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Introduction: Menarcheal timing is associated with growth, development, health, wellbeing, and reproduction across the lifespan. Although sexual orientation is a known correlate of health and developmental inequities, relatively little evolutionarily framed research has investigated sexual orientation-based variation in maturational timing. To improve our understanding of menarcheal timing among sexual minority (SM) people, we use a biocultural-evolutionary life history lens that takes into account the stresses of minoritization to examine the relationship between sexual orientation and self-reported age at menarche in a sample of American adults. Methods: Using the U.S. National Health and Nutrition Examination Survey (NHANES), a large, nationally representative dataset (n = 9757), we fit multiple logistic regression models and survival curves to evaluate associations between sexual orientation, indicators of somatic and material resources during adolescence (e.g., education, citizenship, upper arm length), and self-reported menarche. Results: SM respondents were more likely to report earlier (by 4–5 months) ages of menarche (p

Eliminating health inequities through reconfiguring major social determinants of health, including discriminatory exclusion from access to power and material resources during early life stages like pregnancy, are among Canada’s policy and health provision priorities. To date, though, the role of racism in determining pregnancy or downstream health in Canada has been under-explored. We investigated whether each of seven pregnancy health/health experiences indicators was associated with a proxy for racialization (implicitly, racism) and/or newcomer-to-Canada status, using logistic regression models fit to questionnaire responses from 300 pregnant people from Hamilton, Ontario. Quantitative analyses were contextualized with thematic data from focus group discussions (FGDs) with 63 pregnant/new parent and/or care provider (e.g., midwives) participants. Racialization, sometimes compounded by intersecting newcomer-to-Canada status, was associated with two-fold+ increased odds of reporting four pregnancy health/health experiences indicators: complications, inadequate weight gain, low general self-efficacy, and perceived decline in overall health during pregnancy. Yet, while poverty and immigration emerged from FGDs as themes salient to pregnancy health, racism did not. Racialization predicts adverse pregnancy health/health experiences in this sample, despite Hamiltonian’s tendency to discount racism as determining pregnancy health. More aggressively anti-racist, intersectional, poverty-reducing policies are needed in Canada to ameliorate pregnancy inequities and promote health equity.

This systematic review project aims to bring together current quantitative, qualitative, and mixed-methods-based evidence regarding any health-related correlates of food insecurity and/or housing insecurity during the peri-conceptional, prenatal, and peri-natal periods for pregnant/ birthing women and people living in wealthy, Western democracies.

Background: The impact of the coronavirus disease 2019 (COVID-19) pandemic and the public health measures put in place to control COVID-19 transmissions (e.g., social distancing, self-isolation) is heterogenous, with greater consequences among populations experiencing social, economic, and political marginalization, including members of the 2-Spirit, Lesbian, Gay, Bisexual, Trans, Queer, (2SLGBTQ+) community. Methods: Using a biocultural approach, we examine the mental health impacts of the COVID-19 pandemic using data from a mixed methods study of 455 self-identified 2SLGBTQ+ adults living in Toronto, Ontario, Canada, collected from March 2021 to July 2021. Participants were recruited using respondent-driven sampling to complete an internet-based survey including measures of psychological distress and minority stress. A subset of participants (n =50) completed a semi-structured qualitative interview to contextualize their mental health experiences during the COVID-19 pandemic.Results: Bivariate analysis revealed that self-reported anxiety (P= 0.029), depression (P = 0.001), perceived stress (P = 0.002), and somatic symptom scores (P = 0.014) were elevated among participants who reported living with family during the pandemic. These differences persisted in regression analysis adjusting for sexual identity, gender expression, race/ethnicity, age, citizenship, education, household size, and income. Discussion: Our findings offer important insights that will enable Toronto and other Canadian public health agencies to better respond to the needs of 2SLGBTQ+ and other vulnerable communities during ongoing COVID-19 pandemic and future health crises.

Pregnancy interventions represent key avenues for preventing non-communicable diseases, which, collectively, constitute a major global public health challenge. Evidence syntheses indicate that probiotic interventions, while effective in managing some pregnancy complications, do not confer health benefits to otherwise-uncomplicated pregnancies. Yet, messaging around probiotics in pregnancy is mixed, such that pregnant people may feel pressure to spend limited resources on (costly) probiotics. To tailor knowledge exchange and support safe, equitable access to pregnancy probiotics when their prescription may be warranted, we need to understand who takes probiotics during pregnancy and under what conditions.We used chi-square and logistic regression analyses of anonymous, cross-sectional survey data from 340 pregnant Canadians of diverse socio-demographic backgrounds to assess which respondents, by socio-demographic characteristics and pre-pregnancy/pregnancy health indicators, were relatively likely to: perceive probiotics as beneficial to pregnancy health and/or report taking probiotics during pregnancy. Forty-seven percent of respondents perceived probiotics as beneficial to pregnancy health; 51% reported consuming them. Probiotic attitudes and consumption were strongly socio-demographically-patterned, with higher-income, post-secondary-educated respondents disproportionately perceiving probiotics as healthy and taking them. There was no evidence of variation in probiotics attitudes or use by health indicators.Socio-economic factors may be more important determinants of pregnancy probiotic use in this sample than indications for pregnancy complications. We highlight the need to establish clear guidelines on pregnancy probiotics that reflect current evidence. We also call for facilitation of equitable access to probiotics for pregnant people when probiotics are likely to confer health benefits, to support long-term health and health equity.

Objectives: The causes of variation in breastfeeding duration in humans are poorly understood, but life history factors related to maternal energetics drive much of the variation in lactation duration in nonhuman animals. With this in mind, we investigated whether four energy-related factors influence variation in breastfeeding duration in a non-industrial human population: (1) mortality risk during mother's development (assessed via mother's adult height), (2) reliance on nutrientdense weaning foods, (3) access to and need for help with infant feeding and care ("allomaternal care"), and (4) maternal tradeoffs between current and future reproduction (measured via child's birth order).Materials and methods: The data pertain to 51 Kakchiquel-speaking Maya mothers and 283 children from a village in rural Guatemala. We developed a linear mixed model to evaluate the relationships between breastfeeding duration and the energy-related factors.Results: Duration of breastfeeding was associated with two of the energy-related factors in the ways we predicted but not with the other two. Contrary to predictions, taller mothers breastfed for shorter periods and we found no evidence that weanling diet quality impacts breastfeeding duration. As predicted, women who had more help with infants breastfed for shorter periods, and later-born infants breastfed longer than earlier-born ones.Discussion: The results regarding allomaternal care suggest that help reduces mothers' lactation demands. The energy saved may be redirected to increasing fecundity or investment in other children. The birth order result suggests that children born to mothers nearing reproductive senescence receive higher levels of investment, which likely impacts children's fitness.

Humans breastfeed our infants for less time than expected for primates of our size. Additionally, human breastfeeding duration appears more variable than in nonhuman species. This early and flexible weaning pattern affects maternal fertility as well as infant health and survivorship, from both within- and across- species perspectives. So, understanding what factors enabled humans to wean relatively early and flexibly is an important goal for human evolutionary demography. Yet, what these factors are and how they influence breastfeeding behaviour remain unclear. To address this gap, I present a series of three papers that each tests several hypotheses regarding influences on breastfeeding duration. The first paper reports a study that uses secondary data from small-scale human societies to investigate the effects of energetic factors on among-population variation in breastfeeding duration. The second has similar aims to the first, but uses within-population field data from indigenous Maya women from Guatemala to evaluate the energetic hypotheses. The third study, again using field data from Maya women, assesses a different set of hypotheses: that socio-ecological change and sources of socially-transmitted information about how to feed infants influence duration of breastfeeding.The first study shows that, across populations, breastfeeding duration associates negatively with maternal body mass, positively with maternal height, and negatively with dietary quality of weaning foods. The second indicates that within-population variation in breastfeeding duration associates negatively with maternal height, negatively with maternal access to help with infant care, and positively with parity. The last study suggests that duration of exclusive breastfeeding associates negatively with conservativeness of the source from which mothers learn about infant feeding behaviour. It also indicates that full duration of breastfeeding associates positively with household modernization. Taken together, these results suggest two things. One is that reduced duration of breastfeeding relates to greater maternal access to energy. The second is that socio-cultural factors influence variation in duration of breastfeeding in humans. These findings are consistent with previous claims that increases in energy availability and/or the development of complex cultural systems for information transmission contributed to the evolution of short, flexible breastfeeding and high fertility in humans.

The weaning process varies considerably among human populations, but it is not yet understood why this is the case. With this in mind, I used data from natural fertility societies to test two evolutionary theory-based hypotheses concerning variation in the timing of key events in the weaning process. First, I evaluated the null hypothesis that this variation simply reflects population history. I then tested the hypothesis that risk of resource failure affects weaning variation. Among-population variation in weaning behaviour is not correlated with the proxy I employed for population history and is only weakly correlated with some of the proxies for risk of resource failure. Thus, my analyses refute the population history hypothesis and provide only limited support for the risk hypothesis. Together, these results suggest that among-population variation in weaning behaviour is shaped by selection but, contrary to expectations, risk of resource failure is not the primary selector.