No abstract

No abstract

Biologists use genetic relatedness between family members to explain the evolution of many behavioural and developmental traits in humans, including altruism, kin investment and longevity. Women's postmenopausal longevity in particular is linked to genetic relatedness between family members. According to the 'grandmother hypothesis', post-menopausal women can increase their genetic contribution to future generations by increasing the survivorship of their grandchildren. While some demographic studies have found evidence for this, others have found little support for it. Here, we re-model the predictions of the grandmother hypothesis by examining the genetic relatedness between grandmothers and grandchildren. We use this new model to re-evaluate the grandmother effect in seven previously studied human populations. Boys and girls differ in the per cent of genes they share with maternal versus paternal grandmothers because of differences in X-chromosome inheritance. Here, we demonstrate a relationship between X-chromosome inheritance and grandchild mortality in the presence of a grandmother. With this sex-specific and X-chromosome approach to interpreting mortality rates, we provide a new perspective on the prevailing theory for the evolution of human female longevity. This approach yields more consistent support for the grandmother hypothesis, and has implications for the study of human evolution.

Acculturation represents an important construct for elucidating the determinants and consequences of health disparities in minority populations. However, the processes and mechanisms underlying acculturation’s effects on health are largely undetermined and warrant further study. We integrate concepts from anthropology and statistics to describe the role of sociocultural context as a putative modifier of the relationship between acculturation and health. Sociocultural context may influence the extent to which exposure to host culture leads to internalization of host cultural orientation, and may influence the extent to which acculturation leads to stress and adoption of unhealthy behaviors. We focus on specific aspects of sociocultural context: (1) neighborhood ethno-cultural composition; (2) discrimination; (3) discrepancy between origin and host environments; (4) discrepancy between heritage and host cultures; (5) origin group, host group, and individual attitudes towards assimilation; (6) variation in targets of assimilation within host community; (7) public policy and resources; (8) migration selection bias. We review and synthesize evidence for these moderation effects among first- and later-generation immigrants, refugees, and indigenous populations. Furthermore, we propose best-practices data-collection and statistical-analysis methods for this purpose, in order to improve our understanding of the complex, multilevel aspects of the relationship between acculturation and health.

Acculturation represents an important construct in the context of health disparities. Although several studies have reported relationships between various aspects of acculturation and health in minority populations, crucial inconsistencies remain. One likely reason for these inconsistencies may relate to limitations in the conceptualization and operationalization of acculturation, particularly in the context of health research. The acculturation construct underwent major conceptual and operational change when it was adapted from anthropology to psychology, and we argue another major shift is now required for use of this construct in health research. Issues include determining whether acculturation measures should focus on an individual’s internal attitudes or overt behaviors; whether they should characterize cultural orientation status at a given point in time or change over time; whether measures should be culture-specific or more global in nature; how the issue of multiculturalism should be addressed; how measures can optimally incorporate multiple dimensions of acculturation; and whether proxy measures should be used. These issues are important in the context of health research because of their implications for determining the direct and indirect effects of cultural change on health-related biological and behavioral processes. We elaborate on and address each of these issues from a perspective that spans multiple disciplines across the biological and social sciences, and offer concrete recommendations with the ultimate goal of achieving a better understanding of the role of acculturation in minority health and health disparities.