Effect of weight on depression using multiple genetic instruments.

A striking global health development over the past few decades has been the increasing prevalence of overweight and obesity. At the same time, depression has become increasingly common in almost all high-income countries. We investigated whether body weight, measured by body mass index (BMI), has a causal effect on depression symptoms in Finland. Using data drawn from the Cardiovascular Risk in Young Finns Study (N = 1,523, mean age 41.9, SD 5), we used linear regression to establish the relationship between BMI and depression symptoms measured by 21-item Beck's Depression Inventory. To identify causal relationships, we used the Mendelian randomization (MR) method with weighted sums of genetic markers (single nucleotide polymorphisms, SNPs) as instruments for BMI. We employ instruments (polygenic risk scores, PGSs) with varying number of SNPs that are associated with BMI to evaluate the sensitivity of our results to instrument strength. Based on linear regressions, higher BMI was associated with a higher prevalence of depression symptoms among females (b = 0.238, p = 0.000) and males (b = 0.117, p = 0.019). However, the MR results imply that the positive link applies only to females (b = 0.302, p = 0.007) but not to males (b = -0.070, p = 0.520). Poor instrument strength may explain why many previous studies that have utilized genetic instruments have been unable to identify a statistically significant link between BMI and depression-related traits. Although the number of genetic markers in the instrument had only a minor effect on the point estimates, the standard errors were much smaller when more powerful instruments were employed.

The Individual-Level Productivity Costs of Physical Inactivity.

PURPOSE: This study estimated the long-term individual-level productivity costs of physical inactivity. METHODS: The data were drawn from the Northern Finland Birth Cohort 1966, to which the productivity cost variables (sick leaves and disability pensions) from Finnish registries were linked. Individuals ( N = 6261) were categorized into physical activity groups based on their level of physical activity, which was measured in three ways: 1) self-reported leisure-time moderate- to vigorous-intensity physical activity (MVPA) at 46 yr old, 2) longitudinal self-reported leisure-time MVPA at 31-46 yr old, and 3) accelerometer-measured overall MVPA at 46 yr old. The human capital approach was applied to calculate the observed costs (years 2012-2020) and the expected costs (years 2012-2031). RESULTS: The results showed that the average individual-level productivity costs were higher among physically inactive compared with the costs among physically active. The results were consistent regardless of the measurement type of physical activity or the period used. On average, the observed long-term productivity costs among physically inactive individuals were €1900 higher based on self-reported MVPA, €1800 higher based on longitudinal MVPA, and €4300 higher based on accelerometer-measured MVPA compared with the corresponding productivity costs among physically active individuals. The corresponding difference in the expected costs was €2800, €1200, and €8700, respectively. CONCLUSIONS: The results provide evidence that productivity costs differ according to an individual's level of physical activity. Therefore, investments in physical activity may decrease not only the direct healthcare costs but also the indirect productivity costs paid by the employee, the employer, and the government.

Schizophrenia polygenic risk score and long-term success in the labour market: A cohort study.

Employment is rare among people with a schizophrenia diagnosis. Meanwhile, a genetic liability for schizophrenia may hinder labour market performance. We studied how the polygenic risk score (PGS) for schizophrenia related to education and labour market outcomes. We found that a higher PGS was linked to lower educational levels and weaker labour market outcomes as well as a higher likelihood of receiving social income transfers, particularly among men. Assuming that the link is causal, our results indicate that individuals with schizophrenia or schizophrenia-related traits have a weakened ability to fully participate in the labour market, potentially reinforcing social exclusion.

Economic burden of low physical activity and high sedentary behaviour in Finland.

BACKGROUND: Low physical activity and high sedentary behaviour are unquestionably relevant for public health while also increasing direct and indirect costs. METHODS: The authors examined the direct and indirect costs attributable to low physical activity and high sedentary behaviour in Finland in 2017. Costs related to major non-communicable diseases drawn from Finnish registries covered direct costs (outpatient visits, days of inpatient care, medication and institutional eldercare) and indirect costs (sickness-related absences, disability pensions, unemployment benefits, all-cause mortality and losses of income tax revenue). Prevalences of low physical activity and high sedentary behaviour (≥8 hours per 16 waking hours) were based on self-reports among adolescents or accelerometer data among adults and the elderly from three Finnish population studies: FINFIT 2017, Health 2011 and the Cardiovascular Risk in Young Finns Study. Cost calculations used adjusted population attributable fractions (PAF) and regression models. Total annual costs were obtained by multiplying PAF by the total costs of the given disease. RESULTS: The total costs of low physical activity in Finland in 2017 came to approximately €3.2 billion, of which direct costs accounted for €683 million and indirect ones for €2.5 billion. Costs attributable to high sedentary behaviour totalled roughly €1.5 billion. CONCLUSION: The findings suggest that low physical activity and high sedentary behaviour levels create substantial societal costs. Therefore, actions intended to increase physical activity and reduce excessive sedentary behaviour throughout life may yield not only better health but also considerable savings to society.

Does better education mitigate risky health behavior? A mendelian randomization study.

Education and risky health behaviors are strongly negatively correlated. Education may affect health behaviors by enabling healthier choices through higher disposable income, increasing information about the harmful effects of risky health behaviors, or altering time preferences. Alternatively, the observed negative correlation may stem from reverse causality or unobserved confounders. Based on the data from the Cardiovascular Risk in Young Finns Study linked to register-based information on educational attainment and family background, this paper identifies the causal effect of education on risky health behaviors. To examine causal effects, we used a genetic score as an instrument for years of education. We found that individuals with higher education allocated more attention to healthy habits. In terms of health behaviors, highly educated people were less likely to smoke. Some model specifications also indicated that the highly educated consumed more fruit and vegetables, but the results were imprecise in this regard. No causal effect was found between education and abusive drinking. In brief, inference based on genetic instruments showed that higher education leads to better choices in some but not all dimensions of health behaviors.

Birth weight, adult weight, and cardiovascular biomarkers: Evidence from the Cardiovascular Young Finns Study.

This study quantifies the causal effect of birth weight on cardiovascular biomarkers in adulthood using the Cardiovascular Risk in Young Finns Study (YFS). We apply a multivariable Mendelian randomization (MVMR) method that provides a novel approach to improve inference in causal analysis based on a mediation framework. The results show that birth weight is linked to triglyceride levels (ß = -0.294; 95% CI [-0.591, 0.003]) but not to low-density lipoprotein (LDL) cholesterol levels (ß = 0.007; 95% CI [-0.168, 0.183]). The total effect of birth weight on triglyceride levels is partly offset by a mediation pathway linking birth weight to adult BMI (ß = 0.111; 95% CI [-0.013, 0.234]). The negative total effect is consistent with the fetal programming hypothesis. The positive indirect effect via adult BMI highlights the persistence of body weight throughout a person's life and the adverse effects of high BMI on health. The results are consistent with previous findings that both low birth weight and weight gain increase health risks in adulthood.

Birth weight and adult income: An examination of mediation through adult height and body mass.

This paper examines the causal links between early human endowments and socioeconomic outcomes in adulthood. We use a genotyped longitudinal survey (Cardiovascular Risk in Young Finns Study) that is linked to the administrative registers of Statistics Finland. We focus on the effect of birth weight on income via two anthropometric mediators: body mass index (BMI) and height in adulthood. We find that (i) the genetic instruments for birth weight, adult height, and adult BMI are statistically powerful; (ii) there is a robust total effect of birth weight on income for men but not for women; (iii) the total effect of birth weight on income for men is partly mediated via height but not via BMI; and (iv) the share of the total effect mediated via height is substantial, of approximately 56%.

Childhood physical activity as a labor market investment.

This study examined the role of physical activity and changes in physical activity levels during childhood in long-term labor market outcomes. To address this important but under-researched theme, the study utilized data drawn from longitudinal research, the Cardiovascular Risk in Young Finns Study (YFS), and from registries compiled by Statistics Finland. The study consisted of children aged 9 (n = 1565) and 15 (n = 2445) at the time their physical activity was measured. Labor market outcomes, including employment status, average employment months, and average unemployment months, were calculated from 1997 to 2010, when the participants were aged 20 to 48 years. Regression models were used to assess the relationship between physical activity and labor market outcomes. The results show that the consequences of childhood physical activity may be far-reaching, as higher childhood physical activity was positively related to the probability of being employed and employment months and was negatively related to unemployment months. On average, a one-unit increase in physical activity index was related to a 1% higher probability of being employed, 0.10 more months of yearly employment, and 0.05 fewer months of yearly unemployment. The results also imply that persistently active individuals had the highest level of employment and the lowest level of unemployment compared with other activity groups. In conclusion, investments in childhood physical activity may not only promote health and well-being but may also correlate with better labor market outcomes later in life, providing both personal and societal benefits.

Education leads to a more physically active lifestyle: Evidence based on Mendelian randomization.

Physical inactivity is a major health risk worldwide. Observational studies suggest that higher education is positively related to physical activity, but it is not clear whether this relationship constitutes a causal effect. Using participants (N = 1651) drawn from the Cardiovascular Risk in Young Finns Study linked to nationwide administrative data from Statistics Finland, this study examined whether educational attainment, measured by years of education, is related to adulthood physical activity in terms of overall physical activity, weekly hours of intensive activity, total steps per day, and aerobic steps per day. We employed ordinary least squares (OLS) models and extended the analysis using an instrumental variables approach (Mendelian randomization, MR) with a genetic risk score as an instrument for years of education. Based on the MR results, it was found that years of education is positively related to physical activity. On average, one additional year of education leads to a 0.62-unit higher overall physical activity (P < .01), 0.26 more hours of weekly intensive activity (P < .05), 560 more steps per day (P < .10), and 390 more aerobic steps per day (P < .09). The findings indicate that education may be a factor leading to higher leisure-time physical activity and thus promoting global health.

Longitudinal Associations between Physical Activity and Educational Outcomes.

PURPOSE: This longitudinal study examined the role of leisure-time physical activity in academic achievement at the end of compulsory basic education and educational attainment in adulthood. METHODS: The data were drawn from the ongoing longitudinal Cardiovascular Risk in Young Finns Study, which was combined with register-based data from Statistics Finland. The study consisted of children who were 12 yr (n = 1723, 49% boys) and 15 yr (n = 2445, 48% boys) of age at the time when physical activity was measured. The children were followed up until 2010, when their mean age was 40 yr. Physical activity was self-reported and included several measurements: overall leisure-time physical activity outside school hours, participation in sports club training sessions, and participation in sports competitions. Individuals' educational outcomes were measured with the self-reported grade point average at age 15 yr and register-based information on the years of completed postcompulsory education in adulthood. Ordinary least squares models and the instrumental variable approach were used to analyze the relationship between physical activity and educational outcomes. RESULTS: Physical activity in adolescence was positively associated with educational outcomes. Both the physical activity level at age 15 yr and an increase in the physical activity level between the ages of 12 and 15 yr were positively related to the grade point average at age 15 yr and the years of postcompulsory education in adulthood. The results were robust to the inclusion of several individual and family background factors, including health endowments, family income, and parents' education. CONCLUSION: The results provide evidence that physical activity in adolescence may not only predict academic success during compulsory basic education but also boost educational outcomes later in life.

Childhood Physical Activity and Adulthood Earnings.

PURPOSE: This study examined the associations between childhood physical activity level and adulthood earnings. METHODS: The data were drawn from the ongoing longitudinal Young Finns Study, which was combined with register-based Finnish Longitudinal Employer-Employee Data and register-based parents' background information from the Longitudinal Population Census of Statistics Finland. The study consisted of children who were 9 yr (n = 1257, 52% boys), 12 yr (n = 1662, 51% boys), and 15 yr (n = 1969, 49% boys) of age at the time when physical activity was measured. The children were followed until 2010, when they were between 33 and 45 yr old. Leisure-time physical activity in childhood was self-reported, whereas earnings in adulthood were register based and covered over a 10-yr period from 2000 to 2010. Ordinary least squares models were used to analyze the relationship between physical activity and earnings. RESULTS: Childhood physical activity level was positively associated with long-term earnings among men (P < 0.001). In more detail, a higher level of leisure-time physical activity at the age of 9, 12, and 15 yr was associated with an approximate 12%-25% increase in average annual earnings over a 10-yr period. The results were robust to controlling, e.g., an individual's chronic conditions and body fat, parents' education and physical activity, and family income. Among women, no relation was observed. CONCLUSIONS: The findings provide evidence that childhood physical activity can have far-reaching positive effects on adulthood earnings. Possibilities for improving physical activity during childhood may not only promote health but also affect long-term labor market outcomes.

Income and Physical Activity among Adults: Evidence from Self-Reported and Pedometer-Based Physical Activity Measurements.

This study examined the relationship between income and physical activity by using three measures to illustrate daily physical activity: the self-reported physical activity index for leisure-time physical activity, pedometer-based total steps for overall daily physical activity, and pedometer-based aerobic steps that reflect continuous steps for more than 10 min at a time. The study population consisted of 753 adults from Finland (mean age 41.7 years; 64% women) who participated in 2011 in the follow-up of the ongoing Young Finns study. Ordinary least squares models were used to evaluate the associations between income and physical activity. The consistency of the results was explored by using register-based income information from Statistics Finland, employing the instrumental variable approach, and dividing the pedometer-based physical activity according to weekdays and weekend days. The results indicated that higher income was associated with higher self-reported physical activity for both genders. The results were robust to the inclusion of the control variables and the use of register-based income information. However, the pedometer-based results were gender-specific and depended on the measurement day (weekday vs. weekend day). In more detail, the association was positive for women and negative or non-existing for men. According to the measurement day, among women, income was positively associated with aerobic steps despite the measurement day and with totals steps measured on the weekend. Among men, income was negatively associated with aerobic steps measured on weekdays. The results indicate that there is an association between income and physical activity, but the association is gender-specific and depends on the measurement type of physical activity.