Browsing by Autor "Trumble, Benjamin C"

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Arterial Stiffness in Heart-Healthy Indigenous Tsimane Forager-Horticulturalists.
(2025) Cao, Tianyu; Linares, Edhitt C; Quispe Gutierrez, Raul; Eid Rodriguez, Daniel; Bani Cuata, Juana; Miyamoto, Michael I; von Rueden, Christopher R; Cummings, Daniel K; Hooper, Paul L; Trumble, Benjamin C; Stieglitz, Jonathan; Thompson, Randall C; Thomas, Gregory S; Kaplan, Hillard; Duprez, Daniel A; Jacobs, David R; Gurven, Michael
BACKGROUND: Little is known about arterial stiffness in rural subsistence populations that experience few cardiovascular risk factors. We conducted a cross-sectional study comparing 3 arterial stiffness metrics among Tsimane forager-horticulturalists with 2 representative US cohorts. METHODS: Arterial elasticity (the inverse of stiffness) markers C1 (large artery elasticity) and C2 (small artery elasticity) were measured using a tonometry device among 490 Tsimane adults (mean age, 51.2±10.1 years; 55% women), and compared with 6294 multiethnic US adults (mean age, 62.0±10.2 years; 52% women) from MESA (Multi-Ethnic Study of Atherosclerosis). Carotid-femoral pulse wave velocity was assessed using the foot-to-foot method in a smaller Tsimane sample (n=94) and compared with 3086 predominantly White US adults (mean age, 46.1±8.7 years; 54% women) from the FHS Gen3 (Framingham Heart Study Third Generation). RESULTS: Tsimane participants exhibited superior arterial health compared with US cohorts, with higher elasticity (C1/C2) and lower stiffness (carotid-femoral pulse wave velocity). Their C1 (mean 22.8±12.2 mL/mm Hg×10) and C2 (mean 7.5±4.0 mL/mm Hg×100) were 47.3% and 35.7% higher than MESA participants by age 40 years, respectively, and differences remained sustained throughout adulthood. Compared with participants in FHS Gen3, the carotid-femoral pulse wave velocity in Tsimane participants (mean 6.2±1.2 m/s) was 33.9% lower and showed a minimal age-related increase, with carotid-femoral pulse wave velocity only higher by age 70+ (β=1.74±0.38; reference <40 years). Tsimane participants with ≥2 comorbidities (hypertension, obesity, and diabetes) had ≈25% higher arterial elasticity than healthy Americans with no comorbidities. CONCLUSIONS: Tsimane forager-farmers of the Bolivian Amazon demonstrate substantially lower arterial stiffness throughout adulthood than more urbanized and sedentary populations, and the differences are only partially explained by conventional cardiometabolic risk factors.
Associations between male testosterone and immune function in a pathogenically stressed forager-horticultural population.
(2016) Trumble, Benjamin C; Blackwell, Aaron D; Stieglitz, Jonathan; Thompson, Melissa Emery; Suarez, Ivan Maldonado; Kaplan, Hillard; Gurven, Michael
OBJECTIVES: Despite well-known fitness advantages to males who produce and maintain high endogenous testosterone levels, such phenotypes may be costly if testosterone-mediated investment in reproductive effort trade-off against investment in somatic maintenance. Previous studies of androgen-mediated trade-offs in human immune function find mixed results, in part because most studies either focus on a few indicators of immunity, are confounded by phenotypic correlation, or are observational. Here the association between male endogenous testosterone and 13 circulating cytokines are examined before and after ex vivo antigen stimulation with phytohemagglutinin (PHA) and lipopolysaccharides (LPS) in a high pathogen population of Bolivian forager-horticulturalists. MATERIALS AND METHODS: A Milliplex 13-plex cytokine panel measured cytokine concentration in whole blood samples from 109 Tsimane men aged 40-89 (median = 50 years) before and after antigen stimulation with PHA and LPS. Urinary testosterone was measured via enzyme immunoassay, demographic, and anthropometric data were collected as part of the Tsimane Health and Life History Project. RESULTS: Higher endogenous testosterone was associated with down-regulated responses in all cytokines after PHA stimulation (but significantly in only 2/13 cytokines), controlling for age and body mass index. In contrast, testosterone was not significantly associated with down-regulation of cytokines after LPS stimulation. MANOVAs indicate that men with higher testosterone showed reduced cytokine responses to PHA compared with LPS (p = 0.0098). DISCUSSION: Endogenous testosterone appears to be immunomodulatory rather than immunosuppressive. Potentially costlier forms of immune activation like those induced by PHA (largely T-cell biased immune activation) are down-regulated in men with higher testosterone, but testosterone has less impact on potentially less costly immune activation following LPS stimulation (largely B-cell mediated immunity).
Challenging the Inevitability of Prostate Enlargement: Low Levels of Benign Prostatic Hyperplasia Among Tsimane Forager-Horticulturalists.
(2015) Trumble, Benjamin C; Stieglitz, Jonathan; Eid Rodriguez, Daniel; Cortez Linares, Edhitt; Kaplan, Hillard S; Gurven, Michael D
BACKGROUND: Often considered an inevitable part of male aging, benign prostatic hyperplasia (BPH) is the most common non-life threatening disease to affect men in Western populations. We examine age-related change in prostate size and BPH risk and related serum biomarkers among the Tsimane Amerindians of the Bolivian Amazon who live a traditional lifestyle of hunting and small-scale horticulture. The Tsimane are a critical case study for understanding the etiology of BPH as they have low levels of obesity and metabolic syndrome, as well as lower levels of testosterone than age matched U.S. males, factors associated with BPH in previous research. METHODS: Ultrasounds were conducted on 348 men aged 28-89 years (median age 56 years). Testosterone, prostate specific antigen, sex hormone binding globulin, and glycosylated hemoglobin were examined in relationship to prostate size and BPH. RESULTS: Tsimane have less than half of the BPH prevalence experienced by U.S. men, and prostate volumes 62.6% smaller. While Tsimane have low levels of testosterone and subclinical levels of metabolic syndrome compared to U.S. men, Tsimane with high testosterone were more likely to experience BPH, as were those with higher glycosylated hemoglobin, suggesting targets for clinical interventions to reduce BPH. CONCLUSIONS: These results have clinical significance for the growing number of men taking testosterone supplementation; even at low levels the additional testosterone exposure could be placing these men at higher risk of BPH. Overall, these data suggest that BPH may not have been an inevitable part of male aging throughout human evolutionary history.
Growth references for Tsimane forager-horticulturalists of the Bolivian Amazon.
(2017) Blackwell, Aaron D; Urlacher, Samuel S; Beheim, Bret; von Rueden, Christopher; Jaeggi, Adrian; Stieglitz, Jonathan; Trumble, Benjamin C; Gurven, Michael; Kaplan, Hillard
OBJECTIVES: Growth standards and references currently used to assess population and individual health are derived primarily from urban populations, including few individuals from indigenous or subsistence groups. Given environmental and genetic differences, growth may vary in these populations. Thus, there is a need to assess whether international standards are appropriate for all populations, and to produce population specific references if growth differs. Here we present and assess growth references for the Tsimane, an indigenous population of Bolivian forager-horticulturalists. METHODS: Mixed cross-sectional/longitudinal anthropometrics (9,614 individuals; 30,118 observations; ages 0-29 years) were used to generate centile curves and Lambda-Mu-Sigma (LMS) tables for height-for-age, weight-for-age, body mass index (BMI)-for-age, and weight-for-height (WFH) using Generalized Additive Models for Location Shape and Scale (GAMLSS). Velocity curves were generated using SuperImposition by Translation and Rotation (SITAR). Tsimane ≤5 years were compared to World Health Organization (WHO) standards while those >5 years were compared to WHO school age references. All ages were compared to published references for Shuar forager-horticulturalists of the Ecuadorian Amazon. RESULTS: Tsimane growth differs from WHO values in height and weight, but is similar for BMI and WFH. Tsimane growth is characterized by slow height velocity in childhood and early adolescent peak height velocity at 11.3 and 13.2 years for girls and boys. Tsimane growth patterns are similar to Shuar, suggesting shared features of growth among indigenous South Americans. CONCLUSIONS: International references for BMI-for-age and WFH are likely appropriate for Tsimane, but differences in height-for-age and weight-for-age suggest Tsimane specific references may be useful for these measures.
Helminth infection, fecundity, and age of first pregnancy in women.
(2015) Blackwell, Aaron D; Tamayo, Marilyne A; Beheim, Bret; Trumble, Benjamin C; Stieglitz, Jonathan; Hooper, Paul L; Martin, Melanie; Kaplan, Hillard; Gurven, Michael
Infection with intestinal helminths results in immunological changes that influence co-infections, and might influence fecundity by inducing immunological states affecting conception and pregnancy. We investigated associations between intestinal helminths and fertility in women, using 9 years of longitudinal data from 986 Bolivian forager-horticulturalists, experiencing natural fertility and 70% helminth prevalence. We found that different species of helminth are associated with contrasting effects on fecundity. Infection with roundworm (Ascaris lumbricoides) is associated with earlier first births and shortened interbirth intervals, whereas infection with hookworm is associated with delayed first pregnancy and extended interbirth intervals. Thus, helminths may have important effects on human fertility that reflect physiological and immunological consequences of infection.
Immune function in Amazonian horticulturalists.
(2016) Blackwell, Aaron D; Trumble, Benjamin C; Maldonado Suarez, Ivan; Stieglitz, Jonathan; Beheim, Bret; Snodgrass, J Josh; Kaplan, Hillard; Gurven, Michael
BACKGROUND: Amazonian populations are exposed to diverse parasites and pathogens, including protozoal, bacterial, fungal and helminthic infections. Yet much knowledge of the immune system is based on industrialised populations where these infections are relatively rare. AIM: This study examines distributions and age-related differences in 22 measures of immune function for Bolivian forager-horticulturalists and US and European populations. SUBJECTS AND METHODS: Subjects were 6338 Tsimane aged 0-90 years. Blood samples collected between 2004-2014 were analysed for 5-part blood differentials, C-reactive protein, erythrocyte sedimentation rate (ESR) and total immunoglobulins E, G, A and M. Flow cytometry was used to quantify naïve and non-naïve CD4 and CD8 T cells, natural killer cells, and B cells. RESULTS: Compared to reference populations, Tsimane have elevated levels of most immunological parameters, particularly immunoglobulins, eosinophils, ESR, B cells, and natural killer cells. However, monocytes and basophils are reduced and naïve CD4 cells depleted in older age groups. CONCLUSION: Tsimane ecology leads to lymphocyte repertoires and immunoglobulin profiles that differ from those observed in industrialised populations. These differences have consequences for disease susceptibility and co-vary with patterns of other life history traits, such as growth and reproduction.
Voluntary collective isolation as a best response to COVID-19 for indigenous populations? A case study and protocol from the Bolivian Amazon.
(2020) Kaplan, Hillard S; Trumble, Benjamin C; Stieglitz, Jonathan; Mamany, Roberta Mendez; Cayuba, Maguin Gutierrez; Moye, Leonardina Maito; Alami, Sarah; Kraft, Thomas; Gutierrez, Raul Quispe; Adrian, Juan Copajira; Thompson, Randall C; Thomas, Gregory S; Michalik, David E; Rodriguez, Daniel Eid; Gurven, Michael D
Indigenous communities worldwide share common features that make them especially vulnerable to the complications of and mortality from COVID-19. They also possess resilient attributes that can be leveraged to promote prevention efforts. How can indigenous communities best mitigate potential devastating effects of COVID-19? In Bolivia, where nearly half of all citizens claim indigenous origins, no specific guidelines have been outlined for indigenous communities inhabiting native communal territories. In this Public Health article, we describe collaborative efforts, as anthropologists, physicians, tribal leaders, and local officials, to develop and implement a multiphase COVID-19 prevention and containment plan focused on voluntary collective isolation and contact-tracing among Tsimane forager-horticulturalists in the Bolivian Amazon. Phase 1 involves education, outreach, and preparation, and phase 2 focuses on containment, patient management, and quarantine. Features of this plan might be exported and adapted to local circumstances elsewhere to prevent widespread mortality in indigenous communities.