Browsing by Autor "Hillard Kaplan"

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Brain volume, energy balance, and cardiovascular health in two nonindustrial South American populations
(National Academy of Sciences, 2023) Hillard Kaplan; Paul L. Hooper; Margaret Gatz; Wendy J. Mack; Emma Law; Helena C. Chui; M. Linda Sutherland; James D. Sutherland; Christopher J. Rowan; L. Samüel Wann
Little is known about brain aging or dementia in nonindustrialized environments that are similar to how humans lived throughout evolutionary history. This paper examines brain volume (BV) in middle and old age among two indigenous South American populations, the Tsimane and Moseten, whose lifestyles and environments diverge from those in high-income nations. With a sample of 1,165 individuals aged 40 to 94, we analyze population differences in cross-sectional rates of decline in BV with age. We also assess the relationships of BV with energy biomarkers and arterial disease and compare them against findings in industrialized contexts. The analyses test three hypotheses derived from an evolutionary model of brain health, which we call the embarrassment of riches (EOR). The model hypothesizes that food energy was positively associated with late life BV in the physically active, food-limited past, but excess body mass and adiposity are now associated with reduced BV in industrialized societies in middle and older ages. We find that the relationship of BV with both non-HDL cholesterol and body mass index is curvilinear, positive from the lowest values to 1.4 to 1.6 SDs above the mean, and negative from that value to the highest values. The more acculturated Moseten exhibit a steeper decrease in BV with age than Tsimane, but still shallower than US and European populations. Lastly, aortic arteriosclerosis is associated with lower BV. Complemented by findings from the United States and Europe, our results are consistent with the EOR model, with implications for interventions to improve brain health.
Coronary atherosclerosis in indigenous South American Tsimane: a cross-sectional cohort study
(Elsevier BV, 2017) Hillard Kaplan; Randall C. Thompson; Benjamin C. Trumble; L. Samüel Wann; Adel H. Allam; Bret Beheim; Bruno Frøhlich; M. Linda Sutherland; James D. Sutherland; Jonathan Stieglitz
Does Blood Pressure Inevitably Rise With Age?
(Lippincott Williams & Wilkins, 2012) Michael Gurven; Aaron D. Blackwell; Daniel Eid Rodríguez; Jonathan Stieglitz; Hillard Kaplan
The rise in blood pressure with age is a major risk factor for cardiovascular and renal disease, stroke, and type 2 diabetes mellitus. Age-related increases in blood pressure have been observed in almost every population, except among hunter-gatherers, farmers, and pastoralists. Here we tested for age-related increases in blood pressure among Tsimane forager-farmers. We also test whether lifestyle changes associated with modernization lead to higher blood pressure and a greater rate of age-related increase in blood pressure. We measured blood pressure longitudinally on 2248 adults age ≥ 20 years (n=6468 observations over 8 years). Prevalence of hypertension was 3.9% for women and 5.2% for men, although diagnosis of persistent hypertension based on multiple observations reduced prevalence to 2.9% for both sexes. Mixed-effects models revealed systolic, diastolic, and pulse blood pressure increases of 2.86 (P<0.001), 0.95 (P<0.001), and 1.95 mmHg (P<0.001) per decade for women and 0.91 (P<0.001), 0.93 (P<0.001), and -0.02 mmHg (P=0.93) for men, substantially lower than rates found elsewhere. Lifestyle factors, such as smoking and Spanish fluency, had minimal effect on mean blood pressure and no effect on age-related increases in blood pressure. Greater town proximity was associated with a lower age-related increase in pulse pressure. Effects of modernization were, therefore, deemed minimal among Tsimane, in light of their lean physique, active lifestyle, and protective diet.
Female intrasexual competition and reputational effects on attractiveness among the Tsimane of Bolivia
(Elsevier BV, 2005) Stacey L. Rucas; Michael Gurven; Hillard Kaplan; Jeffrey Winking; Steven W. Gangestad; María Crespo
Health costs of reproduction are minimal despite high fertility, mortality and subsistence lifestyle
(Nature Portfolio, 2016) Michael Gurven; Megan Costa; Benjamin C. Trumble; Jonathan Stieglitz; Bret Beheim; Daniel Eid Rodríguez; Paul L. Hooper; Hillard Kaplan
Indirect genetic effects among neighbors promote cooperation and accelerate adaptation in a small-scale human society
(American Association for the Advancement of Science, 2025) Jordan S. Martin; Bret Beheim; Michael Gurven; Hillard Kaplan; Jonathan Stieglitz; Benjamin C. Trumble; Paul L. Hooper; Daniel K. Cummings; Daniel Eid Rodríguez; Adrian V. Jaeggi
Explaining the rapid evolution of human cooperation and its role in our species' biodemographic success remains a major evolutionary puzzle. To address this challenge, we tested a social drive hypothesis, which predicts that social plasticity and social selection in human groups cause indirect genetic effects that accelerate the adaptation of fitness, promoting population growth via feedback between the environmental causes and evolutionary consequences of cooperation. Using Bayesian multilevel models to analyze fertility data from a small-scale society, we demonstrate that density- and frequency-dependent indirect genetic effects on fitness promote the evolution of cooperation among neighboring women, increasing the rate of contemporary adaptation by ~5×. Our results show how interactions between the genetic and socioecological processes shaping cooperation in reproduction can drive rapid growth and social evolution in human populations.
Inflammation and Infection Do Not Promote Arterial Aging and Cardiovascular Disease Risk Factors among Lean Horticulturalists
(Public Library of Science, 2009) Michael Gurven; Hillard Kaplan; Jeffrey Winking; Daniel Eid Rodríguez; Sarinnapha M. Vasunilashorn; Jung Ki Kim; Caleb E. Finch; Eileen M. Crimmins
Inflammation may not always be a risk factor for arterial degeneration and CVD, but instead may be offset by other factors: healthy metabolism, active lifestyle, favorable body mass, lean diet, low blood lipids and cardiorespiratory health. Other possibilities, including genetic susceptibility and the role of helminth infections, are discussed. The absence of PAD and CVD among Tsimane parallels anecdotal reports from other small-scale subsistence populations and suggests that chronic vascular disease had little impact on adult mortality throughout most of human evolutionary history.
Mortality experience of Tsimane Amerindians of Bolivia: Regional variation and temporal trends
(Wiley, 2007) Michael Gurven; Hillard Kaplan; Alfredo Zelada Supa
This paper examines regional and temporal trends in mortality patterns among the Tsimane, a population of small-scale forager-horticulturalists in lowland Bolivia. We compare age-specific mortality in remote forest and riverine regions with that in more acculturated villages and examine mortality changes among all age groups over the past 50 years. Discrete-time logistic regression is used to examine impacts of region, period, sex, and age on mortality hazard. Villages in the remote forest and riverine regions show 2-4 times higher mortality rates from infancy until middle adulthood than in the acculturated region. While there was little change in mortality for most of the life course over the period 1950-1989, overall life expectancy at birth improved by 10 years from 45 to 53 after 1990. In both periods, over half of all deaths were due to infectious disease, especially respiratory and gastrointestinal infections. Accidents and violence accounted for a quarter of all deaths. Unlike typical patterns described by epidemiologic transition theory, we find a much larger period reduction of death rates during middle and late adulthood than during infancy or childhood. In the remote villages, infant death rates changed little, whereas death rates among older adults decreased sharply. We hypothesize that this pattern is due to a combination of differential access to medical interventions, a continued lack of public health infrastructure and Tsimane cultural beliefs concerning sickness and dying.
P2‐108: USING COMPUTED TOMOGRAPHY TO ASSESS BRAIN VOLUMETRICS IN AGING
(Wiley, 2019) Andrei Irimia; Hillard Kaplan; Ben C. Trumble; Juan J. Copajira Adrian; Alexander S. Maher; Kenneth A. Rostowsky; Nahian F. Chowdhury; M. Linda Sutherland; James D. Sutherland; Adel H. Allam
Although magnetic resonance imaging (MRI) remains the gold standard for the noninvasive evaluation of white matter (WM), gray matter (GM) and cerebrospinal fluid (CSF) volumes in the aging brain, CT continues to be used widely for brain imaging, particularly when MRI is unavailable or contraindicated. In developing countries, CT is often the only imaging modality available for evaluation of brain atrophy in patients with mild cognitive impairment (MCI) or Alzheimer's disease (AD). This has renewed interest in the development of approaches to use head CT to estimate brain volumetrics. A brain segmentation approach was developed to delineate WM, GM and CSF from head CT using probabilistic, atlas-based classification. Feasibility and utility were evaluated by comparing MRI-only to CT-only segmentations in 10 older adults [mean (μ) ± standard deviation (σ) of age = 65 ± 7 yrs; 5 females] from whom both MRI and CT scans were acquired within an eight-week period. Segmentation similarity was quantified using the Dice coefficient (DC), a robust measure of inter-modality tissue classification agreement. Comparison of MRI vs. CT segmentations yielded normally-distributed DCs [μ ± σ across participants: 85.5% ± 4.6% (WM), 86.7% ± 5.6% (GM) and 91.3% ± 2.8% (CSF)], indicating satisfactory ability to calculate brain volumetrics from the CT scans of the participants, relative to MRI measurements. For this sample, bootstrapping suggests that the tissue classification method is sufficiently sensitive to estimate WM, GM and CSF volumes within ∼5%, ∼4% and ∼3% of their MRI-based values, respectively. Compared to MRI, volumes computed from CT displayed no evidence of systematic over- or under-estimation [t (9) = 0.89, p > 0.80]. Our contribution broadens the ability to integrate CT imaging findings with other research on brain aging in health and disease, and complements other methodologies for the study of brain volumetrics in neurodegenerative diseases, including AD.
P3‐134: APOE GENOTYPE AND COGNITIVE PERFORMANCE IN TSIMANE AND MOSETEN OF BOLIVIA
(Wiley, 2019) Margaret Gatz; Hillard Kaplan; Ben C. Trumble; Randall C. Thompson; Juan J. Copajira Adrian; M. Linda Sutherland; James D. Sutherland; Helena C. Chui; Daniel Eid Rodriguez; Raúl Quispe Gutierrez
The ε4 allele of the apolipoprotein gene (APOE) is an established risk factor for Alzheimer's disease (AD), with evidence predominantly from Caucasian populations. Results are mixed whether non-demented older adult ε4 carriers perform more poorly on cognitive tests. Some evidence indicates that APOE influences AD risk through episodic memory. We therefore hypothesized ε4 carriers would show lower episodic memory scores. Participants were indigenous lowland Bolivians practicing subsistence level horticulture (469 Tsimane; 86 Moseten) aged ≥55 (mean 66, range 55-96), with data from both cognitive testing and APOE genotyping from PCR. Culturally/linguistically adapted cognitive tests included episodic memory, digit span forward, semantic fluency, visual scan, and visuoconstructional ability. Episodic memory included immediate memory (average of 3 learning trials for an 8-word list), and delayed recall assessed after 10 minutes. General linear modelling evaluated whether memory scores were associated with carrying the ε4 allele. Distribution of APOE genotypes was not significantly different between Tsimane and Moseten populations: unadjusted 21% ε3/ε4 heterozygotes; 1% ε4/ε4 homozygotes. Controlling for population, age, gender, and education, there was a significant effect for delayed recall: those carrying an ε4 allele scored significantly lower, b = −0.705, SE = 0.203, p = .0006, ηP2 = 0.024. Neither immediate memory nor any other cognitive test showed a significant ε4 effect. There were no significant interactions between APOE and population, age, gender, or education. Within each population, controlling for age, gender, and education, the ε4 main effect was significant on delayed recall for both Tsimane, b = −0.527, SE = 0.212, p = .0131, ηP2 = 0.0132, and Moseten, b = −0.935, SE = 0.427, p = .0316, ηP2 = 0.0558, with a trend for Moseten on immediate memory, b = −0.589, SE = 0.240, p = .0163, ηP2 = 0.0692.
Prehistoric Global Migration of Vanishing Gut Microbes With Humans
(2025) Matthew M. Carter; Zhiru Liu; Matthew R. Olm; Mélanie Martin; Daniel D. Sprockett; Benjamin C. Trumble; Hillard Kaplan; Jonathan Stieglitz; Daniel Eid Rodríguez; David A. Relman
Abstract The gut microbiome is crucial for health and greatly affected by lifestyle. Many microbes common in non-industrialized populations are disappearing or extinct in industrialized populations. Understanding which microbes have been long-term residents of the human gut, and may have co-evolved with humans, has implications for the importance of microbial biodiversity loss for health. However, the genetic complexities of microbial evolution and the plasticity of gut microbiome composition have made it challenging to define these long-term associations. Here, we performed deep metagenomic sequencing of the Tsimane horticulturalists of Bolivia and compared their gut microbiomes with the Hadza hunter-gatherers of Tanzania. These two populations, whose ancestors were separated for tens of thousands of years, share 1,231 microbial species, most of which are absent in industrialized populations. Population genetic analyses in 636 of these shared species revealed patterns of microbial divergence and gene flow consistent with prehistoric human co-migration, with estimated split times that approximately align with human migration out of Africa and into the Americas. Our findings indicate that a diverse gut microbiome co-migrated with humans around the globe, persisting over millennia. However, many of these species are now vanishing in industrialized populations, and the consequences for human health remain uncertain.
Subjective well-being across the life course among non-industrialized populations
(American Association for the Advancement of Science, 2024) Michael Gurven; Yoann Buoro; Daniel Eid Rodríguez; M. Katherine Sayre; Benjamin C. Trumble; Aili Pyhälä; Hillard Kaplan; Arild Angelsen; Jonathan Stieglitz; Victòria Reyes-García
Subjective well-being (SWB) is often described as being U-shaped over adulthood, declining to a midlife slump and then improving thereafter. Improved SWB in later adulthood has been considered a paradox given age-related declines in health and social losses. While SWB has mostly been studied in high-income countries, it remains largely unexplored in rural subsistence populations lacking formal institutions that reliably promote social welfare. Here, we evaluate the age profile of SWB among three small-scale subsistence societies (n = 468; study 1), forest users from 23 low-income countries (n = 6987; study 2), and Tsimane' horticulturalists (n = 1872; study 3). Across multiple specifications, we find variability in SWB age profiles. In some cases, we find no age-related differences in SWB or even inverted U-shapes. Adjusting for confounders reduces observed age effects. Our findings highlight variability in average well-being trajectories over the life course. Ensuring successful aging will require a greater focus on cultural and socioecological determinants of individual trajectories.
Voluntary collective isolation as a best response to COVID-19 for indigenous populations? A case study and protocol from the Bolivian Amazon
(Elsevier BV, 2020) Hillard Kaplan; Benjamin C. Trumble; Jonathan Stieglitz; Roberta Mendez Mamany; Maguin Gutierrez Cayuba; Leonardina Maito Moye; Sarah Alami; Thomas S. Kraft; Raúl Quispe Gutierrez; Juan Copajira Adrian