Search

IntroductionWe evaluated the prevalence of dementia and mild cognitive impairment (MCI) in indigenous Tsimane and Moseten, who lead a subsistence lifestyle.MethodsParticipants from population-based samples ≥ 60 years of age (n = 623) were assessed using adapted versions of the Modified Mini-Mental State Examination, informant interview, longitudinal cognitive testing and brain computed tomography (CT) scans.ResultsTsimane exhibited five cases of dementia (among n = 435; crude prevalence = 1.2%, 95% confidence interval [CI]: 0.4, 2.7); Moseten exhibited one case (among n = 169; crude prevalence = 0.6%, 95% CI: 0.0, 3.2), all age ≥ 80 years. Age-standardized MCI prevalence was 7.7% (95% CI: 5.2, 10.3) in Tsimane and 9.8% (95% CI: 4.9, 14.6) in Moseten. Cognitive impairment was associated with visuospatial impairments, parkinsonian symptoms, and vascular calcification in the basal ganglia.DiscussionThe prevalence of dementia in this cohort is among the lowest in the world. Widespread intracranial medial arterial calcifications suggest a previously unrecognized, non-Alzheimer's disease (AD) dementia phenotype.

Brain atrophy is correlated with risk of cognitive impairment, functional decline, and dementia. Despite a high infectious disease burden, Tsimane forager-horticulturists of Bolivia have the lowest prevalence of coronary atherosclerosis of any studied population and present few cardiovascular disease (CVD) risk factors despite a high burden of infections and therefore inflammation. This study (a) examines the statistical association between brain volume (BV) and age for Tsimane and (b) compares this association to that of 3 industrialized populations in the United States and Europe. This cohort-based panel study enrolled 746 participants aged 40-94 (396 males), from whom computed tomography (CT) head scans were acquired. BV and intracranial volume (ICV) were calculated from automatic head CT segmentations. The linear regression coefficient estimate β^T of the Tsimane (T), describing the relationship between age (predictor) and BV (response, as a percentage of ICV), was calculated for the pooled sample (including both sexes) and for each sex. β^T was compared to the corresponding regression coefficient estimate β^R of samples from the industrialized reference (R) countries. For all comparisons, the null hypothesis β T = β R was rejected both for the combined samples of males and females, as well as separately for each sex. Our results indicate that the Tsimane exhibit a significantly slower decrease in BV with age than populations in the United States and Europe. Such reduced rates of BV decrease, together with a subsistence lifestyle and low CVD risk, may protect brain health despite considerable chronic inflammation related to infectious burden.

This article, published in the European Heart Journal, presents the findings of the HORUS study, which aimed to investigate the presence of atherosclerosis in ancient mummified humans. The study analyzed whole body CT scans of mummies from seven different cultures, including Egyptian, Peruvian, Bolivian, Unangan/Aleutian Islander, Greenlandic Inuit, ancestral Puebloan, and Middle-Ages Gobi Desert pastoralists. The results showed that atherosclerosis was present in all cultures except for one Indigenous Australian mummy. The study suggests that atherosclerosis has been a part of human populations for thousands of years and supports the existence of an innate human predisposition to the disease. [Extracted from the article]

BackgroundConventional coronary artery disease risk factors might potentially explain at least 90% of the attributable risk of coronary artery disease. To better understand the association between the pre-industrial lifestyle and low prevalence of coronary artery disease risk factors, we examined the Tsimane, a Bolivian population living a subsistence lifestyle of hunting, gathering, fishing, and farming with few cardiovascular risk factors, but high infectious inflammatory burden.MethodsWe did a cross-sectional cohort study including all individuals who self-identified as Tsimane and who were aged 40 years or older. Coronary atherosclerosis was assessed by coronary artery calcium (CAC) scoring done with non-contrast CT in Tsimane adults. We assessed the difference between the Tsimane and 6814 participants from the Multi-Ethnic Study of Atherosclerosis (MESA). CAC scores higher than 100 were considered representative of significant atherosclerotic disease. Tsimane blood lipid and inflammatory biomarkers were obtained at the time of scanning, and in some patients, longitudinally.FindingsBetween July 2, 2014, and Sept 10, 2015, 705 individuals, who had data available for analysis, were included in this study. 596 (85%) of 705 Tsimane had no CAC, 89 (13%) had CAC scores of 1-100, and 20 (3%) had CAC scores higher than 100. For individuals older than age 75 years, 31 (65%) Tsimane presented with a CAC score of 0, and only four (8%) had CAC scores of 100 or more, a five-fold lower prevalence than industrialised populations (p≤0·0001 for all age categories of MESA). Mean LDL and HDL cholesterol concentrations were 2·35 mmol/L (91 mg/dL) and 1·0 mmol/L (39·5 mg/dL), respectively; obesity, hypertension, high blood sugar, and regular cigarette smoking were rare. High-sensitivity C-reactive protein was elevated beyond the clinical cutoff of 3·0 mg/dL in 360 (51%) Tsimane participants.InterpretationDespite a high infectious inflammatory burden, the Tsimane, a forager-horticulturalist population of the Bolivian Amazon with few coronary artery disease risk factors, have the lowest reported levels of coronary artery disease of any population recorded to date. These findings suggest that coronary atherosclerosis can be avoided in most people by achieving a lifetime with very low LDL, low blood pressure, low glucose, normal body-mass index, no smoking, and plenty of physical activity. The relative contributions of each are still to be determined.FundingNational Institute on Aging, National Institutes of Health; St Luke's Hospital of Kansas City; and Paleocardiology Foundation.

This article discusses new insights into mummification techniques during Ancient Egypt's Middle Kingdom period. The study focuses on the non-destructive CT-scanning of the mummy of Lady Amanit, a priestess of Hathor. The research aims to reassess and reinterpret mummies using reliable scientific evidence, comparing visual examination with CT scanning. The study reveals the use of injection methods for organ removal and highlights the scarcity of mummies from the Old Kingdom compared to later periods. The research provides new insights into mummification techniques and contributes to the field of Egyptology. [Extracted from the article]

Background: Intracranial arteriosclerosis has been increasingly recognized as an etiological factor contributing to cognitive impairment. Indigenous Tsimane and Moseten, Amerindians of the Bolivian Amazon with physically‐active subsistence lifestyle, are reported to have lower prevalence of dementia (Gatz et al., Alzheimer's Dement, In press) and coronary artery disease (Kaplan et al.,Lancet,2017) than Western populations. We assessed the prevalence of intracranial arteriosclerosis, cerebrovascular calcifications, and leukoaraiosis in these populations and investigated their relationship with brain atrophy and cognition. Method: 155 participants aged ≥60 (60.6% females) underwent a non‐contrast computed tomography scan and cognitive testing. Visual rating scales were used to evaluate global cortical atrophy (GCA, simplified Pasquier), medial temporal atrophy (MTA, Scheltens), internal carotid artery (ICA) calcifications extent and morphology (Babiarz/Kockelkoren), lenticulostriate arteries (LSA) calcifications (de Brouwer), deep and periventricular leukoaraiosis (Fazekas). The maximum density (Hounsfield units) of LSA calcifications and the presence of infarcts and vertebral arteries (VA) calcifications were also evaluated. Result: Virtually all participants presented vascular calcifications in ICA (99.3%), LSA (87.4%), and VA (98.5%) (Fig.1,2). ICA calcification morphology was continuous in 58.7% and irregular/patchy in 40.5%, indicating medial and intimal pathology, respectively (Fig.3). In 13.2% of cases, the LSA calcifications were surrounded by parenchymal calcifications in the basal ganglia (Fig.4). Most cases showed no radiological sign of infarcts or leukoaraiosis. ICA calcifications correlated with age (P<.0001) while other calcification locations showed little association with age. LSA calcifications were greater in men than women (P<.01) with sex differences minimal for other calcification locations. After controlling for age and sex, ICA, LSA, basal ganglia and VA calcifications were related to greater GCA (all P<.05). LSA calcification density was significantly related to greater GCA and MTA, and to poorer visuo‐constructional ability (all P<.01). Prevalence of ICA and VA calcifications were higher compared to those reported in a population‐based European sample (79% and 16.9%, respectively; Vinke et al.,Neurobiol.Aging,2021). (Fig.5) Conclusion: Despite the low prevalence of dementia and coronary artery disease, cerebrovascular calcifications are commonly observed in this indigenous Bolivian population, and are associated with greater brain atrophy. Their underlying pathogenetic mechanisms remain unclear, but the high prevalence of infectious and inflammatory disorders might play a role. [ABSTRACT FROM AUTHOR]

Background In industrialized populations, low male testosterone is associated with higher rates of cardiovascular mortality. However, coronary risk factors like obesity impact both testosterone and cardiovascular outcomes. Here, we assess the role of endogenous testosterone on coronary artery calcium in an active subsistence population with relatively low testosterone levels, low cardiovascular risk and low coronary artery calcium scores. Methodology In this cross-sectional community-based study, 719 Tsimane forager-horticulturalists in the Bolivian Amazon aged 40+ years underwent computed tomography (49.8% male, mean age 57.6 years). Results Coronary artery calcium levels were low; 84.5% had no coronary artery calcium. Zero-inflated negative binomial models found testosterone was positively associated with coronary artery calcium for the full sample (Incidence Rate Ratio [IRR] = 1.477, 95% Confidence Interval [CI] 1.001–2.170, P = 0.031), and in a male-only subset (IRR = 1.532, 95% CI 0.993–2.360, P = 0.053). Testosterone was also positively associated with clinically relevant coronary atherosclerosis (calcium >100 Agatston units) in the full sample (Odds Ratio [OR] = 1.984, 95% CI 1.202–3.275, P = 0.007) and when limited to male-only sample (OR = 2.032, 95% CI 1.118–4.816, P = 0.024). Individuals with coronary artery calcium >100 had 20% higher levels of testosterone than those with calcium <100 (t = –3.201, P = 0.007). Conclusions and Implications Among Tsimane, testosterone is positively associated with coronary artery calcium despite generally low normal testosterone levels, minimal atherosclerosis and rare cardiovascular disease (CVD) events. Associations between low testosterone and CVD events in industrialized populations are likely confounded by obesity and other lifestyle factors. [ABSTRACT FROM AUTHOR]

The sternal foramen, usually an asymptomatic osteological defect, can lead to catastrophic consequences if not recognized prior to certain medical procedures. This study reports the prevalence of a sternal foramen in two South Amerindian populations compared with other published populations. We evaluated the presence of sternal foramina using thoracic computed tomography scans of 1334 (48% female) participants from two indigenous populations of Bolivia (n = 900 Tsimane, 434 Moseten). The prevalence of sternal foramina was compared to two U.S. populations of similar sex/age distribution (n = 572 Midwest Americans, 131 self-identified Native North Americans) via similar CT scans. A sternal foramen was significantly more common in the two Bolivian populations (prevalence ranging from 12.8 to 13.4%), compared to 4.4–5.1% in the two U.S. groups, consistent with prior estimates in studies from industrialized populations. Males had higher frequency of a sternal foramen compared to females in each of the four groups (OR = 1.904, 95% CI: 1.418–2.568, p < 0.001). Age was not associated with sternal foramen presence. These data show both a higher rate of sternal foramina in the South Amerindian populations versus comparator populations in North America and the highest rate of any studied living population. Although it is not possible to determine from our data the relative contribution of genetics versus early life or environmental causes to the higher rates of sternal foramen, we note that small prior studies have likewise demonstrated a higher prevalence in lower income countries. Further determination of the contributing factors warrants greater investigation and research. [ABSTRACT FROM AUTHOR]

We report on the scientific and historical study of a mummy associated with an Egyptian coffin once belonging to Count Aleksander Branicki, an important Polish collector who took part in two private expeditions to Egypt during the mid-nineteenth century. Recently the object was submitted for radiological investigation, as well as radiocarbon dating, in order to obtain a clearer picture of the biohistory and chronology of the body contained within the coffin. Furthermore, new documentary evidence was recovered that illustrates the colorful journey of the artifact and its contents from Egypt to Europe. [ABSTRACT FROM AUTHOR]