Men's physical health and life history transitions in the Philippines: Evidence for 'marital selection' but not protective effects of partnering and fatherhood.

In Euro-American societies, married people typically have lower overall risks for total mortality and for certain chronic conditions compared to non-married people. However, people becoming partnered and parents also tend to gain weight in Euro-American settings. Few studies have tested whether links between physical health and life history status translate to other cultural contexts where the socio-ecological dynamics of family life may differ. This limits the application of these insights to men's well-being in global public health. To help address this gap, we drew on a large, long-running birth cohort study of Filipino men, using data collected at three waves between 2005 and 2014 when men were 21.5-30.5 years old (N = 607, obs. = 1760). We tested for the effects of the transition to partnering (marriage/cohabitation) and fatherhood on men's physical health (waist circumference, fat-free mass index, and grip strength). Men becoming partnered or partnered fathers (P/PF) had comparable longitudinal physical health trajectories to men remaining single non-fathers. However, men who became P/PF by their mid 20s had higher fat-free mass index values than single non-fathers at each wave, with the largest effect observed when all men were single non-fathers at baseline. Men who became P/PF by their early 30s were also stronger than the reference group at baseline. Thus, men who were more muscular and stronger at baseline were more likely to transition to P/PF status, consistent with a 'marital selection' model. In complementary analyses, men did not exhibit adverse health effects when they became partnered fathers as young adults or parents to infants, respectively. These findings suggest that links between health and life history transitions in this setting differ from those commonly observed in Euro-American societies. While transitions to marriage and fatherhood are promising windows for interventions to improve men's health, our results highlight the importance of tailoring such approaches to local dynamics.

Evidence for an adolescent sensitive period to family experiences influencing adult male testosterone production.

Across vertebrates, testosterone is an important mediator of reproductive trade-offs, shaping how energy and time are devoted to parenting versus mating/competition. Based on early environments, organisms often calibrate adult hormone production to adjust reproductive strategies. For example, favorable early nutrition predicts higher adult male testosterone in humans, and animal models show that developmental social environments can affect adult testosterone. In humans, fathers' testosterone often declines with caregiving, yet these patterns vary within and across populations. This may partially trace to early social environments, including caregiving styles and family relationships, which could have formative effects on testosterone production and parenting behaviors. Using data from a multidecade study in the Philippines (n = 966), we tested whether sons' developmental experiences with their fathers predicted their adult testosterone profiles, including after they became fathers themselves. Sons had lower testosterone as parents if their own fathers lived with them and were involved in childcare during adolescence. We also found a contributing role for adolescent father­son relationships: sons had lower waking testosterone, before and after becoming fathers, if they credited their own fathers with their upbringing and resided with them as adolescents. These findings were not accounted for by the sons' own parenting and partnering behaviors, which could influence their testosterone. These effects were limited to adolescence: sons' infancy or childhood experiences did not predict their testosterone as fathers. Our findings link adolescent family experiences to adult testosterone, pointing to a potential pathway related to the intergenerational transmission of biological and behavioral components of reproductive strategies.

Neither environmental unpredictability nor harshness predict reliance on alloparental care among families in Cebu, Philippines.

Alloparental caregiving is key to humans' highly flexible reproductive strategies. Across species and across societies, alloparental care is more common in harsh and/or unpredictable environments (HUEs). Currently, however, it is unclear whether HUEs predict intra-population variation in alloparental care, or whether early life HUEs might predict later alloparental care use in adulthood, consistent with adaptive developmental plasticity. We test whether harshness measures (socioeconomic status (SES), environmental hygiene, crowding) and unpredictability measures (parental unemployment, paternal absence, household moves) predicted how much alloparental assistance families in Cebu, Philippines received, in a multigenerational study with data collected across four decades. Though worse environmental hygiene predicted more concurrent alloparental care in 1994, we found little evidence that HUEs predict within-population variation in alloparental care in this large-scale, industrialized society. Indeed, less-crowded conditions and higher SES predicted more alloparental care, not less, in the 1980s and in 2014 respectively, while paternal absence in middle childhood predicted less reliance on alloparental care in adulthood. In this cultural context, our results generally do not provide support for the translation of interspecific or intersocietal patterns linking HUEs and alloparental care to intra-population variation in alloparental care, nor for the idea that a reproductive strategy emphasizing alloparental care use may be preceded by early life HUEs.

Changes in asset-based wealth across the life course in birth cohorts from five low- and middle-income countries.

BACKGROUND: Temporally-harmonized asset-based measures of wealth can be used to study the association of life-course wealth exposures in the same scale with health outcomes in low- and middle-income countries (LMICs). The within-individual longitudinal stability of asset-based indices of wealth in LMICs is poorly understood. METHODS: Using data from five birth cohorts from three continents, we developed temporally-harmonized asset indices over the life course through polychoric principal component analysis of a common set of assets collected consistently over time (18 years in Brazil to 50 years in Guatemala). For each cohort, we compared the harmonized index to cross-sectional indices created using more comprehensive asset measures using rank correlations. We evaluated the rank correlation of the harmonized index in early life and adulthood with maternal schooling and own attained schooling, respectively. RESULTS: Temporally-harmonized asset indices developed from a consistently-collected set of assets (range: 10 in South Africa to 30 in Philippines) suggested that mean wealth improved over time for all birth cohorts. Cross-sectional indices created separately for each study wave were correlated with the harmonized index for all cohorts (Brazil: r = 0.78 to 0.96; Guatemala: r = 0.81 to 0.95; India: 0.75 to 0.93; Philippines: r = 0.92 to 0.99; South Africa: r = 0.84 to 0.96). Maternal schooling (r = 0.15 to 0.56) and attained schooling (r = 0.23 to 0.53) were positively correlated with the harmonized asset index in childhood and adulthood respectively. CONCLUSIONS: Temporally-harmonized asset indices displayed coherence with cross-sectional indices as well as construct validity with schooling.

Fatherhood and psychobiology in the Philippines: Perspectives on joint profiles and longitudinal changes of fathers' estradiol and testosterone.

OBJECTIVES: Research on the psychobiology of partnering and fathering has focused on testosterone (T), oxytocin, and prolactin (PRL) as mechanisms that potentially mediate life history trade-offs related to those roles. Less is known about other hormones that might be responsive to life history transitions and implicated in fathering, such as estradiol (E2). We examined how E2 changed during the transition to marriage and fatherhood, its correlation with fathers' caregiving, and its joint within-individual production with other hormones (T, PRL). METHODS: Data were collected from a total of 913 Filipino men (aged 25.9 years ± 0.3 SD at follow-up) enrolled in a longitudinal cohort study. Morning saliva samples collected at baseline (2005) and follow-up (2009) were assayed for T and E2 (n = 329), dried blood spots from baseline were assayed for PRL. Fathers reported on caregiving in 2009. RESULTS: When compared with men who remained single non-fathers over the study period, men who became married residential fathers experienced larger declines in E2. This effect was non-significant when we controlled for longitudinal changes in T. E2 was not significantly related to fathers' caregiving, controlling for T. In cross-sectional analyses for PRL, T, and E2, married residential fathers exhibited within-individual profiles of reduced T and elevated PRL, whereas single non-fathers exhibited the opposite profile of elevated T and reduced PRL. CONCLUSIONS: Our findings point to the need for future research to consider the mutually regulatory dynamics and/or combinatorial implications of multiple physiological axes acting within individuals to underpin life history trade-offs and behavioral strategies.

Exploring the links between early life and young adulthood social experiences and men's later life psychobiology as fathers.

Early life cues of environmental harshness and unpredictability have been hypothesized to influence within-species variation in the timing of life history transitions and the dynamics of reproductive strategies, such as investments in mating and parenting. It is also believed that adolesence is an influential developmental period for male reproductive strategies, with those who achieve greater social and sexual success during that period maintaining faster life history strategies into adulthood. If correct, such early life and post-pubertal experiences could also help shape the psychobiological pathways that mediate reproductive strategies, including the well documented physiological shifts that occur when some men become parents. Drawing on a large sample of Filipino men (n=417), we evaluate whether men who experienced cues of harshness or unpredictability in childhood or have earlier ages at sexual debut have elevated testosterone (T) as fathers. We also test whether males who experienced a combination of early life experiences of harshness or unpredictability and had earlier ages of sexual debut during adolescence had the most elevated T as fathers. We found that fathers who experienced early life harshness and who engaged in sex at an earlier age had elevated waking T. Among men transitioning to fatherhood across the 4.5-year follow-up period of this study, those who experienced unpredictability and who engaged in sex at an earlier age showed attenuated declines in waking T between baseline and follow-up. Complementing these findings, we found that fathers who first engaged in sex at later ages had greater acute declines in T when they played with their toddlers. We suggest that these patterns could reflect programming effects of sociosexual experiences during the years following the marked biological transitions that accompany puberty, which occur along with the better-studied effects of earlier life exposures to stressors. Overall, our results support the hypothesis that early life circumstances and social and sexual experiences, from early life to young adulthood, help calibrate physiological axes as key mechanisms coordinating dynamic life history strategies.

The role of testosterone in coordinating male life history strategies: The moderating effects of the androgen receptor CAG repeat polymorphism.

Partnered fathers often have lower testosterone than single non-parents, which is theorized to relate to elevated testosterone (T) facilitating competitive behaviors and lower T contributing to nurturing. Cultural- and individual-factors moderate the expression of such psychobiological profiles. Less is known about genetic variation's role in individual psychobiological responses to partnering and fathering, particularly as related to T. We examined the exon 1 CAG (polyglutamine) repeat (CAGn) within the androgen receptor (AR) gene. AR CAGn shapes T's effects after it binds to AR by affecting AR transcriptional activity. Thus, this polymorphism is a strong candidate to influence individual-level profiles of "androgenicity." While males with a highly androgenic profile are expected to engage in a more competitive-oriented life history strategy, low androgenic men are at increased risk of depression, which could lead to similar outcomes for certain familial dynamics, such as marriage stability and parenting. Here, in a large longitudinal study of Filipino men (n=683), we found that men who had high androgenicity (elevated T and shorter CAGn) or low androgenicity (lower T and longer CAGn) showed elevated likelihood of relationship instability over the 4.5-year study period and were also more likely be relatively uninvolved with childcare as fathers. We did not find that CAGn moderated men's T responses to the fatherhood transition. In total, our results provide evidence for invested fathering and relationship stability at intermediate levels of androgenicity and help inform our understanding of variation in male reproductive strategies and the individual hormonal and genetic differences that underlie it.