The impact of poor health on academic performance: New evidence using genetic markers

Genetics, pharmacotherapy, and dietary interventions in childhood obesity

Childhood obesity has emerged as a major global health issue, contributing to the increased prevalence of chronic conditions and adversely affecting the quality of life and future prospects of affected individuals, thereby presenting a substantial societal challenge. This complex condition, influenced by the interplay of genetic predispositions and environmental factors, is characterized by excessive energy intake due to uncontrolled appetite regulation and a Westernized diet. Managing obesity in childhood requires specific considerations compared with adulthood, given the vulnerability of the critical juvenile-adolescent period to toxicity and developmental defects. Consequently, common treatment options for adult obesity may not directly apply to younger populations. Therefore, research on childhood obesity has focused on genetic defects in regulating energy intake, alongside pharmacotherapy and dietary interventions as management approaches, with an emphasis on safety concerns. This review aims to summarize canonical knowledge and recent findings on genetic factors contributing to childhood obesity. Additionally, it assesses the efficacy and safety of existing pharmacotherapies and dietary interventions and suggests future research directions. By providing a comprehensive understanding of the complex dynamics of childhood obesity, this review aims to offer insights into more targeted and effective strategies for addressing this condition, including personalized healthcare solutions.

Child health and its effect on adult social capital accumulation

Although studies have demonstrated important effects of poor health in childhood on stocks of human and health capital, little research has tested economic theories to investigate the effect of child health on social capital in adulthood. Studies on the influence of child health on adult social capital are mixed and have not used sibling fixed effects models to account for unmeasured family and genetic characteristics, that are likely to be important. Using the Add-Health sample, health in childhood was assessed as self-rated health, the occurrence of a physical health condition or mental health condition, while social capital in adulthood was measured as volunteering, religious service attendance, team sports participation, number of friends, social isolation, and social support. We used sibling fixed effects models, which attenuated several associations to non-significance. In sibling fixed effects models there was significant positive effects of greater self-rated health on participation in team sports and social support, and negative effect of mental health in childhood on social isolation in adulthood. These results suggest that children with poor health require additional supports to build and maintain their stock of social capital and highlight further potential benefits to efforts that address poor child health.

Early Weight Status and Human Capital in Adulthood: A 32-Year Follow-Up of the 1970 British Cohort Study

Objectives: To prospectively evaluate the effects of early weight status (childhood and adolescence) and changes in obesity status on human capital in adulthood. Methods: We employed data from the 1970 Birth Cohort Study in the United Kingdom. Data on height and weight during childhood and adolescence, human capital variables in adulthood were collected from 2,444 participants. Human capital includes cognitive ability, non-cognitive skill, educational attainment and health status. Data were analyzed through linear regression and logistic regression models. Results: Our results showed that obesity during adolescence was negatively associated with cognitive ability (β = -0.83, p < 0.01), educational attainment (β = -0.49, p < 0.01), and some health outcomes; and that underweight in childhood also adversely affected educational attainment in females (β = -0.66, p < 0.05). In terms of changes in obesity status, becoming obese in adolescence negatively affected cognitive ability (β = -1.18, p < 0.01), educational attainment (β = -0.62, p < 0.05) and some health outcomes, remaining obese was associated with all adverse health outcomes. Conclusion: Our results suggest that obesity during adolescence negatively affects a range of human capital outcomes in adulthood, and adolescence is a critical period during which early obesity affects adult human capital.

Do community-related traumatic events affect academic outcomes among adolescents? Quasi-experimental evidence from the Sewol disaster in South Korea

The sinking of the South Korean ferry Sewol in April 2014 claimed a total of 304 lives. Among the victims were 250 students from Dan-won High School in the city of Ansan and 11 of their teachers. For the residents of Ansan, the tragedy marked the beginning of widespread psychological distress and overwhelming grief. Exploiting the disaster's quasi-experimental nature, we employ a difference-in-differences (DID) strategy to measure its impact on the academic performance of Ansan's high school students in 5 major subjects. Using peers from Ansan's neighboring cities as the control group, our results reveal that the disaster impaired performances particularly in mathematics and natural science, a finding that is more pronounced for female students. Our results highlight that it is of uttermost importance to provide comprehensive psychological support and interventions to traumatized students but also to the communities they live in to minimize adverse effects on educational attainment.

Exploring Wellness Through Concept Analysis

Modern wellness is a concept that has been discussed in the literature since the 1960's. To better understand wellness complexities in a school setting, a concept analysis was conducted using a modified version of Walker and Avant's method incorporating the nursing paradigm in the implications. A literature review was conducted and except for background information, the publication dates were limited to 2017-2022. Key search terms included "wellness," "school wellness," "wellness concept." Additional literature reviews were conducted based on data related to the definitions, attributes, antecedents, and consequences of wellness that were collected from the reviewed studies. Defining attributes of wellness included healthy habits, conscientiousness, and optimum state of health. The antecedents, consequences, and empirical referents of wellness were identified with examples from the literature and case exemplars. Wellness is a dynamic process that has unique implications for school health and school nurses. This concept analysis lays the foundation for future research incorporating nursing domains.

A hard pill to swallow? Parental health shocks and children's mental health

Based on comprehensive administrative health record data from Austria, this study examines how children's mental health responds to a severe parental health shock. To account for the endogeneity of a serious parental illness, our sample is restricted to children who experience the health shock of a parent at some point in time and we exploit the timing of shocks in a dynamic DID setting. We find a positive causal effect of parental health shocks on children's mental health care utilization. Affected children have higher medical attendance for the treatment of mental illnesses, consume more psychotropic drugs, and are more likely to be hospitalized with mental and behavioral disorders. A significant increase in the utilization of antidepressants, anxiolytics, and sedatives can be observed for older children, girls and children with a white-collar family background. Our findings have important policy implications for children's access to psychotherapies and mental health care after experiencing a traumatic household event.

Factors affecting academic performance of college students in China during COVID-19 pandemic: a cross-sectional analysis

Introduction

Understanding the factors that affected academic performance of students during the COVID-19 pandemic will help design effective interventions for improving students' academic performance during emergency situations as well as during regular academic environment. This cross-sectional study aimed to identify the factors that explain academic performance of students in China during the pandemic.

Methods

Data on college students from the 2020 China Family Panel Studies were used, and the final sample consisted of 728 students. Ordered probit regression models were estimated to explain students' relative performance in the semester when the in-person classes were suspended by using various student and household-related variables and characteristics. To compute missing values in selected variables, a multiple imputation technique was applied.

Results

The odds of poor academic performance declined with higher Internet use for academic purposes, but Internet use for entertainment increased the probability of being in the poor academic performance. College students who spent more time studying on college work were less likely to have poor academic performance.

Discussion

This study identified the factors (Internet use and study time) associated with academic performance among Chinese college students during the COVID-19 pandemic. These results can be used to design policies to improve educational outcomes and to address educational inequalities.

Mental health, gender, and higher education attainment

We compared the mental health of higher education students with that of nonstudents. Moreover, we examined whether the mental health of students predicts their probability of obtaining a higher education degree, and whether the extent to which mental health affects educational attainment varies by gender. Drawing on a risk and resilience framework, we considered five facets of mental health that may be implicated in distinct ways in the educational attainment process: positive attitude towards life, self-esteem, self-efficacy, negative affectivity, and perceived stress. We used data from a nationally representative panel study from Switzerland (Nstudents = 2070, 42.8% male; Nnonstudents = 3755, 45.9% male). The findings suggest that overall, the mental health of higher education students was relatively similar to that of nonstudents, although students exhibited slightly higher self-esteem, slightly weaker self-efficacy, greater negative affectivity, and higher levels of perceived stress. The effects of different facets of mental health on higher education degree attainment were mostly statistically and/or practically insignificant. However, positive attitudes towards life had a substantial positive effect on the probability of being awarded a higher education degree. Mental health was equally important for male and female students' educational attainment.

Supplementary Information

The online version of this article (10.1007/s11618-023-01187-3) contains supplementary material, which is available to authorized users.

A national multiple baseline cohort study of mental health conditions in early adolescence and subsequent educational outcomes in New Zealand

Young people experiencing mental health conditions are vulnerable to poorer educational outcomes for many reasons, including: social exclusion, stigma, and limited in-school support. Using a near-complete New Zealand population administrative database, this prospective cohort study aimed to quantify differences in educational attainment (at ages 15-16 years) and school suspensions (over ages 13-16 years), between those with and without a prior mental health condition. The data included five student cohorts, each starting secondary school from 2013 to 2017 respectively (N = 272,901). Both internalising and externalising mental health conditions were examined. Overall, 6.8% had a mental health condition. Using adjusted modified Poisson regression analyses, those with prior mental health conditions exhibited lower rates of attainment (IRR 0.87, 95% CI 0.86-0.88) and higher rates of school suspensions (IRR 1.63, 95% CI 1.57-1.70) by age 15-16 years. Associations were stronger among those exhibiting behavioural conditions, compared to emotional conditions, in line with previous literature. These findings highlight the importance of support for young people experiencing mental health conditions at this crucial juncture in their educational pathway. While mental health conditions increase the likelihood of poorer educational outcomes, deleterious outcomes were not a necessary sequalae. In this study, most participants with mental health conditions had successful educational outcomes.

Boys with overweight status lagged behind girls with overweight status in reading: evidence from mendelian randomization

OBJECTIVES

We investigated the relationship between childhood weight status and academic achievement across sexes and different school subjects in Norway.

STUDY DESIGN AND SETTING

We used data from the Norwegian Mother, Father and Child Cohort Study (MoBa), which includes genetic data (N = 13,648, 8-year-old children). We employed within-family mendelian randomization, using a body mass index (BMI) polygenic risk score as an instrument to address unobserved heterogeneity.

RESULTS

Contrary to most previous findings, we observed that overweight status (including obesity) has more detrimental effects on reading achievement in boys than in girls; the test scores of boys with overweight were about a standard deviation lower than those of normal weight boys, and the negative effects on reading achievement became stronger in the later grade.

CONCLUSION

Previous obesity prevention studies have mainly targeted girls, based on the assumption that the obesity penalty is greater for girls. Our findings highlight that particular attention to boys with overweight may help reduce the existing gender gap in academic achievement.

Should I stay or should I go? The effect of London's terrorist attack on the educational choices of Muslims

This paper evaluates how the July 2005 London terrorist attacks affected Muslim teenagers' education plans and decisions. The attacks triggered a violent backslash against the Muslim community, which could have affected their incentives to continue in full-time education. I examine panel data on educational attitudes from the "Next Steps" Survey in England and use the month the survey was administered to divide individuals into treatment and control groups. I find that the attacks negatively affected the education plans of Muslims, but not those of any other major religious group. The probability of planning to continue in non-compulsory full-time education decreased by around 4.4% points for Muslims after the attacks. This corresponds to a 69% increase in individuals who were not sure whether to continue or drop out of full-time education. However, this change in plans appears to be a temporary reaction, since it did not affect students' actual decisions two years later.

Excess healthcare costs of psychological distress in young women: Evidence from linked national Medicare claims data

The prevalence of mental health disorders in young adults is increasing, yet there is limited empirical evidence on its economic consequences. We contribute to the literature by estimating the healthcare costs of psychological distress using panel data of young women (aged 18-23 years with a 5-year follow-up) from the Australian Longitudinal Study on Women's Health and linked administrative data from Medicare Australia. Our empirical strategy is based on the classical two-part model of healthcare costs with individual specific fixed-effects. We complement our analysis with a test for selection on unobservables to address potential concerns of endogeneity. We find that young women with psychological distress have 15% higher annual healthcare costs (excluding hospital costs) than women with no psychological distress. A large proportion of these costs is driven by the use of antidepressants and the services of psychiatrists and psychologists. We further find that women with psychological distress have higher out-of-pocket costs on these mental health related services compared to non-mental health specific services. Additionally, we show that the effect of psychological distress on healthcare costs is highest during the first 6 months of onset, which gradually decreases afterwards. The findings justify the importance of policy initiatives towards early prevention and treatment of psychological distress, especially among young women.

The impact of automatic enrolment on the mental health gap in pension participation: Evidence from the UK

A large body of evidence shows that individuals with poor mental health have lower income over the lifespan but a dearth of evidence exists on how poor mental health affects savings behaviour. In this paper, we provide novel evidence of a mental health gap in pension participation in the UK using nationally representative longitudinal data from Understanding Society (UKHLS). Beginning in 2012, the UK government introduced automatic enrolment enabling us to assess the impact of one of the largest pension policy reforms in the world on this mental health gap. We measure mental health using the General Health Questionnaire (GHQ-12) which is a commonly used tool for measuring psychological distress. Prior to automatic enrolment, we find that male private sector employees with poor mental health are 3.7 percentage points less likely to participate in a workplace pension scheme while female private sector employees with poor mental health are 2.9 percentage points less likely to participate after controlling for key observables including age, education, race, marital status, number of children, occupation type, industry type, presence of a physical health condition and cognitive ability. The implementation of automatic enrolment removes the mental health gap in pension participation, equalising the pension participation rates of individuals with and without poor mental health in the private sector.

Impact of Weight Status Reporting on Childhood Body Mass Index

Background: Many states have adopted school-based BMI screening or surveillance programs in an effort to address high rates of childhood obesity, some of which involve provision of confidential BMI reports to parents. While there is evidence that parents are attuned to information in the reports, there is less evidence showing that the reports are effective in preventing excess childhood weight gain. Methods: Data from Arkansas, the state with the nation's first and longest running and BMI screening program, were used to measure the impact of BMI reports. This was done through a regression discontinuity design that compared future BMI z-scores among children falling within a narrow band around the obese and overweight thresholds. We derived the effects of BMI reports by comparing students who received different types of reports around the relevant threshold. Results: While we are unable to detect any differences in BMI z-scores between the children who received the overweight report and the children who received the healthy weight report, we detected some differences between children who received the obese report and children who received the overweight report. These findings hold across subsamples by age, minority status, and school meal status. Conclusions: Based on these data, overweight or obese reports to do not meaningfully impact future BMI z-scores. This may be due, in part, to the format of parental reports, which may dampen the surprise element of an overweight or obese report.

Transdiagnostic internet-delivered therapy among post-secondary students: exploring student use and preferences for booster lessons post-treatment

Internet-delivered cognitive behaviour therapy (ICBT) is effective for treating anxiety and depression among post-secondary students, although outcomes are modest. Booster lessons have been proposed for maintaining and improving outcomes but have not been investigated following ICBT for students. This study used a mixed-methods approach to examine student (N = 146) use of a self-guided booster lesson offered 1 month after a 5-week ICBT course, whereby the booster lesson provided a review of ICBT skills and suggestions for maintaining motivation and problem solving. A survey about the booster was administered shortly after the booster to understand student preferences for the booster lessons, reasons for completing/not completing the booster, and satisfaction with the booster. Approximately one-third of students (n = 47) utilized the booster lesson. Completing a greater number of lessons during the main ICBT course was associated with uptake of the booster. The booster survey was completed by 20 of the 47 (∼43%) students who completed the booster lesson and 42 of the 99 who did not (∼42%). Students varied in perceptions of the ideal timing of the booster (1–2 weeks to 3–6 months) and approximately 60% expressed preference for completing the booster independently. Among non-completers of the booster, academic-related time constraints were the primary barrier to booster completion. Among those who completed the booster, the booster lesson was perceived as worthwhile, satisfaction was high, and the length was perceived as appropriate. Future research should examine if flexible delivery of booster lessons in terms of timelines and therapist support would increase booster uptake.

Key learning aims

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Health Economic Aspects of Childhood Excess Weight: A Structured Review

An economic perspective is crucial to understand the broad consequences of childhood excess weight (CEW). These can manifest in the form of elevated health care and societal costs, impaired health status, or inefficiencies in the allocation of resources targeted at its prevention, management, or treatment. Although existing systematic reviews provide summaries of distinct economic research strands covering CEW, they have a restricted focus that overlooks relevant evidence. The overarching aim of this structured review was to update and enhance recent key reviews of four strands of economic evidence in this area, namely, (1) economic costs associated with CEW, (2) health utilities associated with CEW, (3) economic evaluations of interventions targeting CEW, and (4) economic determinants and broader consequences of CEW. Our de novo searches identified six additional studies for the first research strand, five studies for the second, thirty-one for the third, and two for the fourth. Most studies were conducted in a small number of high-income countries. Our review highlights knowledge gaps across all the research strands. Evidence from this structured review can act as data input into future economic evaluations in this area and highlights areas where future economic research should be targeted.

Productivity, obesity, and human capital: Panel data evidence

The consequences of obesity for adults and children are well documented in the extant literature. We use panel data of 105 countries from 1990 to 2019 to estimate the effect of obesity on economic performance. We predict obesity using lagged values of child obesity as instruments. Predicted obesity has a negative and significant effect on productivity. This effect is independent of the effect of human capital and other macroeconomic determinants of economic performance. There is only weak evidence that this effect operates through the deterioration of human capital formation caused by childhood obesity.

Health endowments, schooling allocation in the family, and longevity: Evidence from US twins

We analyze data from the Minnesota Twin Registry (MTR), combined with the Socioeconomic Survey of Twins (SST), and new mortality data, and contribute to two bodies of literature. First, we demonstrate a beneficial causal effect of education on health and longevity in contrast to other twin-based studies of the US population, which show little or no effect of education on health. Second, we present evidence that is consistent with parental compensation through education for differences in their children's endowments that predict health, but find no evidence that parents reinforce differences in endowments that predict earnings. We argue that there is a bias towards detecting reinforcement both in this paper and in the literature. Despite this bias, we still find statistical evidence of compensating behavior. We account for observed and unobserved confounding factors, sample selection bias, and measurement error in education.

The effect of gender-specific labor market conditions on children's weight

BACKGROUND

Macroeconomic conditions are widely known to influence health outcomes through direct behavioral change or indirect mental effects of individuals. However, they have not received much attention in relation to childhood obesity.

METHODS

Using gender-specific predicted employment growth rates as an index for labor market conditions, we analyze how economic shocks affect children's weight status in Arkansas. To understand the underlying mechanisms behind these results, we use data on individual time use to examine how economic shocks are related to activities related to children's weight.

RESULTS

Improvement in the female labor market is associated with an increase in body mass index (BMI) and the probability that a child is overweight or obese, while an improvement in the male labor market has no significant effects on children's weight. This impact is particularly evident among female children, older children, and African-American children. We also find a negative effect of improvements in the female labor market on time spent on preparation for foods at home.

CONCLUSIONS

These results suggest that a decrease in time spent preparing home-cooked foods might be a plausible explanation for the pro-cyclical relationship between children's weight and improvement in the labor market conditions. Thus, the policy implications of our paper should be aimed at mitigating the adverse effects of women's labor participation.

Differences in Fitness and Academic Attainment between Obese, and Non Obese School-Age Adolescent Handball Players: An Explorative, Cross-Sectional Study

This study investigated differences in physical fitness and academic attainment in obese and non-obese adolescent handball players. A total of 31 males (age: 15.5 ± 1.2 years; body mass: 77.8 ± 17.7 kg; height: 1.71 ± 0.10 m; body mass index (BMI): 26.8 ± 6.9 kg/m2; body fat: 26.4 ± 6.34%) from the Qatar handball first division participated and were divided into two body fat percentage (%BF) groups (i.e., obese or non-obese). Anthropometrics (height, mass, BMI, and %BF) and physical performance testing ability (T-half test for change-of-direction (COD); squat jump (SJ), countermovement jump (CMJ), and 10 and 15 m sprints; medicine ball throw (MBT), and aerobic capacity (Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1)) were determined. Academic attainment was determined through grade point averages (GPA). Non-obese participants had superior performances in mathematics (p < 0.001) and science (p = 0.013), agility T-half test (p = 0.001), CMJ (p < 0.001), and 15 m sprint (p = 0.019). Correlations were found between T-half test and mathematics (r = 0.500) and science (r = 0.484). To conclude, obese school-age handball players have poorer fitness and academic performances than normal body weight adolescents.

The weight of school grades: Evidence of biased teachers' evaluations against overweight students in Germany

Discrimination and prejudice against overweight people is common in Western societies. In this article we aim to understand whether these attitudes reverberate into the school setting, by investigating whether teachers grade overweight students more severely than comparable normal weight students. By relying on the Attribution-Value Model of Prejudice (AVMP) and previous studies, we test a series of hypotheses using data from the German National Educational Panel Study (NEPS SC3) on a sample of students enrolled in the 7^th grade (lower secondary education). We used hierarchical ordered logit regression to assess whether overweight and obese students receive systematically lower grades by their teachers in German and mathematics, adjusting for subject-specific competences measured with a standardized test, and a rich set of socio-demographic and socio-psychological students’ characteristics (e.g. the “big five”). Results suggested that overweight and obese students were more severely graded in both subjects. The penalty for overweight students, and especially for obese students, was slightly larger in German and in the lowest part of the grade distribution. There was also indication of heterogeneous penalties by gender, with overweight male students being especially penalized in math. Possible ways to help teachers in assigning grades in a fairer way are discussed at the end.

Physical Fitness and Academic Performance in Normal Weight, Overweight, and Obese Schoolchild Handball Players in Qatar: A Pilot Study

This study aimed to investigate the relationships between physical fitness and academic performance in youth handball players of different BMI classifications. Thirty-three male handball players (age: 10.3 ± 0.61 years; body mass: 47.1 ± 12.1 kg; height: 1.43 ± 0.09 m; BMI: 23.1 ± 4.37 kg/m²; body fat: 20.6 ± 6.27%) were recruited from the Qatar handball first league and were assigned to their BMI age-adjusted groups (i.e., normal weight, overweight, and obese). Measurements included anthropometric data (height, mass, body mass index (BMI) and body fat percentage (%BF), and physical performance tests: agility T-half test; squat jump (SJ), and countermovement jump (CMJ), 10 and 15 m sprint; medicine ball throw (MBT). Aerobic capacity was evaluated using the Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1). Academic achievement was assessed through school records of grades point average (GPA) of Mathematics, Science and Arabic. None academic performance parameter and four physical performance parameters (agility T-half: p = 0.035; CMJ: p = 0.001; SJ: p = 0.007; sprint 10 m: p = 0.028) were different between BMI related groups. In 43% (3/7) of performance parameters and all academic parameters, the normal weight group showed the highest performance level, whereas the overweight group had the best performance in both sprint tests. The obese group was only superior in the medicine ball throw, but not at the p < 0.05 level. A relevant relationship (r > 0.5) between academic and physical performance parameters was only found between Yo-Yo IR 1 and science (r = 0.548). A relevant correlation were found between CMJ and BMI (r = −0.569). The agility T-half test was correlated with CMJ (r = −0.614) and 10 m sprint (r = 0.523). These findings suggest being overweight or obese are related to science academic performance among schoolchildren athletes in Qatar. Possibly, a normal BMI could positively influence academic performance. Physical education teachers, staff, and administrators should be cognizant that health promotion interventions improving composition may have the additional potential to improve dimensions of academic performance.

The impact of childhood obesity on human capital in high-income countries: A systematic review

Current evidence of the impact of childhood obesity on human capital development does not point in a consistent direction, and its interpretation is challenging. We carried out a systematic review of studies from high-income countries that used robust causal inference approaches to assess the impact of childhood overweight and obesity on outcomes typically linked to human capital development in economics. Global Health, Medline and EconLit were used to search for peer-reviewed papers. Three reviewers independently assessed study quality using the Newcastle-Ottawa Scale. Nineteen papers representing 22 studies met the inclusion criteria. Included studies were categorized based on three components of human capital: cognitive performance (n = 18), measured through test scores; educational attainment (n = 3), through grade progression and college completion; and labour market outcomes (n = 1), through wages. We find that childhood overweight and obesity hinder education outcomes, with effects mostly observed at older ages of exposure measurement (12+ years). Girls with overweight and obesity experienced larger negative effects and more often than boys. Future research should elucidate the pathways through which childhood obesity impacts human capital development, to support policies that may mitigate those impacts, thus averting social costs that are currently widespread, increasing and unaccounted for.

Association of Mental Disorder in Childhood and Adolescence With Subsequent Educational Achievement

IMPORTANCE

Onset of mental disorders during childhood or adolescence has been associated with underperformance in school and impairment in social and occupational life in adulthood, which has important implications for the affected individuals and society.

OBJECTIVE

To compare the educational achievements at the final examination of compulsory schooling in Denmark between individuals with and those without a mental disorder.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study was conducted in Denmark and obtained data from the Danish Civil Registration System and other nationwide registers. The 2 cohorts studied were (1) all children who were born in Denmark between January 1, 1988, and July 1, 1999, and were alive at age 17 years (n = 629 622) and (2) all children who took the final examination at the end of ninth grade in both Danish and mathematics subjects between January 1, 2002, and December 31, 2016 (n = 542 500). Data analysis was conducted from March 1, 2018, to March 1, 2019.

EXPOSURES

Clinical diagnosis by a psychiatrist of any mental disorder or 1 of 29 specific mental disorders before age 16 years.

MAIN OUTCOMES AND MEASURES

Taking the final examination at the end of ninth grade and mean examination grades standardized as z scores with differences measured in SDs (standardized mean grade difference).

RESULTS

Of the total study population (n = 629 622; 306 209 female and 323 413 male), 523 312 individuals (83%) took the final examination before 17 years of age and 38 001 (6%) had a mental disorder before that age. Among the 542 500 individuals (274 332 female and 268 168 male), the mean (SD) age was 16.1 (0.33) years for the females and 16.2 (0.34) years for the males. Among the 15 843 female and 22 158 male students with a mental disorder, a lower proportion took the final examination (0.52; 95% CI, 0.52-0.53) compared with individuals without a mental disorder (0.88; 95% CI, 0.88-0.88). Mental disorders affected the grades of male individuals (standardized mean grade difference, -0.30; 95% CI, -0.32 to -0.28) more than the grades of their female peers (standardized mean grade difference, -0.24; 95% CI, -0.25 to -0.22) when compared with same-sex individuals without mental disorders. Most specific mental disorders were associated with statistically significantly lower mean grades, with intellectual disability associated with the lowest grade in female and male students (standardized mean grade difference, -1.07 [95% CI, -1.23 to -0.91] and -1.03 [95% CI, -1.17 to -0.89]; P = .76 for sex differences in the mean grades). Female and male students with anorexia nervosa achieved statistically significantly higher grades on the final examination (standardized mean grade difference, 0.38 [95% CI, 0.32-0.44] and 0.31 [95% CI, 0.11-0.52]; P = .54 for sex differences in the mean grades) compared with their peers without this disorder. For those with anxiety, attachment, attention-deficit/hyperactivity, and other developmental disorders, female individuals attained relatively lower standardized mean grades compared with their male counterparts.

CONCLUSIONS AND RELEVANCE

Results of this study suggest that, in Denmark, almost all mental disorders in childhood or adolescence may be associated with a lower likelihood of taking the final examination at the end of ninth grade; those with specific disorders tended to achieve lower mean grades on the examination; and female, compared with male, individuals with certain mental disorders appeared to have relatively more impairment. These findings appear to emphasize the need to provide educational support to young people with mental disorders.

MOVE MORE, GAIN LESS: EFFECT OF A RECREATIONAL TRAIL SYSTEM ON CHILDHOOD BMI

We investigate the effect of residential proximity to recreational trails on childhood body mass index (BMI). We find that children living within 0.5 miles of recreational trails have BMI z-scores that are 0.0412 to 0.0507 standard deviations lower than those who do not live within 0.5 miles of trails. We also find that living nearby trails reduces the probability of becoming obese by 1.6 percentage points. The impact for BMI z-score is larger for children qualifying for free or reduced-price meals and for Hispanic children. These findings suggest that improving neighborhood amenities conducive to physical activity may help reduce disparities in childhood obesity. (JEL I10, R10).

Cumulative social disadvantage and risk of attention deficit hyperactivity disorder: Results from a nationwide cohort study

Socioeconomic factors correlate with mental health and affect individual life chances. However, the influence of specific and cumulative social disadvantages on children's mental health problems has received little attention. Previous studies have primarily used global measures of mental health problems or aggregated indicators of socioeconomic status. We contribute to this research by including multiple indicators of parental social disadvantage to study independent and accumulative effects. The study focuses on the Attention Deficit/Hyperactivity Disorder (ADHD), which is known to affect children's educational and socioeconomic trajectories. ADHD is one of the most common child mental health problems and although heredity has been estimated to 76 percent, research suggests that a large social component remains in the prevalence. We exploit comprehensive high-quality registry data for the entire population of children born 1990-1999 in Denmark (N = 632,725). The ADHD prevalence is 3.68 percent. Estimates from linear probability models show that parental unemployment, relative income poverty, and low educational attainment increase children's risk of ADHD with 2.1 (95% CI 1.8-2.3), 2.3 (95% CI 2.1-2.5), and 3.5 percentage points (95% CI 3.3-3.7), respectively. Children who live with all three disadvantages face an increased risk of 4.9 percentage points.

Application of Mendelian Randomization to Investigate the Association of Body Mass Index with Health Care Costs

Causal effect estimates for the association of obesity with health care costs can be biased by reversed causation and omitted variables. In this study, we use genetic variants as instrumental variables to overcome these limitations, a method that is often called Mendelian randomization (MR). We describe the assumptions, available methods, and potential pitfalls of using genetic information and how to address them. We estimate the effect of body mass index (BMI) on total health care costs using data from a German observational study and from published large-scale data. In a meta-analysis of several MR approaches, we find that models using genetic instruments identify additional annual costs of €280 for a 1-unit increase in BMI. This is more than 3 times higher than estimates from linear regression without instrumental variables (€75). We found little evidence of a nonlinear relationship between BMI and health care costs. Our results suggest that the use of genetic instruments can be a powerful tool for estimating causal effects in health economic evaluation that might be superior to other types of instruments where there is a strong association with a modifiable risk factor.

Mendelian Randomization analysis of the causal effect of adiposity on hospital costs

Estimates of the marginal effect of measures of adiposity such as body mass index (BMI) on healthcare costs are important for the formulation and evaluation of policies targeting adverse weight profiles. Most estimates of this association are affected by endogeneity bias. We use a novel identification strategy exploiting Mendelian Randomization - random germline genetic variation modelled using instrumental variables - to identify the causal effect of BMI on inpatient hospital costs. Using data on over 300,000 individuals, the effect size per person per marginal unit of BMI per year varied according to specification, including £21.22 (95% confidence interval (CI): £14.35-£28.07) for conventional inverse variance weighted models to £18.85 (95% CI: £9.05-£28.65) for penalized weighted median models. Effect sizes from Mendelian Randomization models were larger in most cases than non-instrumental variable multivariable adjusted estimates (£13.47, 95% CI: £12.51-£14.43). There was little evidence of non-linearity. Within-family estimates, intended to address dynastic biases, were imprecise.

Mendelian Randomization Analysis in Observational Epidemiology

Mendelian randomization (MR) in epidemiology is the use of genetic variants as instrumental variables (IVs) in non-experimental design to make causality of a modifiable exposure on an outcome or disease. It assesses the causal effect between risk factor and a clinical outcome. The main reason to approach MR is to avoid the problem of residual confounding. There is no association between the genotype of early pregnancy and the disease, and the genotype of an individual cannot be changed. For this reason, it results with randomly assigned case-control studies can be set by regressing the measurements. IVs in MR are used genetic variants for estimating the causality. Usually an outcome is a disease and an exposure is risk factor, intermediate phenotype which may be a biomarker. The choice of the genetic variable as IV (Z) is essential to a successful in MR analysis. MR is named 'Mendelian deconfounding' as it gives to estimate of the causality free from biases due to confounding (C). To estimate unbiased estimation of the causality of the exposure (X) on the clinically relevant outcome (Y), Z has the 3 core assumptions (A1-A3). A1) Z is independent of C; A2) Z is associated with X; and A3) Z is independent of Y given X and C; The purpose of this review provides an overview of the MR analysis and is to explain that using an IV is proposed as an alternative statistical method to estimate causal effect of exposure and outcome under controlling for a confounder.

Health endowment and later-life outcomes in the labour market: Evidence using genetic risk scores and reduced-form models

This paper examines the relationship between health endowment and later-life outcomes in the labour market. The analysis is based on reduced-form models in which labour market outcomes are regressed on genetic variants related to the increased risk of cardiovascular diseases. We use linked Finnish data that have many strengths. Genetic risk scores constitute exogenous measures for health endowment, and accurate administrative tax records on earnings, employment and social income transfers provide a comprehensive account of an individual's long-term performance in the labour market. The results show that although the direction of an effect is generally consistent with theoretical reasoning, the effects of health endowment on outcomes are statistically weak, and the hypothesis of no effect can be rejected only in one case: genetic endowment related to obesity influences male earnings and employment in prime age. Due to the sample size (N = 1651), the results should be interpreted with caution and should be confirmed in larger samples and in other institutional settings.

Health Related Quality of Life (HRQOL) and its correlation with academic performance of medical students

Objective:

To determine health related quality of life (HRQOL) of medical students and its correlation with their academic performance.

Methods:

Cross sectional study at Services Institute of Medical Sciences, included students of 4^th and final year MBBS, who filled SF-36 proforma of HRQOL. Scores of 8-domains and of physical component and mental component summary were determined. Marks in all professional examinations were used to stratify students as high performers (≥ 70% marks) and average performing students (< 70%). HRQOL scores was correlated with academic performance using unpaired student’s t-test.

Results:

Among 267 students included, mental health score (56.2±21.3) was lower than physical health component score (69.03±18.5). Role limitation due to emotional health (RE) (44.81), Vitality (VT) (54.19) and general health perception (GH) (58.89) had lower scores among 8-domains of questionnaire. Female students had significantly lower scores in role limitation due to emotional problems (p value <0.04), vitality (<0.05), bodily pain (p value <0.05) and general health perception (p value<0.03) than male students. Physical health and role limitation due to physical health domains were better in high performing students.

Conclusion:

Mental health of medical students is suboptimal, especially among female students. Students with better physical health have better academic performance.

The Relationship between Family Functioning and Academic Achievement in Female High School Students of Isfahan, Iran, in 2013-2014

Background:

Nowadays, the most important problem of the educational system is the vast spread of school failure. Therefore, detection of the factors leading to or preventing students' academic achievement is of utmost importance. Family function is considered to be a critical component of academic success. This study aimed to investigate the relationship between family functioning and academic achievement in high school female students in Isfahan.

Materials and Methods:

This descriptive correlational study was conducted through random sampling among 237 female high school students in Isfahan during school year 2013-2014. Data were collected by participants' personal characteristics and Bloom family function questionnaires. To analyze the data, descriptive statistics (mean and standard deviation) and inferential statistics (Pearson correlation and linear regression analysis) were adopted and computed using SPSS software.

Results:

The results showed a significant correlation between family function (except lack of independence) and students' academic achievement (p < 0.05). Further, among family function dimensions, expressiveness (β = 0.235, p < 0.001), family socialization (β = 0.219, p = 0.001), and cohesion (β = 0.211, p = 0.001) were more reliable predictors of academic achievement.

Conclusions:

The results of this study showed that students' academic achievement is highly correlated with the performance of their families. Therefore, to improve students' educational status in cultural and educational programs, which are specified for them, family function centered plans should be at the heart of attention.

For richer, for poorer: the relationship between adolescent obesity and future household economic prosperity

Adolescent obesity not only has serious long-term health implications, but also the potential to lead to a socioeconomic trajectory of lower earnings and household income. However, the magnitude and mechanisms of such outcomes across the life course are poorly understood. Using birth cohort data from the British National Child Development Study (1958 to 2008), we examined the relationship between adolescent obesity (at age 16) and future household income, employment, wages, marriage and spousal earnings when individuals were in their 30s, 40s and 50s. We additionally investigated the role of obesity persistence from childhood (age 11) through to adulthood (age 33). After adjusting for a rich set of childhood characteristics, compared to normal weight, obesity at age 16 was associated with significantly lower levels of future household income for women (by approximately 14%), but not men. This household income penalty was greater for women with obesity in both childhood and adulthood. The household income penalty for women appeared to be driven by a lower likelihood of marriage and lower spousal earnings for those who were married, and not by their own wage penalty in the labour market. The spousal earnings penalty occurred even when obesity did not persist into adulthood.

The Population Impact of Childhood Health Conditions on Dropout from Upper-Secondary Education

OBJECTIVES

To quantify how large a part of educational dropout is due to adverse childhood health conditions and to estimate the risk of dropout across various physical and mental health conditions.

STUDY DESIGN

A registry-based cohort study was conducted on a 20% random sample of Finns born in 1988-1995 (n = 101 284) followed for school dropout at ages 17 and 21. Four broad groups of health conditions (any, somatic, mental, and injury) and 25 specific health conditions were assessed from inpatient and outpatient care records at ages 10-16 years. We estimated the immediate and more persistent risks of dropout due to health conditions and calculated population-attributable fractions to quantify the population impact of childhood health on educational dropout, while accounting for a wide array of sociodemographic confounders and comorbidity.

RESULTS

Children with any health condition requiring inpatient or outpatient care at ages 10-16 years were more likely to be dropouts at ages 17 years (risk ratio 1.71, 95% CI 1.61-1.81) and 21 years (1.46, 1.37-1.54) following adjustment for individual and family sociodemographic factors. A total of 30% of school dropout was attributable to health conditions at age 17 years and 21% at age 21 years. Mental disorders alone had an attributable fraction of 11% at age 21 years, compared with 5% for both somatic conditions and injuries. Adjusting for the presence of mental disorders reduced the effects of somatic conditions.

CONCLUSIONS

More than one fifth of educational dropout is attributable to childhood health conditions. Early-onset mental disorders emerge as key targets in reducing dropout.

The effect of weight on mental health: New evidence using genetic IVs

Average body mass index (BMI) and depression prevalence grew over the last several decades, increasing medical expenditures. There is a strong correlation between obesity and depression but limited evidence on the causal effect of weight on mental health. I use an index of genetic risk for high BMI as a source of exogenous variation in weight to provide novel evidence on the effect of weight on mental health. This is one of the first studies to use genetics as an instrument for BMI and to examine the causal relationship between weight and depression. Results are mixed; I find a meaningful and significant effect of weight on suicidal ideation but no effects on counseling and an index of depression. The effect on suicidal ideation is concentrated in white females. From respondent and interviewer opinions of respondent attractiveness, social stigma is a mechanism through which weight affects mental health for white women.

THE DYNAMIC INTER-RELATIONSHIP BETWEEN OBESITY AND SCHOOL PERFORMANCE: NEW EMPIRICAL EVIDENCE FROM AUSTRALIA

This paper proposes a new empirical model for examining the relationship between obesity and school performance using the simultaneous equation modelling approach. The lagged effects of both learning and health outcomes were included to capture both the dynamic and inter-relational aspects of the relationship between obesity and school performance. The empirical application of this study used comprehensive data from the first five waves of the Longitudinal Study of Australian Children (LSAC), which commenced in 2004 (wave 1) and was repeated every two years until 2018. The study sample included 10,000 children, equally divided between two cohorts (infants and children) across Australia. The empirical results show that past learning and obesity status are strongly associated with most indicators of school outcomes, including reading, writing, spelling, grammar and numeracy national tests, and scores from the internationally standardized Peabody Picture Vocabulary Test and the Matrix Reasoning Test. The main findings of this study are robust due to the choice of obesity indicator and estimation methods.

High School Physical Education Requirements and Youth Body Weight: New Evidence from the YRBS

Previous research has found that high school physical education (PE) requirements are largely ineffective at reducing youth body weight. However, these studies were forced to rely on cross-state variation in PE requirements to identify their impacts, raising concerns that estimated policy effects may be confounded by state-level unobservables. Using data from the State and National Youth Risk Behavior Surveys and exploiting recent changes in state high school PE laws, we re-examine the effect of PE requirements on body weight. Our estimates show that a one-semester increase in PE requirements is associated with a 10 to 13% increase in minutes per week spent physically active in PE classes, but with no change in net vigorous exercise and little change in youth body weight. We conclude that substitution of in-school for outside-of-school physical activity and small resultant net energy expenditures can explain the absence of body weight effects. Copyright © 2016 John Wiley & Sons, Ltd.

Disentangling the Contemporaneous and Dynamic Effects of Human and Health Capital on Wages over the Life Cycle

We quantify the life-cycle effects of human and health capital on the wage distribution of women, with a focus on health capital measured by body mass. We use NLSY79 data on women followed annually up to twenty years during the time of their lives when average annual weight gain is greatest. We measure the wage impact of current body mass (i.e., the contemporaneous or direct effect) while controlling for observed measures of human capital (namely, educational attainment, employment experience, marital status tenure, and family size) and the impacts of an evolving body mass (i.e., the dynamic or indirect effects) on the endogenous histories of behaviors that produce these human capital stocks. We find significant differences in the contemporaneous and dynamic effects of body mass on wages by age, by race, and by wage level.

(How) Does Obesity Harm Academic Performance? Stratification at the Intersection of Race, Sex, and Body Size in Elementary and High School

In this study I hypothesize a larger penalty of obesity on teacher-assessed academic performance for white girls in English, where femininity is privileged, than in math, where stereotypical femininity is perceived to be a detriment. This pattern of associations would be expected if obesity largely influences academic performance through social pathways such as discrimination and stigma. In the Fragile Families and Child Wellbeing Study (~age 9) and the National Longitudinal Study of Youth 1997 (~age 18), I find obesity to be associated with a penalty on academic performance among white girls in English but not in math, while no association is found in either subject for white boys or for black students net of controls. Findings suggest that the relationship between obesity and academic performance may result largely from how educational institutions interact with bodies of different sizes, rather than primarily via constraints on physical health.

Height, body mass index, and socioeconomic status: mendelian randomisation study in UK Biobank

OBJECTIVE

To determine whether height and body mass index (BMI) have a causal role in five measures of socioeconomic status.

DESIGN

Mendelian randomisation study to test for causal effects of differences in stature and BMI on five measures of socioeconomic status. Mendelian randomisation exploits the fact that genotypes are randomly assigned at conception and thus not confounded by non-genetic factors.

SETTING

UK Biobank.

PARTICIPANTS

119,669 men and women of British ancestry, aged between 37 and 73 years.

MAIN OUTCOME MEASURES

Age completed full time education, degree level education, job class, annual household income, and Townsend deprivation index.

RESULTS

In the UK Biobank study, shorter stature and higher BMI were observationally associated with several measures of lower socioeconomic status. The associations between shorter stature and lower socioeconomic status tended to be stronger in men, and the associations between higher BMI and lower socioeconomic status tended to be stronger in women. For example, a 1 standard deviation (SD) higher BMI was associated with a £210 (€276; $300; 95% confidence interval £84 to £420; P=6 × 10(-3)) lower annual household income in men and a £1890 (£1680 to £2100; P=6 × 10(-15)) lower annual household income in women. Genetic analysis provided evidence that these associations were partly causal. A genetically determined 1 SD (6.3 cm) taller stature caused a 0.06 (0.02 to 0.09) year older age of completing full time education (P=0.01), a 1.12 (1.07 to 1.18) times higher odds of working in a skilled profession (P=6 × 10(-7)), and a £1130 (£680 to £1580) higher annual household income (P=4 × 10(-8)). Associations were stronger in men. A genetically determined 1 SD higher BMI (4.6 kg/m(2)) caused a £2940 (£1680 to £4200; P=1 × 10(-5)) lower annual household income and a 0.10 (0.04 to 0.16) SD (P=0.001) higher level of deprivation in women only.

CONCLUSIONS

These data support evidence that height and BMI play an important partial role in determining several aspects of a person's socioeconomic status, especially women's BMI for income and deprivation and men's height for education, income, and job class. These findings have important social and health implications, supporting evidence that overweight people, especially women, are at a disadvantage and that taller people, especially men, are at an advantage.

Education and Self-Reported Health: Evidence from 23 Countries on the Role of Years of Schooling, Cognitive Skills and Social Capital

We examine the contribution of human capital to health in 23 countries worldwide using the OECD Survey of Adult Skills, a unique large-scale international assessment of 16–65 year olds that contains information about self-reported health, schooling, cognitive skills and indicators of interpersonal trust, which represents the cognitive dimension of social capital. We identify cross-national differences in education, skill and social capital gradients in self-reported health and explore the interaction between human capital and social capital to examine if and where social capital is a mediator or a moderator of years of schooling and cognitive abilities. We find large education gaps in self-reported health across all countries in our sample and a strong positive relationship between self-reported health and both literacy and trust in the majority of countries. Education and skill gradients in self-reported health appear to be largest in the United States and smallest in Italy, France, Sweden and Finland. On average around 5.5% of both the schooling gap in self-reported health and the literacy gap in self-reported health can be explained by the higher levels of interpersonal trust that better educated/more skilled individuals have, although the mediating role of trust varies considerably across countries. We find no evidence of a moderation effect: the relationships between health and years of schooling and health and cognitive skills are similar among individuals with different levels of trust.

Genetic markers as instrumental variables

The use of genetic markers as instrumental variables (IV) is receiving increasing attention from economists, statisticians, epidemiologists and social scientists. Although IV is commonly used in economics, the appropriate conditions for the use of genetic variants as instruments have not been well defined. The increasing availability of biomedical data, however, makes understanding of these conditions crucial to the successful use of genotypes as instruments. We combine the econometric IV literature with that from genetic epidemiology, and discuss the biological conditions and IV assumptions within the statistical potential outcomes framework. We review this in the context of two illustrative applications.

Childhood Obesity and Cognitive Achievement

Obese children tend to perform worse academically than normal-weight children. If poor cognitive achievement is truly a consequence of childhood obesity, this relationship has significant policy implications. Therefore, an important question is to what extent can this correlation be explained by other factors that jointly determine obesity and cognitive achievement in childhood? To answer this question, we exploit a rich longitudinal dataset of Australian children, which is linked to national assessments in math and literacy. Using a range of estimators, we find that obesity and body mass index are negatively related to cognitive achievement for boys but not girls. This effect cannot be explained by sociodemographic factors, past cognitive achievement or unobserved time-invariant characteristics and is robust to different measures of adiposity. Given the enormous importance of early human capital development for future well-being and prosperity, this negative effect for boys is concerning and warrants further investigation.

The Relationship between Obesity and Cognitive Performance in Children: A Longitudinal Study

BACKGROUND

The relationship between obesity and academic outcomes remains unclear. We evaluated the association between obesity and cognitive performance in US children.

METHODS

We analyzed two nationally representative prospective cohorts of children in the 1979 National Longitudinal Survey of Youth, ages 2 through 8 at baseline and followed for 6 years, from 1988 to 1994 (cohort 1, n=2672) and 1994 to 2000 (cohort 2, n=1991). The main exposure variable was obesity (defined as never obese, became obese, always obese, and became nonobese). The main outcomes were standardized scores on four cognitive assessments. Univariate regression analyses of test scores on obesity were performed. Fixed-effects regression models, controlling for measured and unmeasured time-invariant confounders, were additionally adjusted for time-variant confounders to analyze the impact of change in obesity status on change in test scores.

RESULTS

Unadjusted analyses revealed a significant association between obesity and Peabody Individual Achievement Test (PIAT) scores. In cohort 1, always obese children had lower PIAT math scores than never obese children (β=-7.48; p<0.05). Always obese boys had lower PIAT math scores than those who were never obese (β=-16.45; p<0.01). In cohort 2, PIAT math scores were lower in the became obese category than the never obese category (β=-4.10; p<0.05). Always obese girls had lower PIAT reading scores than those who were never obese (β=-11.28; p<0.01). Fixed-effects models additionally adjusted for Home Observation Measurement of the Environment, Short Form score and height percentile showed no significant relationship between obesity and test scores in either cohort.

CONCLUSION

Childhood obesity is unlikely to be causally related to cognitive performance.

Mister Sandman, bring me good marks! On the relationship between sleep quality and academic achievement

There is growing evidence that health factors affect tertiary education success in a causal way. This study assesses the effect of sleep quality on academic achievement at university. To this end, we surveyed 804 students about their sleep quality by means of the Pittsburgh Sleep Quality Index (PSQI) before the start of their first exam period in December 2013 at Ghent University. PSQI scores were merged with course marks in this exam period. Instrumenting PSQI scores by sleep quality during secondary education, we find that increasing total sleep quality with one standard deviation leads to 4.85 percentage point higher course marks. Based on this finding, we suggest that higher education providers might be incentivised to invest part of their resources for social facilities in professional support for students with sleep and other health problems.

Cohort of birth modifies the association between FTO genotype and BMI

A substantial body of research has explored the relative roles of genetic and environmental factors on phenotype expression in humans. Recent research has also sought to identify gene-environment (or g-by-e) interactions, with mixed success. One potential reason for these mixed results may relate to the fact that genetic effects might be modified by changes in the environment over time. For example, the noted rise of obesity in the United States in the latter part of the 20th century might reflect an interaction between genetic variation and changing environmental conditions that together affect the penetrance of genetic influences. To evaluate this hypothesis, we use longitudinal data from the Framingham Heart Study collected over 30 y from a geographically relatively localized sample to test whether the well-documented association between the rs993609 variant of the FTO (fat mass and obesity associated) gene and body mass index (BMI) varies across birth cohorts, time period, and the lifecycle. Such cohort and period effects integrate many potential environmental factors, and this gene-by-environment analysis examines interactions with both time-varying contemporaneous and historical environmental influences. Using constrained linear age-period-cohort models that include family controls, we find that there is a robust relationship between birth cohort and the genotype-phenotype correlation between the FTO risk allele and BMI, with an observed inflection point for those born after 1942. These results suggest genetic influences on complex traits like obesity can vary over time, presumably because of global environmental changes that modify allelic penetrance.