Browsing by Autor "Stephanie V. Koebele"

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Apolipoprotein- ε 4 is associated with higher fecundity in a natural fertility population
(American Association for the Advancement of Science, 2023) Benjamin C. Trumble; Mia Charifson; Thomas S. Kraft; Angela R. García; Daniel K. Cummings; Paul L. Hooper; Amanda J. Lea; Daniel Eid Rodríguez; Stephanie V. Koebele; Kenneth H. Buetow
In many populations, the apolipoprotein-ε4 (APOE-ε4) allele increases the risk for several chronic diseases of aging, including dementia and cardiovascular disease; despite these harmful effects at later ages, the APOE-ε4 allele remains prevalent. We assess the impact of APOE-ε4 on fertility and its proximate determinants (age at first reproduction, interbirth interval) among the Tsimane, a natural fertility population of forager-horticulturalists. Among 795 women aged 13 to 90 (20% APOE-ε4 carriers), those with at least one APOE-ε4 allele had 0.3 to 0.5 more children than (ε3/ε3) homozygotes, while those with two APOE-ε4 alleles gave birth to 1.4 to 2.1 more children. APOE-ε4 carriers achieve higher fertility by beginning reproduction 0.8 years earlier and having a 0.23-year shorter interbirth interval. Our findings add to a growing body of literature suggesting a need for studies of populations living in ancestrally relevant environments to assess how alleles that are deleterious in sedentary urban environments may have been maintained by selection throughout human evolutionary history.
Inflammaging is minimal among forager-horticulturalists in the Bolivian Amazon
(Royal Society, 2025) Jacob E. Aronoff; Carrie L. Jenkins; Angela R. García; Stephanie V. Koebele; Suhail Ghafoor; Kate L. Woolard; Mia Charifson; Ivan Maldonado Suarez; Daniel Eid Rodríguez; Bret Beheim
An increase in chronic systemic inflammation in later life, termed inflammaging, is implicated in health risk. However, it is unclear whether inflammaging develops in all human populations, or if it is the product of environmental mismatch. We assessed inflammaging in Tsimane forager-horticulturalists of the Bolivian Amazon, using serum cytokines in a primarily cross-sectional sample (1134 samples from n = 714 individuals, age 39-94, 51.3% female). IL-6 was positively associated with age (β = 0.013, p < 0.01). However, other pro-inflammatory markers, including IL-1β and TNF-α, did not increase with age (β = -0.005 and β = -0.001, respectively). We then compared the Moseten, a neighbouring population that has experienced greater market integration (423 samples from n = 380 individuals, age 39-85, 48.2% female). The Moseten also showed a positive age association for IL-6 that attenuated at later ages (age β = 0.025, p < 0.01; age2 β = -0.001, p < 0.05). Further, IL-1β and TNF-α were both positively associated with age (β = 0.021, p < 0.05 and β = 0.011, p < 0.01, respectively). Our results demonstrate minimal inflammaging in the Tsimane, highlighting variation across populations in this age-related process. They also suggest that inflammaging is exacerbated by lifestyle shifts.
Testosterone is positively associated with coronary artery calcium in a low cardiovascular disease risk population
(University of Oxford, 2023) Benjamin C. Trumble; Jacob D. Negrey; Stephanie V. Koebele; Randall C. Thompson; L. Samüel Wann; Adel H. Allam; Bret Beheim; M. Linda Sutherland; James D. Sutherland; Daniel Eid Rodríguez
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.