Partners in Health: Investigating Social Genetic Effects Among Married and Cohabiting Couples.

Partners resemble each other in health behaviors and outcomes such as alcohol use, smoking, physical activity, and obesity. While this is consistent with social contagion theory suggesting partner influence, it is notoriously difficult to establish causality because of assortative mating and contextual confounding. We offer a novel approach to studying social contagion in health in long-term partnerships by combining genetic data of both partners in married/cohabiting couples with longitudinal data on their health behaviors and outcomes. We examine the influence of the partner's genetic predisposition for three health outcomes and behaviors (BMI, smoking, and drinking) among married/cohabiting couples. We use longitudinal data from the Health and Retirement Study and the English Longitudinal Study of Ageing with data on health outcomes and genotypes for both partners. Results show that changes over time in BMI, smoking, and drinking depend on the partner's genetic predispositions to these traits. These findings underline the importance of people's social surroundings for their health and highlight the potential of targeting health interventions at couples.

Transmissible Mycobacterium tuberculosis Strains Share Genetic Markers and Immune Phenotypes.

RATIONALE: Successful transmission of tuberculosis depends on the interplay of human behavior, host immune responses, and Mycobacterium tuberculosis virulence factors. Previous studies have been focused on identifying host risk factors associated with increased transmission, but the contribution of specific genetic variations in mycobacterial strains themselves are still unknown. OBJECTIVES: To identify mycobacterial genetic markers associated with increased transmissibility and to examine whether these markers lead to altered in vitro immune responses. METHODS: Using a comprehensive tuberculosis registry (n = 10,389) and strain collection in the Netherlands, we identified a set of 100 M. tuberculosis strains either least or most likely to be transmitted after controlling for host factors. We subjected these strains to whole-genome sequencing and evolutionary convergence analysis, and we repeated this analysis in an independent validation cohort. We then performed immunological experiments to measure in vitro cytokine production and neutrophil responses to a subset of the original strains with or without the identified mutations associated with increased transmissibility. MEASUREMENTS AND MAIN RESULTS: We identified the loci espE, PE-PGRS56, Rv0197, Rv2813-2814c, and Rv2815-2816c as targets of convergent evolution among transmissible strains. We validated four of these regions in an independent set of strains, and we demonstrated that mutations in these targets affected in vitro monocyte and T-cell cytokine production, neutrophil reactive oxygen species release, and apoptosis. CONCLUSIONS: In this study, we identified genetic markers in convergent evolution of M. tuberculosis toward enhanced transmissibility in vivo that are associated with altered immune responses in vitro.

Acceptance of homosexuality through education? Investigating the role of education, family background and individual characteristics in the United Kingdom.

Higher educated people tend to be more accepting of homosexuality than lower educated people. This has inspired claims that education leads to a higher acceptance of homosexuality. Alternatively, the association between education and acceptance of homosexuality could be confounded by (un)observed family background and stable individual characteristics. This study investigated the association between education and acceptance of homosexuality and the role of potential confounders in a unique longitudinal sample of British siblings. Multilevel and fixed effects analyses show that both perspectives apply. A large part of the association between education and acceptance of homosexuality could be attributed to family background and observed individual characteristics (one third), as well as unobserved individual characteristics (an additional third), but the positive association remains. Findings are discussed in light of existing explanations regarding the effect of education on the acceptance of homosexuality.

Is the Association Between Education and Fertility Postponement Causal? The Role of Family Background Factors.

A large body of literature has demonstrated a positive relationship between education and age at first birth. However, this relationship may be partly spurious because of family background factors that cannot be controlled for in most research designs. We investigate the extent to which education is causally related to later age at first birth in a large sample of female twins from the United Kingdom (N = 2,752). We present novel estimates using within-identical twin and biometric models. Our findings show that one year of additional schooling is associated with about one-half year later age at first birth in ordinary least squares (OLS) models. This estimate reduced to only a 1.5-month later age at first birth for the within-identical twin model controlling for all shared family background factors (genetic and family environmental). Biometric analyses reveal that it is mainly influences of the family environment-not genetic factors-that cause spurious associations between education and age at first birth. Last, using data from the Office for National Statistics, we demonstrate that only 1.9 months of the 2.74 years of fertility postponement for birth cohorts 1944-1967 could be attributed to educational expansion based on these estimates. We conclude that the rise in educational attainment alone cannot explain differences in fertility timing between cohorts.

Genetic influence on age at first birth of female twins born in the UK, 1919-68.

Using a sample of monozygotic (945, 42 per cent) and dizygotic (1,329, 58 per cent) twin pairs born 1919-68 in the UK, we applied innovative tobit models to investigate genetic and environmental influences on age at first birth (AFB). We found that a substantial part (40 per cent) of the variation in AFB is caused by latent family characteristics. Genetic dispositions (26 per cent) play a more important role than the shared environment of siblings (14 per cent), with the non-shared environment/measurement error having the strongest influence (60 per cent). Like previous studies, this study reveals marked changes in estimates over time, and supports the idea that environmental constraints (war or economic crisis) suppress and normative freedom (sexual revolution) promotes the activation of genetic predispositions that affect fertility. We show that the exclusion of censored information (i.e., on the childless) by previous studies biased their results.

Do mother's and father's education condition the impact of parental divorce on child well-being?

We use the British Cohort Study to investigate to what extent parental resources moderate the association between parental divorce in childhood and lowered child well-being as indicated by maternal reports of child psychological well-being and by academic test scores (reading and math tests). We argue that children of mothers with more years of education suffer less when their parents split up because better educated mothers may be better able to provide a safe and stable environment for their children after divorce. In addition, we argue that having a better educated father could either aggravate or reduce the effects of parental divorce. This is one of the first studies to simultaneously investigate the role of maternal, and paternal resources, and pre-divorce shared resources. Our analyses indicate that the effect of parental divorce on psychological well-being is reduced for better educated mothers and for families with more pre-divorce economic resources, but increased for better educated fathers. For academic test scores we find a protective effect of having a better educated father and higher pre-divorce social resources.

Low induction of proinflammatory cytokines parallels evolutionary success of modern strains within the Mycobacterium tuberculosis Beijing genotype.

One of the most widespread clades of Mycobacterium tuberculosis worldwide, the Beijing genotype family, consists of ancient (atypical) and modern (typical) strains. Modern Beijing strains outcompete ancient strains in terms of prevalence, while reserving a higher degree of genetic conservation. We hypothesize that their selective advantage lies in eliciting a different host immune response. Bead-disrupted lysates of a collection of different M. tuberculosis strains of the modern (n = 7) or ancient (n = 7) Beijing genotype, as well as the Euro-American lineage (n = 6), were used for induction of ex vivo cytokine production in peripheral blood mononuclear cells (PBMCs) from 10 healthy individuals. Hierarchical clustering and multivariate regression analyses were used to study possible differences in production of nine cytokines. Modern and ancient M. tuberculosis Beijing genotypes induced different cytokine signatures. Overall induction of interleukin-1ß (IL-1ß), gamma interferon (IFN-γ), and IL-22 was 38 to 40% lower after stimulation with modern Beijing strains (corrected P values of <0.0001, 0.0288, and 0.0002, respectively). Euro-American reactivation strains induced 2-fold more TNF-α production than both types of Beijing strains. The observed differences in cytokine induction point to a reduction in proinflammatory cytokine response as a possible contributing factor to the evolutionary success of modern Beijing strains.

Worksite health promotion for employees working from home: A vignette experiment examining intentions to participate.

This study explores which factors affect employees' intention to participate in worksite health promotion (WHP) when they work from home. Employees increasingly work from home, yet existing WHP is mainly tied to the workplace. We lack knowledge on what might stimulate employees to make use of WHP specifically when they work from home. Drawing on the theory of reasoned action, we studied whether type of activity, duration, if WHP takes place during work time, how often employees work from home (shaping employees' attitude) and colleague participation (social norms) explain employees' intention to participate in WHP when working from home. To do so, we employed a vignette experiment. Results show that employees' intentions are higher for walking and taking breaks than for an online sports class. Moreover, intentions are higher for shorter activities and when participating in WHP can be done during work time. The more colleagues participate, the higher intentions of employees to do so too. By offering WHP for employees at home, employers can promote employees' health even when these are not present in the workplace. Our study provides leads into how employers may create conditions under which employees use WHP when working from home.

Worksite Health Promotion and Work Performance: Both Awareness and Use Matter.

OBJECTIVE: This work aimed to study whether being aware of the existence of worksite health promotion (WHP), using it, or both are related to employees' task and contextual performance. METHODS: Multilevel cross-sectional data came from the European Sustainable Workforce Survey, with data from more than 11,000 employees in 259 organizations. Generalized structural equation modeling was used to examine two types of WHP: healthy menus and sports facilities. RESULTS: Awareness of healthy menus and sports facilities was positively associated with task and contextual performance. Healthy menus use was related to both higher task and contextual performance, whereas sports facilities use was only associated with contextual performance. The relation of WHP use was stronger for contextual than for task performance. CONCLUSIONS: Organizations should ensure that employees are aware of the availability of WHP as well as stimulate employees to make use of it.

Actions Speak Louder Than Words: Workplace Social Relations and Worksite Health Promotion Use.

OBJECTIVE: To study whether workplace social relations explain use of worksite health promotion (WHP), by examining colleagues' and team managers' WHP encouragement of a healthy lifestyle, and colleague WHP uptake. METHODS: Multilevel data came from the second wave of the European Sustainable Workforce Survey (4345 employees of 402 team in 9 countries). Linear probability models were used to test use of two types of WHP: healthy menus and sport facilities. RESULTS: Employees are more likely to use healthy menus and sport facilities when more colleagues do so too and when colleagues encourage a healthy lifestyle. Surprisingly, encouragement by one's manager plays no role. CONCLUSIONS: Social contact among colleagues can facilitate WHP use, and WHP initiatives should pay attention to the influential role of colleagues.

Worksite health promotion and social inequalities in health.

It is well-documented that higher educated employees have better health than the lower educated. The workplace has been put forward as a contributor to this inequality. We extend previous work on workplace characteristics that could influence employee health by asking to what extent workplace health promotion (WHP) can account for the relation between education and health. Two ways in which WHP may relate to health inequalities are addressed: higher educated employees may be more likely to use WHP than lower educated employees and the effect of WHP on health may be stronger for higher educated than for lower educated employees. Using data from the European Sustainable Workforce Survey which contains information on over 11000 employees in 259 organisations, we test whether three types of WHP mediate or moderate the relation between education and health: healthy menus, sports facilities and health checks. We find that higher educated employees are in better health and that use of WHP positively relates to health. Use of healthy menus and sports facilities in the workplace can contribute to increasing health inequalities, as lower educated employees are less likely to make use of these. Health checks could contribute to diminishing health inequalities, as lower educated employees are more likely to use them compared to higher educated employees. The effect of WHP is not contingent on education. We advise stimulating lower educated employees to make more use of WHP, which can contribute to decreasing health inequalities.

The effects of prenatal exposure to Ramadan on stature during childhood and adolescence: Evidence from the Indonesian Family Life Survey.

Many pregnant Muslim women fast during the Muslim holy month of Ramadan. A number of studies have reported negative life outcomes in adulthood for children who were prenatally exposed to Ramadan. However, other studies document minimal to no impact on neonatal indicators. Using data from the Indonesian Family Life Survey consisting of 45,246 observations of 21,723 children born to 9771 mothers, we contribute to the current discussion on prenatal exposure to Ramadan by examining the effects on stature (height-for-age Z-scores, weight-for-age Z-scores, and body-mass-index-for-age Z-scores: HAZ, WAZ, and BAZ, respectively) from early childhood to late adolescence (0-19 years of age). We introduce an objective mother's religiosity indicator to improve the intention-to-treat estimations. Children were classified into three groups based on their mother's religion-religiosity: religious Muslims, less-religious Muslims, and non-Muslims. Using cluster-robust mother fixed-effects, we found negative effects on stature for children born to religious Muslim mothers. The effects were age-dependent and timing-sensitive. For example, children born to religious Muslim mothers were shorter in late adolescence (15-19 years of age) compared to their unexposed siblings if they were prenatally exposed in the first trimester of pregnancy (HAZ difference = -0.105 SD; p-val. <0.05). Interestingly, we found positive effects on stature for exposed less-religious Muslim children that peak in early adolescence (10-14 years of age) and negative effects on stature for exposed non-Muslim children that occur only in early childhood (0-4 years of age). We nuance our discussion of health and socioeconomic factors to explain these surprising results.

Parenthood and Well-Being: The Moderating Role of Leisure and Paid Work.

This study contributes to our knowledge on the association between parenthood and psychological well-being by examining whether pre-parenthood lifestyles (leisure and paid work) moderate the transition to parenthood. We expected that people with less active lifestyles would find it easier to adapt to the demands of parenthood. Using eleven waves of the Swiss Household Panel (N = 1332 men and 1272 women; 1999-2008, 2010), fixed effects models are estimated for men and women separately. Results show that-on average-parenthood was not associated with well-being for men, whereas it increased well-being for women. As expected, the well-being premium/cost to parenthood was contingent upon individuals' lifestyle before the transition to parenthood. For men, parenthood reduced well-being, but only if they frequently participated in leisure before the birth of the child. For women, motherhood had a beneficial effect on well-being but this effect was weaker for women who combined leisure with working long hours before motherhood.

Genome-wide analysis identifies 12 loci influencing human reproductive behavior.

The genetic architecture of human reproductive behavior-age at first birth (AFB) and number of children ever born (NEB)-has a strong relationship with fitness, human development, infertility and risk of neuropsychiatric disorders. However, very few genetic loci have been identified, and the underlying mechanisms of AFB and NEB are poorly understood. We report a large genome-wide association study of both sexes including 251,151 individuals for AFB and 343,072 individuals for NEB. We identified 12 independent loci that are significantly associated with AFB and/or NEB in a SNP-based genome-wide association study and 4 additional loci associated in a gene-based effort. These loci harbor genes that are likely to have a role, either directly or by affecting non-local gene expression, in human reproduction and infertility, thereby increasing understanding of these complex traits.

Representativeness of the LifeLines Cohort Study.

BACKGROUND: LifeLines is a large prospective population-based three generation cohort study in the north of the Netherlands. Different recruitment strategies were adopted: recruitment of an index population via general practitioners, subsequent inclusion of their family members, and online self-registration. Our aim was to investigate the representativeness of the adult study population at baseline and to evaluate differences in the study population according to recruitment strategy. METHODS: Demographic characteristics of the LifeLines study population, recruited between 2006-2013, were compared with the total adult population in the north of the Netherlands as registered in the Dutch population register. Socioeconomic characteristics, lifestyle, chronic diseases, and general health were further compared with participants of the Permanent Survey of Living Conditions within the region (2005-2011, N = 6,093). Differences according to recruitment strategy were assessed. RESULTS: Compared with the population of the north of the Netherlands, LifeLines participants were more often female, middle aged, married, living in a semi-urban place and Dutch native. Adjusted for differences in demographic composition, in LifeLines a smaller proportion had a low educational attainment (5% versus 14%) or had ever smoked (54% versus 66%). Differences in the prevalence of various chronic diseases and low general health scores were mostly smaller than 3%. The age profiles of the three recruitment groups differed due to age related inclusion criteria of the recruitment groups. Other differences according to recruitment strategy were small. CONCLUSIONS: Our results suggest that, adjusted for differences in demographic composition, the LifeLines adult study population is broadly representative for the adult population of the north of the Netherlands. The recruitment strategy had a minor effect on the level of representativeness. These findings indicate that the risk of selection bias is low and that risk estimates in LifeLines can be generalized to the general population.

Does education buffer the impact of disability on psychological distress?

This paper investigates whether education buffers the impact of physical disability on psychological distress. It further investigates what makes education helpful, by examining whether cognitive ability and occupational class can explain the buffering effect of education. Two waves of the 1958 British National Child Development Study are used to test the hypothesis that the onset of a physical disability in early adulthood (age 23 to 33) has a smaller effect on psychological distress among higher educated people. In total 423 respondents (4.6%) experienced the onset of a physical disability between the ages of 23 and 33. We find that a higher educational level cushions the psychology impact of disability. Cognitive ability and occupational class protect against the effect of a disability too. The education buffer arises in part because individuals with a higher level of education have more cognitive abilities, but the better social position of those with higher levels of education appears to be of greater importance. Implications of these findings for the social gradient in health are discussed.