Genetic mechanisms in the intergenerational transmission of health

What maternal educational mobility tells us about the mother's parenting routines, offspring school achievement and intelligence

BACKGROUND

Educational mobility at the macro-level is a common measure of social inequality. Nonetheless, the correlates of mobility of education at the individual level are less well studied. We evaluated whether educational mobility of the second generation (compared to the first generation level) predicts differences in parenting practices of the second generation and school achievement and intelligence in the third generation.

METHODS

Data from a population-based cohort of children in the Netherlands (N = 3547; 49.4% boys) were analyzed. Maternal, grandparental education and family routines, a parenting practice, were reported by the mother. Child school achievement at the end of primary school (∼12 years, with the national Dutch academic test score) and child intelligence (∼6 and 13 years) were measured in a standardized manner. Also, a child genome-wide polygenic score of academic attainment was calculated. To estimate the effect of educational mobility, inverse probability-weighted linear models and Diagonal Reference Models (DRM) were used.

RESULTS

Upward maternal educational mobility was associated with better offspring school achievement, higher intelligence, and more family routines if compared to offspring of mothers with no upward mobility. However, mothers did not implement the same level of family routines as similarly educated mothers and grandfathers who already had achieved this educational level. Likewise, children of mothers with upward educational mobility had lower school achievement and intelligence than children of similarly educated mothers with no mobility. Child's genetic potential for education followed a similar association pattern with higher potential in children of upward mobile mothers.

CONCLUSION

Policymakers might overlook social inequalities when focused on parental socioeconomic status. Grandparental socioeconomic status, which independently predicts child school achievement, intelligence, and parental family routines, should also be assessed. The child's genetic endowment reflects the propensity for education across generations that partly underlies mobility and some of its effect on the offspring.

Decoupling genetics from attainments: The role of social environments

This paper examines the extent to which growing up in a socially mobile environment might decouple genetic endowments related to educational attainment with actual attainments. Many models of intergenerational transmission of advantage contain both a transmission channel through endowments (i.e. genetics) from parents to children as well as from parental investments and "luck". Indeed, many scholars consider the intergenerational links due to the transmission of genetically-based advantage to place a lower bound on plausible levels of social mobility-genetics may be able to "lock in" advantage across generations. This paper explores this idea by using genetic measurements in the Health and Retirement Study to examine potential interactions between social environments and genetics related to attainments. The results suggest evidence of gene environment interactions: children born in high mobility states have lower genetic penetrance-the interaction between state-level mobility and the polygenic score for education is negative. These results suggest a need to incorporate gene-environment interactions in models of attainment and mobility and to pursue the mechanisms behind the interactions.

The intergenerational persistence of opioid dependence: Evidence from administrative data

To address the opioid crisis, it is crucial to understand its origins. We provide descriptive evidence for the intergenerational persistence of opioid dependence. Our analysis is based on administrative data covering the universe of Austrian births from 1984 to 1990. We consider prescription opioids and a new proxy for addiction to illicit opioids. We find that, if at least one parent is using illicit opioids, the likelihood of the child using increases from 1% to 7%. For prescription opioids, we observe an increase from 3.6% to 6.7%. Both associations are stable and do not change when controlling for environmental variables.

Intergenerational health effects of Medicaid

This paper investigates the effects of the introduction of Medicaid during the 1960s on next generations' birth outcomes. A federal mandate that all states must widen the coverage to all cash welfare recipients generated cross-state variations in Medicaid eligibility, specifically among nonwhites who largely overrepresented the target population. I implement a reduced-form difference-in-differences strategy that compares the birth outcomes of mothers born in states with higher cash welfare recipiency versus low welfare recipiency and different years relative to the Medicaid implementation year. Using Natality data (1970-2004), I find that Medicaid significantly improves birth outcomes. The effects are considerably larger among nonwhites, specifically blacks. The effects do not appear to be driven by preexisting trends in birth outcomes, preexisting trends in households' socioeconomic characteristics, changes in other welfare expenditures, and selective fertility. A back-of-an-envelope calculation points to a minimum of 3.9% social externality of Medicaid through income rises due to next generations' improvements in birth outcomes.

When in America, do as the Americans? The evolution of health behaviors and outcomes across immigrant cohorts

This study seeks to understand US immigrants' health-related behaviors and outcomes across arrival cohorts. We simultaneously examine risky consumption choices (smoking and drinking) and physical health conditions (asthma, diabetes, vision problems, and coronary heart diseases) using data from the National Health Interview Surveys (1989-2018). We incorporate cohort fixed-effects and the interactions between cohort effects and years since immigration into our empirical framework to capture the dynamics of immigrant health over time. For all health indicators, we find that there are important differences between arriving immigrants and natives. Despite some heterogeneity in the dynamics of unhealthy behaviors, this heterogeneity seems to dissipate as we explore longer-term health outcomes. Overall, our findings provide an interesting outlook on how the integration into the host society affects American immigrants' health. We contribute new results to the immigrant assimilation literature, which has primarily focused on obesity and wages.

Influence of parental physical activity on offspring's nutritional status: an intergenerational study in the 1993 Pelotas birth cohort

OBJECTIVE

To investigate the influence of parental physical activity on offspring's nutritional status in the 1993 Pelotas (Brazil) birth cohort.

DESIGN

Birth cohort study.

SETTING

The main outcomes were overweight and obesity status of children. The main exposure was parental physical activity over time, measured during the 11, 15 and 18 years of age follow-ups. The exposure was operationalised as cumulative, and the most recent measure before the birth of child. We adjusted Poisson regression models with robust variance to evaluate crude and adjusted associations between parental physical activity and offspring's nutritional status. All analyses were stratified according to the sex of the parent.

PARTICIPANTS

A total of 874 members from the 1993 Pelotas (Brazil) birth cohort followed-up at 22 years of age with their first-born child were analysed.

RESULTS

Children were, on average, 3·1 years old. Crude analyses showed that the mother's cumulative physical activity measure had an indirect association with the prevalence of children's obesity. The most recent maternal physical activity measure before the birth of the child was associated with 41 % lower prevalence of obesity in children, even after adjustment for confounders.

CONCLUSIONS

The most recent maternal physical activity measure was indirectly associated with the prevalence of obesity in children. No associations were found for fathers, reinforcing the hypothesis of a biological effect of maternal physical activity on offspring's nutritional status.

Nationwide evidence that education disrupts the intergenerational transmission of disadvantage

We leveraged a three-generation approach in 2.1 million Danes to measure the transmission and disruption of multiple health and social disadvantages: poor physical health, poor mental health, social welfare dependency, criminal offending, and protective services involvement. Health and social disadvantages clustered within a small segment of families: Adults who relied disproportionately on multiple, different health and social services tended to have parents who relied disproportionately on multiple, different health and social services and tended to have children who appeared in protective services records. Education disrupted these statistical associations between and within generations and between and within families. If associations are causal, investing in young people’s education potential could interrupt the multigenerational cycle of disadvantage and reduce health and social inequalities.

Despite overall improvements in health and living standards in the Western world, health and social disadvantages persist across generations. Using nationwide administrative databases linked for 2.1 million Danish citizens, we leveraged a three-generation approach to test whether multiple, different health and social disadvantages—poor physical health, poor mental health, social welfare dependency, criminal offending, and Child Protective Services involvement—were transmitted within families and whether education disrupted these statistical associations. Health and social disadvantages concentrated, aggregated, and accumulated within a small, high-need segment of families: Adults who relied disproportionately on multiple, different health and social services tended to have parents who relied disproportionately on multiple, different health and social services and tended to have children who evidenced risk for disadvantage at an early age, through appearance in protective services records. Intra- and intergenerational comparisons were consistent with the possibility that education disrupted this transmission. Within families, siblings who obtained more education were at a reduced risk for later-life disadvantage compared with their cosiblings who obtained less education, despite shared family background. Supporting the education potential of the most vulnerable citizens might mitigate the multigenerational transmission of multiple disadvantages and reduce health and social disparities.

Intergenerational health mobility: Magnitudes and Importance of Schools and Place

This paper broadens the literature on intergenerational persistence of socioeconomic status to consider individual, family, and spatial variation in intergenerational health mobility in the United States. Using a school-based representative panel (Add Health), we report overall health persistence of 0.17 with higher mobility in Hispanic families. We find large variation by place; intergenerational health persistence estimates range between 0 and 0.5, with similarly large ranges for absolute upward and downward health mobility. School- and contextual-level correlates indicate local race/ethnicity composition, proportion of single parents, and average mother's education may be related to observed variation in intergenerational health mobility.

Like Parent, Like Child: Intergenerational Patterns of Cardiovascular Risk Factors at Midlife

PURPOSE

We aimed to assess the prevalence of four cardiovascular risk factors (obesity, diabetes, excessive alcohol intake, and cigarette smoking) for parents and their adult children at the same approximate midlife age. We also evaluated associations of parents' cardiovascular risk factors, childhood health exposures, and social contexts (i.e., family, school, and neighborhood) during adolescence with adult children's cardiovascular health at midlife.

METHODS

We used data from respondents at Wave V of the National Longitudinal Study of Adolescent to Adult Health who had corresponding parent (mostly mothers) data from Wave I. The final sample included 10,466 adult children with a mean age of 37.8 years. Descriptive statistics and logistic regression models were estimated, accounting for the National Longitudinal Study of Adolescent to Adult Health sampling design.

RESULTS

At similar ages (i.e., 35-45 years) to their parents, adult children had higher rates of excessive drinking and obesity than their parents, lower rates of diabetes, and similar rates of smoking. Adult children's health largely converged and correlated with their parents' health at similar ages. Cardiovascular risks for adult children were also significantly associated with their childhood health exposures and social contexts during adolescence. Some associations varied with respect to the health status of parents at Wave I.

CONCLUSIONS

The cardiovascular risk of parents at midlife is strongly associated with the cardiovascular risk of their adult children at midlife. The status of parents' health during adolescence can also modify the significance and magnitude of associations between childhood health exposures or adolescent social contexts and adult children's cardiovascular risk factors.

Can shorter mothers have taller children? Nutritional mobility, health equity and the intergenerational transmission of relative height

This study develops the concept of nutritional mobility, defined here as the probability that a mother ranked low in her cohort's height distribution will have a child who attains a higher rank order. We demonstrate that rank-order regression provides a robust metric of health equity, revealing differences in opportunities for each child to reach their own growth potential. We estimate four indicators of nutritional mobility and test for associations between nutritional mobility and various local economic and environmental factors. Nutritional mobility has improved over time, and the nutrition environment contributes about 2.86 times as much as a mother's height to her child's expected rank in height-for-age. Populations with the least mobility are in Latin America, and the most mobility is in more urbanized areas of Africa and Asia. Rank-order mobility is an important aspect of health equity, offering valuable insight into the role of socioecological factors in nutrition improvement across generations.

Intergenerational transmission: Theoretical and methodological issues and an introduction to four Dutch cohorts

Behaviors, traits and characteristics are transmitted from parents to offspring because of complex genetic and non-genetic processes. We review genetic and non-genetic mechanisms of intergenerational transmission of psychopathology and parenting and focus on recent methodological advances in disentangling genetic and non-genetic factors. In light of this review, we propose that future studies on intergenerational transmission should aim to disentangle genetic and non-genetic transmission, take a long-term longitudinal perspective, and focus on paternal and maternal intergenerational transmission. We present four large longitudinal cohort studies within the Consortium on Individual Development, which together address many of these methodological challenges. These four cohort studies aim to examine the extent to which genetic and non-genetic transmission from the parental generation shapes parenting behavior and psychopathology in the next generation, as well as the extent to which self-regulation and social competence mediate this transmission. Conjointly, these four cohorts provide a comprehensive approach to the study of intergenerational transmission.

Inequality of opportunities in health and death: an investigation from birth to middle age in Great Britain

Objective

We assess the existence of unfair inequalities in health and death using the normative framework of inequality of opportunities, from birth to middle age in Great Britain.

Methods

We use data from the 1958 National Child Development Study, which provides a unique opportunity to observe individual health from birth to the age of 54, including the occurrence of mortality. We measure health status combining self-assessed health and mortality. We compare and statistically test the differences between the cumulative distribution functions of health status at each age according to one childhood circumstance beyond people’s control: the father’s occupation.

Results

At all ages, individuals born to a ‘professional’, ‘senior manager or technician’ father report a better health status and have a lower mortality rate than individuals born to ‘skilled’, ‘partly skilled’ or ‘unskilled’ manual workers and individuals without a father at birth. The gap in the probability to report good health between individuals born into high social backgrounds compared with low, increases from 12 percentage points at age 23 to 26 at age 54. Health gaps are even more marked in health states at the bottom of the health distribution when mortality is combined with self-assessed health.

Conclusions

There is increasing inequality of opportunities in health over the lifespan in Great Britain. The tag of social background intensifies as individuals get older. Finally, there is added analytical value to combining mortality with self-assessed health when measuring health inequalities.

Childhood Origins Of Intergenerational Health Mobility In The United States

Policy makers and parents should share a goal that all children have opportunities to thrive, regardless of their circumstances at birth. Studies that focus on socioeconomic measures of opportunities for thriving measure intergenerational mobility, or the extent to which children's outcomes can diverge from those of their parents. We bring this focus to the study of children's health by estimating intergenerational health mobility during early childhood in a national sample. We find that children in families characterized as minorities, those without health insurance, or those with low socioeconomic status experience less upward health mobility and greater downward health mobility. We also show that community characteristics may shape health mobility. For example, children growing up in places with high proportions of uninsured residents are less likely to experience upward health mobility and more likely to experience downward health mobility. These descriptive findings may allow new insights into ways in which children's health can be decoupled from their circumstances at birth.

Work-Limiting Disability and Intergenerational Economic Mobility

OBJECTIVE

To examine whether work-limiting disability may modify intergenerational economic mobility in the United States.

METHODS

Using the Panel Study of Income Dynamics, common metrics of intergenerational mobility are estimated by parent work-limiting disability. These include rank slope coefficients capturing persistence of socioeconomic status and absolute upward economic mobility capturing expected child outcomes.

RESULTS

Parent-child pairs with work-limiting disability experience five to twelve percentiles lower absolute economic mobility at the 25th percentile of parent income. More severe and/or chronic conditions have larger disparities and higher parent income is associated with smaller disparities. Women may experience larger mobility differences, while non-Hispanic black children may face a higher likelihood of parents experiencing work limitations.

CONCLUSIONS

Work-limiting disability appears to modify children's economic opportunity. This contributes to the understanding of disparate access to opportunity in the United States while also identifying economic disadvantages associated with disability for subsequent generations.

Parental education and adolescent health problems due to violence, self-harm and substance use: what is the role of parental health problems?

BACKGROUND

Adolescent health problems are more prevalent in families with low socioeconomic position, but few studies have assessed the role of parental health in this association. This study examines the extent to which parental health problems, particularly those related to high-risk health behaviour, might explain the association between parental education and adolescent health problems due to violence, self-harm and substance use.

METHODS

We used longitudinal register data on a 20% representative sample of all families with children aged 0-14 years in 2000 in Finland with information on parental social background and parental and offspring health problems based on hospital discharge data. We estimated discrete-time survival models with the Karlson-Holm-Breen method on hospital admissions due to violence, self-harm and substance use among adolescents aged 13-19 years in 2001-2011 (n=145 404).

RESULTS

Hospital admissions were 2-3 times more common among offspring of basic educated parents than tertiary educated parents. Similar excess risks were observed among those with parental mental health problems and parental health problems due to violence, self-harm and substance use. The OR for offspring of basic educated parents was attenuated from OR 2.73 (95% CI 2.34 to 3.18) to OR 2.38 (2.04 to2.77) with adjustment for parental health problems, particularly those due to violence, self-harm and substance use. Having both low parental education and parental health problems showed simple cumulative effects.

CONCLUSIONS

The excess risks of hospital admissions due to violence, self-harm and substance use among adolescents with lower educated parents are largely independent of severe parental health problems.

Influence of maternal height on children's health status and mortality: A cross-sectional study in poor Roma communities in rural Serbia

To determine possible variations in children's health status and mortality associated with variations in maternal stature, an anthropometric and demographic study was conducted in a Roma population of poor socio-economic status in rural Serbia. Data were collected during several years of anthropological fieldwork. The sample consisted of 691 women, ranging from 16 to 80 years of age. In addition to stature, Roma women's demographics, reproductive history, reproductive outcomes and health status of their children were collected. The results provide evidence of a significant association between mother's stature and their children's health and mortality, with a shorter mother's stature predisposing children to poor health and survival outcomes. The findings could prompt development of a definition of short stature among Roma women to evaluate the risk based on height distribution among the general Roma population.

Adolescence and the next generation

Adolescent growth and social development shape the early development of offspring from preconception through to the post-partum period through distinct processes in males and females. At a time of great change in the forces shaping adolescence, including the timing of parenthood, investments in today's adolescents, the largest cohort in human history, will yield great dividends for future generations.

Gene-Environment Interaction in the Intergenerational Transmission of Asthma

Researchers have found strong linkages between parent and child health, but the mechanisms underlying intergenerational health transmission are not well understood. This paper investigates how the importance of genetic health transmission mechanisms varies by environmental conditions in the case of pediatric asthma, the single most common chronic health condition among American children. Using a sample that includes approximately 2000 adoptees and a large number of similar biological families, I find that the relative importance of genetic transmission differs strongly by socioeconomic status (SES). In high SES families, parent-child asthma associations are approximately 75% weaker among adoptees than biological children, suggesting a dominant role for genetic transmission. In lower SES families, parent-child asthma associations are virtually identical across biological and adoptive children, suggesting a negligible role for genetic transmission. A potential interpretation of this difference is that as environmental conditions affecting asthma improve among higher SES children, an increasingly large share of asthma variation is due to genetics. Copyright © 2016 John Wiley & Sons, Ltd.

Exploring the intergenerational persistence of health behaviour: an empirical study of smoking from China

Background

It is of significance to look into the intergenerational transmission of risk behaviour to explain the disparity of health. Our paper contributes to the literature by providing evidence in the context of China, focusing on smoking behaviour.

Methods

This paper studies the intergenerational transmission of smoking in the context of China using a nationally representative dataset – the China Health and Nutrition Survey (CHNS). The two-part model, the Tobit model, and the fixed effects model are utilized for the empirical analysis, respectively.

Results

We found a strong intergenerational persistence of health behaviour. That is, parents’ smoking behaviour is positively correlated with their children’s smoking initiation.

Conclusions

Our study provides evidence of the intergenerational persistence of health behaviour in the case of smoking, in the world’s most populous country. This has policy implications for the issue of intergenerational mobility and health education, as well as for tobacco control in China.

Population health in an era of rising income inequality: USA, 1980-2015

Income inequality in the USA has increased over the past four decades. Socioeconomic gaps in survival have also increased. Life expectancy has risen among middle-income and high-income Americans whereas it has stagnated among poor Americans and even declined in some demographic groups. Although the increase in income inequality since 1980 has been driven largely by soaring top incomes, the widening of survival inequalities has occurred lower in the distribution-ie, between the poor and upper-middle class. Growing survival gaps across income percentiles since 2001 reflect falling real incomes among poor Americans as well as an increasingly strong association between low income and poor health. Changes in individual risk factors such as smoking, obesity, and substance abuse play a part but do not fully explain the steeper gradient. Distal factors correlated with rising inequality including unequal access to technological innovations, increased geographical segregation by income, reduced economic mobility, mass incarceration, and increased exposure to the costs of medical care might have reduced access to salutary determinants of health among low-income Americans. Having missed out on decades of income growth and longevity gains, low-income Americans are increasingly left behind. Without interventions to decouple income and health, or to reduce inequalities in income, we might see the emergence of a 21st century health-poverty trap and the further widening and hardening of socioeconomic inequalities in health.

Genes and the intergenerational transmission of BMI and obesity

This paper compares the strength of intergenerational transmission of body mass index (BMI) and obesity in a sample of adoptees relative to a matched sample of biological children with similar observable characteristics. We find that BMI and obesity are strongly correlated among biological parent-child pairs, but there are no significant intergenerational associations in these health traits among adoptive parent-child pairs. The intergenerational elasticity of BMI for children to their parents is 0.2 in the matched biological sample, but indistinguishable from zero for adopted children with a standard error more than three times as large as the coefficient. Under reasonable assumptions, these findings indicate that the intergenerational transmission of BMI and obesity occurs primarily through genetic mechanisms. Additional analyses of transmission rates by parental gender and among step-parents and step-children support this conclusion. The role of determinants of BMI and obesity in the household environment in relation to our findings is discussed. Given the negative consequences of obesity on earnings and other economic measures, our results suggest that the genetic transmission of weight problems contributes substantially to intergenerational persistence in economic outcomes.

The Effects of Parental Health Shocks on Adult Offspring Smoking Behavior and Self-Assessed Health

An important avenue for smoking deterrence may be through familial ties if adult smokers respond to parental health shocks. In this paper, we merge the Original Cohort and the Offspring Cohort of the Framingham Heart Study to study how adult offspring smoking behavior and subjective health assessments vary with elder parent smoking behavior and health outcomes. These data allow us to model the smoking behavior of adult offspring over a 30-year period contemporaneously with parental behaviors and outcomes. We find strong 'like father, like son' and 'like mother, like daughter' correlations in smoking behavior. We find that adult offspring significantly curtail their own smoking following an own health shock; however, we find limited evidence that offspring smoking behavior is sensitive to parent health, with the notable exception that women significantly reduce both their smoking participation and intensity following a smoking-related cardiovascular event of a parent. We also model the subjective health assessment of adult offspring as a function of parent health, and we find that women report significantly worse health following the smoking-related death of a parent. Copyright © 2015 John Wiley & Sons, Ltd.

Breaking the Intergenerational Cycle of Disadvantage: The Three Generation Approach

Health disparities in the United States related to socioeconomic status are persistent and pervasive. This review highlights how social disadvantage, particularly low socioeconomic status and the health burden it brings, is passed from 1 generation to the next. First, we review current frameworks for understanding the intergenerational transmission of health disparities and provide 4 illustrative examples relevant to child health, development, and well-being. Second, the leading strategy to break the cycle of poverty in young families in the United States, the 2-generation approach, is reviewed. Finally, we propose a new 3-generation approach that must combine with the 2-generation approach to interrupt the intergenerational cycle of disadvantage and eliminate health disparities.