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1. Age-related physiological dysregulation progresses slowly in semi-free-ranging chimpanzees

   https://doi.org/10.1093/emph/eoae010  

   Cole, Megan_F ; Barnes, Paige ; Monroe, Isabelle_G ; Rukundo, Joshua ; Emery_Thompson, Melissa ; Rosati, Alexandra_G ( June 2024 , Evolution, Medicine, and Public Health)

   Lifestyle has widespread effects on human health and aging. Prior results from chimpanzees (Pan troglodytes), one of humans’ closest evolutionary relatives, indicate that these lifestyle effects may also be shared with other species, as semi-free-ranging chimpanzees fed a naturalistic diet show healthier values in several specific health biomarkers, compared with their sedentary, captive counterparts. Here, we examined how lifestyle factors associated with different environments affect rates of physiological aging in closely related chimpanzees.

   We compared physiological dysregulation, an index of biological aging, in semi-free-ranging chimpanzees in an African sanctuary versus captive chimpanzees in US laboratories. If the rate of aging is accelerated by high-calorie diet and sedentism, we predicted greater age-related dysregulation in the laboratory populations. Conversely, if costs of a wild lifestyle accelerate aging, then semi-free-ranging chimpanzees at the sanctuary, whose environment better approximates the wild, should show greater age-related dysregulation. We further tested whether dysregulation differed based on sex or body system, as in humans.

   We found that semi-free-ranging chimpanzees showed lower overall dysregulation, as well as lower age-related change in dysregulation, than laboratory chimpanzees. Males experienced lower dysregulation than females in both contexts, and the two populations exhibited distinct aging patterns based on body system.

   Our results support the conclusion that naturalistic living conditions result in healthier aging in chimpanzees. These data provide support for the proposal that lifestyle effects on human health and aging are conserved from deeper into our evolutionary history.

    

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2. Accelerated senescence as a cost of reproduction: Testing associations between oxidative stress and reproductive effort in rural and urban women

   https://doi.org/10.1002/ajhb.23537  

   Sancilio, Amelia ; Jasienska, Grazyna ; Panter‐Brick, Catherine ; Ziomkiewicz, Anna ; Nenko, Ilona ; Bribiescas, Richard G. ( November 2020 , American Journal of Human Biology)

   Oxidative stress is hypothesized to contribute to age‐related somatic deterioration. Both reproductive and ecological context may necessitate tradeoffs that influence this outcome. We examined whether measures of lifetime reproductive effort were related to levels of oxidative stress biomarkers in peri‐ and post‐menopausal women and whether associations were moderated by rural or urban residence.

   We surveyed 263 healthy women (age 62.1 ± 10.0 SD) from rural (N = 161) and urban Poland (N = 102), collecting sociodemographic data and urine samples to analyze biomarkers of oxidative stress (8‐oxo‐2′‐deoxyguanosine, 8‐OHdG) and antioxidative defense (copper‐zinc superoxide dismutase, Cu‐Zn SOD). Linear regression models, adjusted for residence, were used to test for associations between reproductive effort and 8‐OHdG and Cu‐Zn SOD.

   Univariate models demonstrated significant associations between gravidity and the biomarkers of oxidative stress (8‐OHdG:R² = 0.042,P ≤ .001; Cu‐Zn SOD:R² = 0.123,P ≤ .001). Multivariate models incorporating potential confounding variables, as well as cross‐product interaction terms, indicated that gravidity was associated with 8‐OHdG (P < .01,R²_adj = 0.067) and Cu‐Zn SOD (P = .01,R²_adj = 0.159). Residence (ie, urban vs rural) did not significantly moderate the associations between the biomarkers and reproductive effort.

   Higher lifetime reproductive effort contributes to increases in oxidative stress and antioxidative defenses. Our results provide evidence of potential mechanisms underlying the physiological tradeoffs influencing senescence for women with high reproductive effort. We illustrate the value of applying an evolutionary perspective to elucidate variation in human health and senescence.

    

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3. Immune cell type and DNA methylation vary with reproductive status in women: possible pathways for costs of reproduction

   https://doi.org/10.1093/emph/eoac003  

   Ryan, Calen P. ; Jones, Meaghan J. ; Edgar, Rachel D. ; Lee, Nanette R. ; Kobor, Michael S. ; McDade, Thomas W. ; Kuzawa, Christopher W. ( February 2022 , Evolution, Medicine, and Public Health)

   Consistent with evolutionarily theorized costs of reproduction (CoR), reproductive history in women is associated with life expectancy and susceptibility to certain cancers, autoimmune disorders and metabolic disease. Immunological changes originating during reproduction may help explain some of these relationships.

   To explore the potential role of the immune system in female CoR, we characterized leukocyte composition and regulatory processes using DNA methylation (DNAm) in a cross-sectional cohort of young (20–22 years old) women differing in reproductive status.

   Compared to nulliparity, pregnancy was characterized by differential methylation at 828 sites, 96% of which were hypomethylated and enriched for genes associated with T-cell activation, innate immunity, pre-eclampsia and neoplasia. Breastfeeding was associated with differential methylation at 1107 sites (71% hypermethylated), enriched for genes involved in metabolism, immune self-recognition and neurogenesis. There were no significant differences in DNAm between nulliparous and parous women. However, compared to nullipara, pregnant women had lower proportions of B, CD4T, CD8T and natural killer (NK) cells, and higher proportions of granulocytes and monocytes. Monocyte counts were lower and NK counts higher among breastfeeding women, and remained so among parous women.

   Our findings point to widespread differences in DNAm during pregnancy and lactation. These effects appear largely transient, but may accumulate with gravidity become detectable as women age. Nulliparous and parous women differed in leukocyte composition, consistent with more persistent effects of reproduction on cell type. These findings support transient (leukocyte DNAm) and persistent (cell composition) changes associated with reproduction in women, illuminating potential pathways contributing to CoR.

   Lay Summary: Evolutionary theory and epidemiology support costs of reproduction (CoR) to women’s health that may involve changes in immune function. We report differences in immune cell composition and gene regulation during pregnancy and breastfeeding. While many of these differences appear transient, immune cell composition may remain, suggesting mechanisms for female CoR.

    

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4. Varied Reproductive Histories of Ethnically Tibetan Women

   https://doi.org/10.33314/jnhrc.v19i04.3273  

   Sarna K, Cioffi G ( March 2022 , Journal of Nepal Health Research Council)

   Abstract Background: The U.N. health and well-being goals for 2030 focus on maternal and child health outcomes, among others. Challenges to meeting those goals vary widely throughout Nepal owing to the range of sociocultural factors, infrastructural limitations, physical geography and altitudes. This article explores sociocultural and biological influences on fertility and child survival among ethnically Tibetan women in Nepal. Methods: This is a cross sectional study of 430 women, age 46-86 years old, citizens of Nepal and native residents above 3500m in Mustang District, who provided interview and physiological data. Univariate Poisson regression analyses selected significant variables to include in multivariate Poisson regressions investigating the number of pregnancies, livebirths, child survival and death outcomes. Results: Earlier age at first pregnancy, later age at last pregnancy, and miscarriages associated with more pregnancies. Miscarriages and stillbirths associated with fewer livebirths. Higher maternal BMI and FEV6 associated with fewer children dying before age 15. Marital characteristics (status, type, continuity), contraceptive use, relative wealth, and education influenced these covariates. Conclusions: Low maternal pulmonary function and nutritional status predict poorer child survival in Upper Mustang. Addressing poor lung function and nutrition may improve reproductive outcomes among ethnically Tibetan women living at high altitude. Keywords: Child survival; fertility; high-altitude; Nepal; women.. 

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5. No impact of developmental conditions on serum estradiol levels among Bangladeshi women in the UK and Bangladesh

   https://doi.org/10.1002/ajhb.23631  

   Chaney, Carlye ; Begum, Khurshida ; Núñez‐de la Mora, Alejandra ; Sievert, Lynnette L. ; Muttukrishna, Shanthi ; Harries, Victoria ; Sharmeen, Taniya ; Murphy, Lorna ; Gunu, Richard ; Chowdhury, Osul ; et al ( June 2021 , American Journal of Human Biology)

   While many aspects of female ovarian function respond to environmental stressors, estradiol (E2) appears less sensitive to stressors than progesterone, except under extreme ecological conditions. However, earlier studies relied on saliva samples, considered less sensitive than blood. Here, we investigated E2 variation among 177 Bangladeshi and UK white women, aged 35–59, using single serum samples. Bangladeshi women either grew up in Sylhet, Bangladesh (exposed to poor sanitation, limited health care, and higher pathogen loads but not poor energy availability), or in the UK.

   We collected samples on days 4–6 of the menstrual cycle in menstruating women and on any day for post‐menopausal women. Participants included: (i) Bangladeshi sedentees (n = 36), (ii) Bangladeshis who migrated to the UK as adults (n = 52), (iii) Bangladeshis who migrated as children (n = 40), and (iv) UK white women matched for neighborhood residence to the migrants (n = 49). Serum was obtained by venipuncture and analyzed using electrochemiluminescence. We collected anthropometrics and supplementary sociodemographic and reproductive data through questionnaires. We analyzed the data using multivariate regression.

   E2 levels did not differ between migrant groups after controlling for age, BMI, physical activity, psychosocial stress, parity, and time since last birth (parous women). Paralleling results from salivary E2, serum E2 did not differ among women who experienced varying developmental conditions.

   Our results reinforce the hypothesis that E2 levels are stable under challenging environmental conditions. Interpopulation variation may only arise under chronic conditions of extreme nutritional scarcity, energy expenditure, and/or high disease burdens.

    

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