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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 (β = -0.294; 95% CI [-0.591, 0.003]) but not to low-density lipoprotein (LDL) cholesterol levels (β = 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 (β = 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., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)

Using participants (N = 1733) drawn from the nationally representative longitudinal Young Finns Study (YFS) we estimate the effect of education on depressive symptoms. In 2007, when the participants were between 30 and 45 years old, they reported their depressive symptoms using a revised version of Beck's Depression Inventory. Education was measured using register information on the highest completed level of education in 2007, which was converted to years of education. To identify a causal relationship between education and depressive symptoms we use an instrumental variables approach (Mendelian randomization, MR) with a genetic risk score as an instrument for years of education. The genetic risk score was based on 74 genetic variants, which were associated with years of education in a genome-wide association study (GWAS). Because the genetic variants are randomly assigned at conception, they induce exogenous variation in years of education and thus identify a causal effect if the assumptions of the MR approach are met. In Ordinary Least Squares (OLS) estimation years of education in 2007 were negatively associated with depressive symptoms in 2007 (b = -0.027, 95% Confidence Interval (CI) = -0.040, -0.015). However, the results based on Mendelian randomization suggested that the effect is not causal (b = 0.017; 95% CI = -0.144, 0.178). This indicates that omitted variables correlated with education and depression may bias the linear regression coefficients and exogenous variation in education caused by differences in genetic make-up does not seem to protect against depressive symptoms., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objectives: The aim of this explorative study was to examine the effect of education on obesity using Mendelian randomization., Methods: Participants (N=2011) were from the on-going nationally representative Young Finns Study (YFS) that began in 1980 when six cohorts (aged 30, 33, 36, 39, 42 and 45 in 2007) were recruited. The average value of BMI (kg/m 2 ) measurements in 2007 and 2011 and genetic information were linked to comprehensive register-based information on the years of education in 2007. We first used a linear regression (Ordinary Least Squares, OLS) to estimate the relationship between education and BMI. To identify a causal relationship, we exploited Mendelian randomization and used a genetic score as an instrument for education. The genetic score was based on 74 genetic variants that genome-wide association studies (GWASs) have found to be associated with the years of education. Because the genotypes are randomly assigned at conception, the instrument causes exogenous variation in the years of education and thus enables identification of causal effects., Results: The years of education in 2007 were associated with lower BMI in 2007/2011 (regression coefficient (b)=-0.22; 95% Confidence Intervals [CI]=-0.29, -0.14) according to the linear regression results. The results based on Mendelian randomization suggests that there may be a negative causal effect of education on BMI (b=-0.84; 95% CI=-1.77, 0.09)., Conclusion: The findings indicate that education could be a protective factor against obesity in advanced countries., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objectives: To examine whether alcohol consumption in adulthood is related to the incidence of receiving a disability pension later in life., Methods: Twin data for Finnish men and women born before 1958 were matched to register-based individual information on disability pensions. Twin differences were used to eliminate both shared environmental and genetic factors. The quantity of alcohol consumption was measured as the weekly average consumption using self-reported data from three surveys (1975, 1981 and 1990). The disability pension data were evaluated from 1990-2004., Results: The models that account for shared environmental and genetic factors reveal that heavy drinkers are significantly more likely to receive a disability pension than moderate drinkers or constant abstainers. Heavy drinking that leads to passing out is also positively related to receiving a disability pension. The results were robust to the use of potential confounders that twins do not share, such as education years, the number of chronic diseases, physical activity at work and leisure, and stressful life events., Conclusion: Drinking profiles in early adulthood are an important predictor of receiving a disability pension later in life., (Copyright © 2015 Elsevier Inc. All rights reserved.)