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It has long been suggested that environmental exposures (i.e., the exposome) play a dominant role in shaping trajectories of human aging and premature mortality. Here we aimed to quantify the contribution of the exposome and genome to aging and mortality. We conducted an exposome-wide analysis in the UK Biobank (n=492,567) to systematically identify exposures associated with mortality while accounting for exposure correlation and mismeasurement. We found that the exposome is a major mortality determinant irrespective of genetic disease risk via shaping distinct biological and multimorbidity patterns. We identified 41 independent exposures associated with mortality, and demonstrate that most identified exposures are associated with a common signature of age-related multimorbidity, aging biomarkers, and major cardiometabolic risk factors. Compared with age and sex, polygenic risk for 22 major diseases and aging phenotypes explained an additional 2% of mortality variation, whereas the exposome explained an additional 19%. While genetics explained the majority of variation in dementias and breast, prostate, and colorectal cancers, the exposome explained the majority of variation for diseases of the lung, heart, and liver. Our findings provide a comprehensive map of the contributions of environment and genetics to mortality and common age-related diseases.

This paper investigates the importance of women's physiological condition, alongside sociocultural factors, for predicting the risk of discontinuation of the injectable contraceptive due to side effects in Ethiopia. Contraceptive calendar data from the 2016 Ethiopian Demographic and Health Survey were analyzed. Women aged 15-49 who had initiated the injectable contraceptive in the last two years were included in the analysis (n = 1,513). Physiological factors investigated were body mass, iron status, reproductive depletion, and physical strain. After checking for reverse causality, associations between physiological and sociocultural risk factors and discontinuation due to side effects (DSE) or discontinuation due to other reasons (DOR) were estimated using multivariate Cox proportional regression analyses. Anemia status was associated with DSE, but not DOR. Anemic women were two times more at risk of DSE compared with nonanemic women (adjusted hazard ratios [aHR] = 2.38, confidence interval [CI] = 1.41-4.00). DOR was predicted by religion, wealth, and relationship status. Accounting for diversity in physiological condition is key for understanding contraceptive discontinuation due to side effects. To reduce side effects, family planning programs might benefit from providing hormonal contraception within an integrated package addressing anemia.

Background Matriliny is a kinship structure where descent is traced through the female line. In these societies, individuals recognize their matrilineal kin (i.e., kin related trough their mothers), and belong to their mother’s clan. Matrilineal descent rule often goes with inheritance rules, whereby wealth can be transmitted either from father and mother to daughters, from mother’s brother to his sister’s son, or from mother’s brother and mother to her offspring (S. M. Mattison, 2011). Moreover, matriliny is often associated with matrilocal postmarital residence (Aberle, 1961), where the married couple resides with the wife’s descent group (S. M. Mattison, 2016) and/ or in her natal household. The idea that matriliny favours women is an age-old one in anthropology. Morgan (Morgan, 1877), who studied the Iroquois, and later Engels (Engels, 1902), even assimilated matriliny and matriarchy. Further evidences suggest instead that not only matriarchy (female monopolization of political power) is scarce, but when they inherit, the actual management of the inheritance is shared in the hands of male authorities (her uncle, her brother). As Lévi-Strauss (Lévi-Strauss, 1967) put it: “The woman is never anything more than the symbol of her lineage. Matrilineal descent is the authority of the woman's father or brother extended to the brother-in-law's village.” (p.117). The greatest political and economic power of women in matrilineal societies has thus been qualified since Engels. Although they have little institutional and political power, matrilineal women play a key role in lineage organization. They are often the guardians of religious ceremonies and rituals related to the ancestors, important duties that command respect. When they inherit property, matrilineal women also enjoy greater intrahousehold bargaining power and are less reliant on their husbands’ material resources. They can more freely make decision regarding household purchases and health expenditures (Lowes, 2022), with positive effects on their own health as well as their children’s. In Peru, ownership rights given to women was associated with a decrease in birth rate compared with households that did not benefit from the titling program (Field, 2013), suggesting that when women get ownership rights, their bargaining power increases and they can more easily impose their reproductive choices. Finally, matrilineal women benefit from their kin support, either because they live with them, or because they keep close to other members of the matriclan. Proximity with their kin allow women to be supported in case of spousal conflicts or domestic violence: women in the African matrilineal belt are less likely to justify and report domestic violence than their patrilineal counterpart (Lowes, 2020). Similarly, among the Khasi, women who live with their mothers can impose their reproductive agenda (i.e. their pregnancy rate) rather than following that of their husbands, resulting in older age at first birth and better child survival rate for women co-living with their mothers (Leonetti et al., 2007). This result suggests a protective role of the mother to preserve maternal investment made in her daughter, that contrasts with husbands’ interest to multiply the number of offspring. Besides, kin are preferred cooperation partners with whom to share domestic chores, childrearing and resources in case of need. In low- and middle-income countries where climate hazards expose people to yields variation, economic support from kin is crucial (Banerjee & Duflo, 2012). Moreover, as they are expected to look after their parents and non-married kin, parents, especially in countries that do not have pension system, invest more in their education (Bau, 2021). Differences between patrilineal and matrilineal systems have important consequences for gender gaps in health, psychological and political domains. In the Meghalaya (India) where patrilineal tribes live nearby matrilineal, the latter exhibit fewer gender differences on political engagement and preferences over social policies than the former (Brule & Gaikwad, 2020; Robinson & Gottlieb, 2021). At the behavioural level, women’s behaviours regarding competition, cooperation and time preference have proven to be closer to men’s behaviours in several matrilineal relative to patrilineal societies (Ellena & Nongkynrih, 2017; Gneezy et al., 2009; Gong & Yang, 2012). Among the Mosuo of China, the gender gap in centrality and social network density also closes in matrilineal context (S. Mattison et al., 2021) as well as risk of inflammation and type II diabetes (Reynolds et al., 2020). More recently, Chen et al. (Chen et al., 2023) found that southwest Chinese individuals who stay in their natal home at marriage have less workload (measured as step counts) than those who disperse, providing further evidence that matrilocality allows women to reduce household chores. Aim of the study We will focus on the effect of matrilineal kinship on women’s health. Matrilineal norms structure social ties and distribution of inheritance, either of which could differently affect women’s health. Kin ties are moreover not expected to have the same effect on health depending on area features (urban/ rural, economic development). The current study aims to clarify mechanisms and socio-economic conditions by which matrilineal kinship improves women’s health among matrilineal women in Meghalaya (India). The diversity of inheritance transmissions, post-marital residence and economic development patterns allow to disentangle their respective effect on health. We will use data from the Demographic and Health Surveys (DHS) conducted in India in 2015. Our sample includes all data available in the Meghalaya, a state inhabited by 3 mains matrilineal tribes; and variables about women’s health (anthropometrics, anaemia), household features (matrilocal, neolocal, patrilocal), gender of the ownership of house within the household, geographical covariates at the cluster level. We will use household decision-making variables and gender gap in education to test causal pathways of the relationship between matriliny and women’s health. Research questions 1) How does proximity with kin and material ownership affect women’s health? 2) Does the effect of matriliny on women's health depend on economic development in the area? 3) Among women living with their kin, is the share of female kin (compared with male kin) positively associated with their health?

The issue of “rumours” around contraceptive side-effects is critical for explaining contraceptive prevalence. In fact, most contraceptive discontinuation ‘whilst in need of contraception’ is due to contraceptive side-effects (Ali, Cleland and Shah, 2012). Yet, there has been no micro-level study into the cultural transmission of the experience and/or fear of contraceptive side-effects, significantly limiting our understanding of the cultural evolution of modern contraception. The project we are proposing will take the first step in this direction, being the first to experimentally test many of the hypotheses from the cultural evolution literature and how these hold in the context of contraception. While the field of cultural evolution has focused on adoption dynamics, there is a pressing need to study the cultural transmission of contraceptive discontinuation, a key determinant of unwanted fertility (Alvergne and Stevens, 2021). Fear of side-effects when using hormonal contraception appears to be prevalent for all methods and all groups of society (Wells, 2015), suggesting that contraceptive discontinuation due to side-effects is culturally transmitted. Yet, the cultural selection processes (i.e. the spread between individuals), of these contraceptive side-effects are unknown. Using transmission chain experiments (a common method to understand the spread of cultural information, such as rumours, (Mesoudi, Whiten and Dunbar, 2006)), we will evaluate the importance of (i) social learning context-biases (i.s., the tendency to learn from specific models such as prestigious individuals or experts) and (ii) social learning content-bias (the tendency to be attracted to some types of rumours over others, given its relevance to biological fitness). By developing cultural evolution methods tailored to the issue of contraception, this project will produce the proof of concept needed to build a research program on the cultural evolution of contraceptive behaviour. Our interest in understanding the transmission of rumours about contraceptive side-effects is two-fold. Firstly, from a public health perspective, understanding the factors that impact the spread of rumours around contraceptive side effects can help to formulate a more targeted approach to address false rumours. Secondly, in terms of cultural evolution, this study may help us to further understand cultural attitudes towards contraception, human reproductive decisions and the inherent biases that exist around these. Through specifically testing the impact of cultural transmission of fitness and non-fitness related side effects, we can also examine whether culture has taken attitudes towards contraception down a route that aligns with what we would expect from Darwinian evolution. This study will use transmission chain experiments to study the cultural transmission of information of contraceptive side effect information. We will create a number of transmission chains each of which with three generations. Participants will be presented with a short text (approx. 200 words), composed of three main paragraphs, each with a different class of rumour. In this case we define a rumour as a piece of information that is passed between individuals without clear evidence or confirmation of its truth or accuracy. Participants will be asked to read the text and then to reproduce the information they read, from memory, as if they were passing the information on to someone else. The next individual within a chain will then receive the text that another person has produced from memory, and the same will happen for the third generation. As a result, we will be able to see how the content has changed over three generations. Overall, this study will be the first step in deepening our understanding of the role that rumours may have in underpinning population-level change in the frequency of contraceptive uptake, i.e., the cultural evolution of modern contraception. It is hoped that this study will pave the way for similar transmission chain studies to be used to model the spread of information concerning health side effects and other cultural traits. References Ali, M.M., Cleland, J.G., Shah, I.H. and World Health Organization, 2012. Causes and consequences of contraceptive discontinuation: evidence from 60 demographic and health surveys. Alvergne, A. and Stevens, R., 2021. Cultural change beyond adoption dynamics: Evolutionary approaches to the discontinuation of contraception. Evolutionary Human Sciences, 3, p.e13. Mesoudi, A., Whiten, A. and Dunbar, R., 2006. A bias for social information in human cultural transmission. British journal of psychology, 97(3), pp.405-423. Wells, E., 2015. Countering myths and misperceptions about contraceptives. Seattle: PATH.

Analysis of the 2016 Ethiopian Demographic and Health Survey to investigate whether factors associated with naturally low reproductive hormone levels predict contraceptive discontinuation due to side-effects among women who have used the injectable contraceptive in the last year.

An analysis into whether a relationship exists between age at natural menopause and cumulative number of lifetime menstrual cycles within the UK Biobank cohort.

Worldwide, there is significant variation in population twinning rates, however the influence of ecological factors for explaining this variation remains unclear. The influence of maternal factors such as maternal age, parity, genotype and various anthropomorphic measures on twinning has extensively been studied. However, environmental factors have yet to be linked to variation in twinning rates between regions. This study aims to test the hypothesis that twinning rates may respond to under-5 child mortality risk in the population. Data on births will be derived from Demographic and Health Surveys in 30 Sub-Saharan Africa countries. Descriptive and inferential statistical analyses will be used to influence of the national under-5 mortality risk on twinning rates.

In women, the menstruation process can be accompanied by debilitating symptoms, such as dysmenorrhea (painful periods), which are still poorly understood and has a major impact on the quality of life of the women concerned . The rate of dysmenorrhoea is 16.8 to 81% (according to Latthe et al., 2006), it is the most common gynaecologic problem in women of all ages and origins. Here we explore the role of Sexual Transmitted Infections (STI) in dysmenorrhea, as well as the impact of sexual activity in this context, known to influence cyclical immunity.

International audience; Background: Three hundred fifty million people worldwide suffer from underactive thyroid conditions, which can lead to infertility, obesity, heart disease, and impaired mental health when poorly managed. Although mobile health (mHealth) applications can be a useful solution for self-managing one's condition, the impact of digital solutions for improving the health of thyroid patients remains unknown. Methods: We used a mixed methods analysis to assess the ways in which a digital approach might benefit thyroid patients. A cross-sectional study was conducted among users of BOOST Thyroid, an mHealth application for patients with an underactive thyroid. We collected data using a modified Short Form 36 Health Survey Questionnaire to measure the impact of in the app on participants' perceived health and quality of life. Participants were asked to (1) score their quality of life before and after using the app, and (2) describe whether and how using the app helped them. Results: We enrolled 406 users (380 females and 26 males), aged 18-78 years. Most participants (95.8%) reported using the app was helpful; of which 68% reported it improved their quality of life and 70.8% reported it had a positive impact on their health. Participants who found the app useful experienced less symptoms and a lower intensity of remaining symptoms. A key factor reported by these participants as helping with managing their health is the information provided in the app. Conclusions: The results support the idea that a patient-centered treatment would benefit from including mHealth tools for a daily self-management of underactive thyroid condition, as it can increase health literacy and improve both one's health status and quality of life.

The discourse around menstrual cycles is often pathologised, leading to negative perceptions of menstruation. The extent to which premenstrual syndrome (PMS) is inherently negative or the result of medicalised framing has long remained unclear. We address this gap by investigating whether framing the premenstrual experience as being both negative and positive components would enable individuals to report more diverse and positive experiences than are currently reported. In an online experiment, 2,638 participants were randomly allocated to one of three question phrasings (control: describe your premenstrual experience; treatment one: describe your positive and negative premenstrual experience; treatment two: describe your negative and positive premenstrual experience). Sentiment analysis was applied to responses to create polarity scores. A two-part Bayesian model was performed to investigate the effect of phrasing in predicting differences in polarity scores. Across all phrasings, responses were negatively skewed. However, response polarity scores and diversity of symptoms were higher if the question specified both positive and negative experiences compared to the control group. This corroborates previous literature showing that a negative premenstrual phase is a widespread phenomenon but challenges the idea that the premenstrual experience is solely negative. The findings have implications for how the premenstrual experience is quantified.

International audience; Culture is often invoked as an explanation for disparities in health or as a barrier to success in population health interventions, yet the micro-level processes underpinning cultural inertia and cultural epidemics are rarely unpacked. By contrast, a cultural evolution framework breaks down “culture” as a population of cultural variants and focuses on uncovering the social learning “strategies” and individual motivations leading to behavioural variation and change. Here I elaborate on how thinking evolutionarily can help understand the bidirectional relationship between behaviour and culture, thereby shedding light on the processes leading to the adoption, transmission, and maintenance of behaviour over time and across socio-ecological contexts. I begin with introducing the concept of culture in epidemiology as well as contemporary evolutionary approaches to culture. I then consider how a cultural evolution framework can be deployed at various levels of interventions, from health-message framing and norms-based messaging to social network and communities-based interventions. Lastly, I evaluate how a cultural evolution framework can be harnessed to tackle public health challenges, including how to seed a new healthy behaviour, how to spread behaviour beyond its initial uptake and how to maintain behaviour in the face of changing ecologies. While cultural evolution (CE) studies of population health (PH) issues are currently limited, there is a large scope for CE and PH to mutually benefit from joining forces.