion: Birthrate would become lower and the population size appearing a negative increase in the year 2020, in Shaanxi province.

Objective: To explore the ethnic differences on nutritional status of children under three years old, in the western areas of China and to identify the affecting factors., Methods: 14 072 children under the age of three years and their mothers were recruited, using the proportion population sampling method in 45 counties in the western areas of China. Height and weight were used as the measurement on nutrition of children., Results: Height and weight of children with Han, Uyghur, Tibetan and Zhuang ethnicities were all lower than the WHO standards and with differences on height and weight among them. There were also ethnic differences on the status of malnutrition. Prevalence rates of stunting were 14.7%, 20.3%, 26.9% and 26.5% for Han, Uyghur, Tibetan and Zhuang ethnicities, respectively. Prevalence rates of underweight were 6.1%, 10.7%, 6.8% and 15.5% among the Han, Uyghur, Tibetan and Zhuang ethnicities, respectively. The prevalence rates of wasting were 4.2%, 5.3%, 2.9%, 8.9%, and of under nutrition were 19.2%, 25.5%, 30.3% and 36.5% for the Han, the Uyghur, the Tibetan and the Zhuang ethnicities, respectively. When factors as family size, years of schooling of parents, family numbers, sex, age (months), mother's height and weight, ways of feeding and sources of family income etc. were adjusted, children with Uyghur, Tibetan, Zhuang and other ethnicities were still presented more malnutrition than the children with Han ethnicity., Conclusion: There were differences on malnutrition status of children under the age of three years among the studies on different ethnicities. Undernutrition was less than nutritional status, seen in children of the Han nationality than other minority ethnicities. Ethnicity seemed to be related to differences in the nutritional status of children in western China while children of the Han nationality would be better than other minorities on nutritional status if they were in same living conditional.

Objective: To evaluate the diet quality and the relative factors among rural residents in Hanzhong, Shaanxi province., Methods: A cross-sectional survey on dietary status together with a semi-quantitative food frequency questionnaire were conducted on rural residents aged from 18 to 80 in Hanzhong of Shaanxi in 2010. Diet quality was evaluated by using the Chinese Diet Balance Index (CDBI) scoring and evaluating system. Linear regression models were developed to identify factors that influencing the status of under/over intake., Results: 2748 rural residents were investigated with the average daily intake of grains, beans, heavily salted vegetables, plant oil, nuts and salt. Results showed that they were higher than average level of Chinese rural residents' (P < 0.01). 80% of the residents having their daily intake of grains, oil and salt exceeded, while animal food, diary food, egg, vegetable and fruits were lower (P < 0.01) than the RNIs. However, there was under intake noticed to some extent in some areas. The average values of DBI&#95;LBS and DBI&#95;HBS were 22.8 and 9.8. The proportions of moderate under intake (20 < DBI&#95;LBS ≤ 40) and moderate over intake (10 < DBI&#95;HBS ≤ 20) were 62.6% and 48.0%. The main factors that influenced the dietary under-intake were education level, fortune index, hypertension, physical activity, and time to watch television. The main factors that affected the over-intake of diet were sex, age, number of family numbers, intensity of labor, time to sleep, smoking and drinking habits., Conclusion: The main diet problem among the rural residents was under-dietary-intake, with over-intake to some extents, suggesting that it was necessary to strength the specific intervention program, to improve the diet quality in the residents of Hanzhong area.

Objective: To investigate the prevalences of overweight and obesity in the rural communities in Hanzhong, Shaanxi Province., Methods: A total of 3030 residents in the rural areas of Hanzhong city were selected by stratified random sampling method to take questionnaire-based survey and physical examinations., Results: The data of 3017 valid subjects (1048 men and 1969 women) entered the final analysis. The average body mass index was (22.9±4.2) kg/m(2) [(23.0±5.5) kg/m(2) in men and (22.9±3.2) kg/m(2) in women]. The prevalence rates of overweight and obesity were 27.9% and 5.9% respectively, and the standardized rates were 23.4% and 5.4%, respectively. More specifically, prevalence rates of overweight and obesity were 28.3% and 6.1% in men (standardized rates were 24.7% and 7.5%, respectively) and 27.6% and 5.8% (standardized rate were 22.8% and 4.5% respectively) in women. The overweight/obesity was more often in young and mid-aged married men with higher education and socioeconomic status and in middle-aged and older women with less education from wealthier households., Conclusion: The prevalences of overweight and obesity are relatively high in the rural areas of Hanzhong, and therefore effective interventions are warranted.

Objective: To understand the growth and malnutrition status of Tibetan children aged 0 to 35 months in rural Lhasa in 2010., Methods: Cross-sectional study and multistage sampling design were used to randomly select sampling units. A total of 640 children were studied. Height and weight were measured and nutritional status was evaluated with WHO reference in 2006 using Z-scores. Z-scores of weight-for-age (WAZ), Z-scores of height-for-age (HAZ) and Z-scores of weight-for-height (WHZ) were analyzed., Results: At the age of 18 - 35 months, the children in rural Lhasa were 3.0 cm shorter as compared to the China national length reference. At the age of 6 - 11, 12 - 17 months, weight ((8.84 ± 1.23) and (10.20 ± 1.08) kg) and length ((70.45 ± 4.46) and (76.73 ± 4.78) cm) of boys were significantly higher than girls (weight: (8.42 ± 1.30) and (9.59 ± 1.26) kg; length: (67.61 ± 3.98) and (74.25 ± 4.50) cm) (all P values < 0.05). WAZ and HAZ were -0.17 ± 1.11 and -1.11 ± 1.46, respectively. The HAZ of 18 - 23 months children (-1.51 ± 1.24) was significantly different from the HAZ of 0 - 5, 6 - 11, 12 - 17 months children (HAZ: -0.75 ± 1.50, -0.83 ± 1.72, -1.07 ± 1.55, respectively) (all P values < 0.05), comparison with the HAZ of 24 - 29, 30 - 35 months children (HAZ: -1.41 ± 1.25, -1.24 ± 1.05), the results showed that there were no significant difference (all P values > 0.05), HAZ of 18 - 23 months children was the lowest. The prevalence of stunting, underweight, and wasting were 24.6% (155/630), 5.4% (33/616) and 1.0% (6/608), respectively. The malnutrition of boys was more serious than that of girls, the stunting of 18 - 23 and 24 - 29 months children had reached 35.0% (36/103) and 29.1% (25/86), respectively., Conclusion: The growth and development status of children in rural Lhasa under 3 years old was poor, and the malnutrition of local children should not be ignored with variations by gender and months of age.

Objective: To examine the relationship between cigarette smoking and body mass index (BMI) as well as waist circumference (WC) of men from 9 rural districts of Hanzhong, Shaanxi province., Methods: Cross-sectional data was analyzed from Hanzhong Health Survey on rural residents in 2010. Quantile regression mode was used to compare the results using the BMI (WC) and smoking status (degree) as the dependent variables and independent variable and confounding factors were also controlled., Results: 1039 male residents of rural areas of Hanzhong city were investigated. The prevalence rates on overweight and obesity among the males were 28.0% and 5.9%, with central obesity as 35.0% and the rate of current cigarette smoking was 63.6% in the areas., Results: from the quantile regression showed that the relationship between smoking status and BMI beyond 80 percentile in men (BMI = 24.4) which was not significantly different BMI among the heavy smokers, was much higher than those mild smokers beyond 90 percentile (BMI = 24.9). WC of the current smokers was significantly higher than those ex-smokers beyond the 95 percentile (WC = 96.7 cm). WCs of the moderate and heavy smokers had an increase along with the increase of WCs beyond the 85 percentiles (WC = 89.9 cm)., Conclusion: The effect of smoking status and BMI (WC) were inconsistent, however, with BMI and WC increased among the subjects whose BMI or WC were at the high extreme end of the distribution. Thus, we should advise the obese subjects to quit smoking.

Objective: The objective of this study was to investigate the prevalence rate of abdominal obesity and to explore the associated risk factors in rural communities from Hanzhong area, Shaanxi province, and to provide baseline data for further targeted intervention programs., Methods: A cross-sectional study was conducted among all the participants with questionnaires, interview and physical examination. Nine townships were selected in Hanzhong area, followed by one village randomly chosen from the selected township, using the stratified random sampling method., Results: There were 3030 participants in this survey, among which 3021 samples were valid, including 1048 males and 1973 females. The overall prevalence rate of abdominal obesity was 38.9% (standardized rate as 33.4%) in rural communities of Hanzhong, and the prevalence rate on males abdominal obesity (35.0%) was significantly lower than that of females (40.9%). It was found that following factors as: being male, married, having more household wealth, frequent consumption of fried food, non-engagement of agricultural labor work, being nonsmoker or ex-smoker, spending longer time on watching-TV etc. were positively associated with the bigger odds of having abdominal obesity when using the logistic regression analysis. Meanwhile, data from this study indicated that factors as: at younger age, frequent participation in agricultural labor, under artificial feeding, with more years of education, less frequency of pregnancy etc. were negatively related to the prevalence of female abdominal obesity., Conclusion: The prevalence rate of abdominal obesity in Hanzhong area, Shaanxi province was significantly higher than the national average level which called for the development of related intervention programs to prevent chronic diseases associated with gender related-obesity in Hanzhong.

Objective: To investigate the relationship between dietary patterns and hypertension in Hanzhong city of Shanxi province., Methods: A cross-sectional survey on dietary pattern and hypertension together with a semi-quantitative food frequency questionnaire was conducted among rural residents aged from 18 to 80 in Hanzhong of Shanxi province in 2010. Factor analysis by SPSS was used to identify food patterns based on the frequency of food. Logistic regression was used to analyze the relationship between dietary patterns and hypertension., Results: 2929 rural residents were investigated with an average age as 50.0 years old and average schooling-years as 6.8. The prevalence rate of hypertension was 34.3%, with 35.4% in males and 33.7% in females. Among 29 kinds of food under investigation, only 11 kinds with the frequencies of consumption more than 1 time per week. Four main factors were derived as four dietary patterns by factor analysis and they were diversity dietary pattern, alcohol dietary pattern, beverage dietary pattern and simple dietary pattern. Among them, the balanced dietary pattern was significantly associated with hypertension. All the participants were categorized into 4 groups (Q1-Q4) according to their factor scores, quartile with Q1 as a reference. The residents who were more closer to having balance dietary pattern, were under less risk of suffering from hypertension after controlling for age, sex, BMI, education and income. Compared to Q1, the Q4 had lower risk of hypertension (OR = 0.59, 95%CI: 0.44 - 0.77) for the balanced pattern., Conclusion: Dietary pattern could be related to the prevalence of hypertension. A rational diet with diversity of foods should be suggested as one of the major measures for the prevention of hypertension.

Objective: To explore the dietary pattern of rural Tibetan women with children under 2 years of age., Methods: A cross-sectional survey on dietary pattern together with a semiquantitative food frequency questionnaire was conducted among Tibetan women in rural Lhasa in 2008., Results: 386 women were investigated with the average age as 28.5 years old and average schooling-years as 4.6. For each member in the woman's family, daily intake of vegetable oil was 25.9 g on average. Daily intake of butter, sugar and salt were 27.8 g, 12.9 g and 14.8 g respectively, which were higher than figures from national nutrition and health survey (P < 0.01). Among 91 kinds of food under investigation, only 22 kinds with the frequencies of consumption more than 1 time per day. Three main factors were derived by factor analysis. The first factor represented vegetable pattern characterized with vegetables, grains, fruits and a few animal foods. It was a dominant pattern for the subjects, which explained nearly 10% variance. The second one was Tibetan style pattern in which Tibetan foods and a few vegetables were consumed. The last one called meats and milk products pattern also reflected the Tibetan dietary style. Daily intake of energy for women was 2097.02 kcal which met 91.2% of Chinese recommended nutrients intake (RNI). Daily intake of protein and fat reached 82% of RNI and vitamin A but only 34.7% on RNI. Daily intake of calcium, iron and zinc reached 64.6%, 174.1% and 150.7% of RNI, receptively. Grains provided 65% of energy but only 7.4% of the energy and 15.5% of protein were from animal foods. "Tsampa" provided 57.6% of iron., Conclusion: Vegetable pattern had been the dominant dietary pattern among Tibetan women in rural Lhasa. Intake of energy, protein and some micronutrients were not sufficient.

Objective: To investigate the distribution of hemoglobin(Hb) and prevalence of anemia in pregnant women living in the Tibetan Plateau area., Methods: Random sampling method was used and fingertip blood sample was tested. Related sociodemographic information was collected. We adjusted the hemoglobin measurements based on the different levies of altitude, using three different methods from CDC, Dilren's and Dallman's to estimate the prevalence rates of anemia., Results: Three hundred and eighty pregnant women were included. The mean Hb was 127.6 g/L. Tibetan had a lower Hb (126.6 g/L) than people from other ethnicities (134.6 g/L) with rural pregnant women having a higher Hb (130.4 g/L) than that of urban ones (125.9 g/L). After controlling the gestational age, results remained the same. Different method used for correction of hemoglobin would cause different prevalence rates of anemia which were all higher than the pre-adjusted prevalence rates: 70.0% for CDC method, 77.9% for Dilren's method and 41.3% for Dallman's method respectively. After analyzing the erythrocyte parameters, we could not conclude that population in our study was under the early stage of the iron deficiency anemia., Conclusion: Higher altitude could affect the levels of hemoglobin concentration significantly. Currently adopted hemoglobin correction methods might not be suitable for Tibetan pregnant women. We suggested that it was imperative to establish a relationship between altitude and hemoglobin of Tibetan women during pregnancy in order to correctly evaluate the prevalence of anemia.

Objective: To investigate optimistic factors affecting nutrition status of infants under 3-year-old in rural areas of western China., Methods: The data used in this study came from a cross-sectional survey on primary health and maternal and child health care in western rural China. The method of stratified multistage cluster random sampling was used to obtain the sample of children. Composite index of anthropometric failure (CIAF) was used to classify the infants with normal nutrition or malnutrition. Logistic regression model was employed to investigate optimistic factors effecting nutrition of infants from 3 levels as family, mother and children themselves., Results: 14,532 qualified infants were obtained, 57.4% of them were boys. According to CIAF, 72.1% of children were found in normal nutritional status. Prevalence of malnutrition was 27.9% and 10.3% of children were both underweighted and retarded in growth. The result showed the children with better nutrition were from such families with high income, fathers with higher education and fewer children. Higher education for mothers and breastfeeding were optimistic factors effecting nutrition of infants under 6-month after family factors being controlled for. For children over 6 months old, the optimistic factors were heavy mother body weight and more education acquired, exclusive breast feeding within 4-month, introduction of foods containing more protein., Conclusion: Family factors strongly influence nutritional status of rural children. Improving mothers'education and adding protein intake for children older than 6 months make their nutrition status better.

Objective: To investigate sex difference on nutritional status, feeding practice and health care of rural children in western China., Methods: Data used in this study was from a large scale cross-sectional survey conducted in western rural areas of China. The total number of children younger than 3 years old was 14 532, in which 57.4% were boys. Logistic regression model was employed to control selected background factors for analysis of sex differential on nutritional status,feeding practice and health care of children., Results: The prevalence rates of stunting, underweight and wasting were close between both genders, regardless of north or south areas. After controlling of selected background factors, sex differentials in malnutrition happened only in north areas. It showed that boys having higher risk of being underweight than girls (OR = 1.27) in the families with one child and lower risk of being stunting than girls ( OR = 0.60). There was no sex differential found in stunting, underweight and wasting for any type of families in south areas. As for feeding practice egg was introduced to boys more frequently compared with girls,which was found in families with one child of south areas and ones with two children from the southern areas. More boys from families with two children of southern areas were exclusively breastfed within 4 months after birth. Data indicated boys had higher risk of being sick. Prevalence of anemia was 36.2% for boys,33.4% for girls. Prevalence of cold was 29.0% for boys,27.4% for girls. Prevalence of diarrhea was 19.0% for boys, 17.5% for girls. This sex differential persisted in the families of north areas after controlling for selected background factors., Conclusion: Sex differentials on nutritional status, feeding practice and health care exist in rural areas of western China, especially in north areas.

Objective: To study the status of spontaneous abortion among reproductive Tibetan women aged 15 - 49 years., Methods: A cross-sectional survey was conducted on reproductive history of Tibetan women and the sample was chosen under the stratified multistage cluster random sampling technique., Results: A total number of 3741 women were studied with a total number of 10,245 pregnancies. There were 386 spontaneous abortions reported with an incidence rate of 3.9%. Women living in the urban area had a higher rate than living in the rural areas. Women living in area where altitudes were above 4500 m, had a 2-time risk of having spontaneous abortion than those living in areas below 3500 m. The risk of having spontaneous abortion increased among women aged > or = 35 and those with more than 3 pregnancies., Conclusions: High altitude could contribute to the increase of spontaneous abortions incidence, suggesting that improvement of maternal care and nutrition and reduction of the frequency of pregnancy had important roles to play in reducing the incidence of spontaneous abortion among Tibetan women. Despite the fact that retrospective study on reproductive history could underestimate the incidence of spontaneous abortion, the incidence rate among Tibetan women might not be much higher than women living in the lowland areas.

Objective: To understand the current situation of maternal health care and the association between maternal health care and relevant factors., Methods: According to a cross sectional study design, 1512 mothers having children under 3 years old were drawn under stratified random sampling method and interviewed at their households in 15 counties, Tibet Autonomous Region of China., Results: 77.6% of the pregnant women received at least one antenatal checkup with an average of 3.89 times while the rate of antenatal checkup over 5 times was 26.3%. The hospital delivery rate was 40.4% in this area. 83.9% of the women received education under the health care program during pregnancy and 66.2% of them were visited by health workers after delivery. Major factors of the antenatal checkups would include the resource of income, living in nomadic area, personal sanitation, antenatal health care education, mobilization of delivery at hospital, knowledge of antenatal health care etc., Conclusions: There had been great improvement in women's health care in this area as compared with the status in 1999, but the frequency of receiving antenatal checkup was still not enough and the rate of hospital delivery was also low as compared with 46 counties in western areas of China. Poor knowledge of health care during pregnancy seemed to be the major factor that limited the utilization of antenatal health care. Knowledge on health and common sense of health care should be disseminated to improve the antenatal care and to enhance the hospital delivery rate.

Objective: To assess nutritional status among children younger than 3 years in 40 counties of western China, using anthropometry., Methods: With cross-sectional study and random sampling, a survey with a sample size of 7252 was conducted in 40 counties of western China on children under 3 years old. Height and weight were measured and nutrition status was evaluated with WHO/NCHS reference using Z scores., Results: SD of height for age (HA) and weight for age (WA) were 1.10 - 1.30 and 1.06 - 1.40, respectively and SD of WAZ for infants varied. The distribution of HA Z and WAZ shifted downward to 1 unit and 0.4 unit for distribution of weight for height (WHZ). The prevalence of stunting, underweight and wasting were 23.0%, 22.6% and 7.5% respectively. The prevalence rates were low among those yourger than 3 months. Stunting and underweight increased sharply after 6 months and reached 20% - 30%. Significant correlation was found between underweight and stunting or wasting with coefficients of 0.815 and 0.636, respectively. No correlation was found between stunting and wasting., Conclusion: The nutrition status adversely affected children as a whole but not only for individuals. There was a higher prevalence of malnutrition mainly on low height to children. Weight for age must be interpreted cautiously because of the inability of this indicator in distinguishing stunting and wasting just by itself. Assessment by anthropometry called for accurate information on age and measurement of height and weight.

Objective: To understand the prevalence of anemia in children living in poor rural villages in western China and to find out related factors affecting hemoglobin level of children so as to search for proper intervention., Methods: 3747 children under 3 years old and their families were studied using stratified random sampling in 40 counties in western China. Databases were set up, and data logically checked by Epi 6.0 software. All the data were input with duplication method and analyzed by SPSS 10.0 software., Results: The prevalence of anemia of children under 3-year-old was 32.7% in 40 counties with significant difference among provinces with the highest in Guizhou province (43.5%). The lowest was in Ningxia and Qinghai provinces, which was 20%. The prevalence of anemia of children was relatively high in 6 and 18 months of age after birth, but declining when children grew older. Many factors were associated with children's anemia, viz. feeding pattern, age, diarrhea, family income, nationality, mother with anemia and drinking clean water etc., Conclusion: Interventions as popularizing knowledge of appropriate feeding, drinking clean water and decreasing the prevalence of common diseases including diarrhea would decrease the prevalence of anemia of local children.

Objective: To study the hemoglobin status of children under the age of three years and the prevalence of anemia at high altitude., Methods: Cross-sectional study and randomly sampling were used. Blood was collected on tip of finger and the level of hemoglobin was measured using B-Hemoglobin photometer. We adjusted the hemoglobin based on altitude, using three methods of CDC, Direen's and Dallman's and then estimated the prevalence of anemia., Results: (1) 1 127 children were examined. The findings indicated that the average hemoglobin was about 120 g/L. There was no significant difference for Hb between boys and girls. Urban children had a higher hemoglobin level (123.3 g/L) than rural children (119.9 g/L). Analysis of covariance indicated that, after controlling the factor of altitude, the mean content of hemoglobin of rural children was lower than that of urban children and hemoglobin varied among districts. (2) Different method used for correction of hemoglobin caused different prevalence rates of anemia but they were higher than un-corrected prevalences: 90.4% for CDC method, 72.3% for Dirren's method and 65.0% for Dallman's method respectively., Conclusion: Higher altitude seemed to affect the levels of hemoglobin significantly. The prevalence of anemia in children might be higher, but current hemoglobin correction methods might not be suitable for correcting hemoglobin of Tibetan children. So we suggested that it was imperative to establish a relationship between altitude and hemoglobin of Tibetan children.

Objective: To understand the feeding status of Tibetan children aged below three years old., Methods: Cross-sectional study and randomly sampling were used. The information on complementary food was obtained through the recollection from mother of the child. Data of complementary food of Tibet children was compared with those of the children from the surveys of nine cities in China and 40 poor counties in western China., Results: One thousand six hundred and fifty-five children were studied. The findings indicated that the age of introduction of Zanba (a kind food of mixture of highland barley flour and butter) was 1.98 months after birth and the age of introduction of egg and meat was about 8 - 9 months. Boys were fed with Zanba earlier than girls but there was no significant difference in the introduction of other complementary food between sexes. Urban children were introduced with complementary food earlier than rural children, and children in the agricultural region earlier than those in the pasturing region. The proportion of no introduction of any complementary food by the age of 4 months was about 10.6% for urban children, but 21.7% for rural children while 14.2% for children in the agricultural region and 30.9% for children in the pasturing region. The proportion of no introduction of complementary food was 11.5% for Tibetan children compared with 45.2% for the children of 40 poor counties in western China. The proportions of introduction of the following complementary foods were 89.1% for Zanba, 22.1% for egg, 29.1% for fresh milk, 23.5% for meat, 17.5% for vegetable, 0.75% for bean products, 1.03% for fish and 3.35% for chicken respectively., Conclusions: The main complementary foods for Tibetan children included Zanba, milk, mutton and beef. There was a small amount of vegetable in diet. The introduction of bean, chicken and fish was not common. Early and monotony seemed to be the character of introduction of complementary food for Tibetan children. Improving introduction of complementary food is important in enhancing the nutritional status of Tibetan children.