No abstract

Growing evidence suggests that ADHD, an early onset neurodevelopmental disorder, is associated with poor somatic health in adulthood. However, the mechanisms underlying these associations are poorly understood. Here, we tested whether ADHD polygenic risk scores (PRS) are associated with mid-to-late life somatic health in a general population sample. Furthermore, we explored whether potential associations were moderated and mediated by life-course risk factors. We derived ADHD-PRS in 10,645 Swedish twins born between 1911 and 1958. Sixteen cardiometabolic, autoimmune/inflammatory, and neurological health conditions were evaluated using self-report (age range at measure 42–88 years) and clinical diagnoses defined by International Classification of Diseases codes in national registers. We estimated associations of ADHD-PRS with somatic outcomes using generalized estimating equations, and tested moderation and mediation of these associations by four life-course risk factors (education level, body mass index [BMI], tobacco use, alcohol misuse). Results showed that higher ADHD-PRS were associated with increased risk of seven somatic outcomes (heart failure, cerebro- and peripheral vascular disease, obesity, type 1 diabetes, rheumatoid arthritis, and migraine) with odds ratios ranging 1.07 to 1.20. We observed significant mediation effects by education, BMI, tobacco use, and alcohol misuse, primarily for associations of ADHD-PRS with cardiometabolic outcomes. No moderation effects survived multiple testing correction. Our findings suggests that higher ADHD genetic liability confers a modest risk increase for several somatic health problems in mid-to-late life, particularly in the cardiometabolic domain. These associations were observable in the general population, even in the absence of medical treatment for ADHD, and appear to be in part mediated by life-course risk factors.

Background and aims: Studies have indicated that maternal prenatal substance use may be associated with offspring attention deficit hyperactivity disorder (ADHD) via intrauterine effects. We measured associations between prenatal smoking, alcohol and caffeine consumption with childhood ADHD symptoms accounting for shared familial factors.Design: First, we used a negative control design comparing maternal and paternal substance use. Three models were used for negative control analyses: unadjusted (without confounders), adjusted (including confounders) and mutually adjusted (including confounders and partner's substance use). The results were meta-analysed across the cohorts. Secondly, we used polygenic risk scores (PRS) as proxies for exposures. Maternal PRS for smoking, alcohol and coffee consumption were regressed against ADHD symptoms. We triangulated the results across the two approaches to infer causality.

Background and aims: Several studies have indicated that maternal prenatal substance use may be associated with offspring ADHD via intrauterine effects. We investigated associations between maternal prenatal smoking, alcohol and caffeine consumption with childhood ADHD risk accounting for shared familial factors. Design: First, we used a negative control design comparing maternal and paternal substance use. Three models were used for negative control analyses: unadjusted (without confounders); adjusted (including confounders) and mutually adjusted (including confounders and partners substance use). The results were meta-analysed across the cohorts. Second, we used polygenic risk scores (PRS) as proxies for exposures. Maternal PRS for genetic variants of smoking, alcohol and coffee consumption were regressed against ADHD risk. We triangulated the results across the two approaches to infer causality. Setting: We used data from three longitudinal pregnancy cohorts: Avon Longitudinal Study of Parents and Children (ALSPAC) in the UK, Generation R study (GenR) in the Netherlands and Norwegian Mother, Father and Child Cohort study (MoBa) in Norway. Participants: Phenotype data available for children was: N(ALSPAC)=7,850; N(GENR)=3,849 and N(MOBA)=43,512. Genotype data available for mothers was: N(ALSPAC)=7,074 and N(MOBA)=14,583. Measurements: Offspring ADHD risk around age 7-8 was derived by dichotomising symptom scores from multiple questionnaires and parental self-reported substance use was measured at the 2nd pregnancy trimester. Findings: The pooled estimate for maternal prenatal substance use showed an association with ADHD risk (OR_SMOKING=1.11, 95%CI 1.00-1.23; OR_ALCOHOL=1.27, 95%CI 1.08-1.49; OR_CAFFEINE=1.05, 95%CI 1.00-1.11), while not for fathers (OR_SMOKING=1.03, 95%CI 0.95-1.13; OR_ALCOHOL=0.83, 95%CI 0.47-1.48; OR_CAFFEINE=1.02, 95%CI 0.97-1.07). However, maternal associations did not persist in sensitivity analyses (substance use before pregnancy, adjustment for maternal ADHD in MoBa). The PRS analyses did not show evidence of association in ALSPAC or MoBa. Conclusions: Our results do not provide support for a causal intrauterine effect of maternal prenatal substance use on offspring attention-deficit hyperactivity disorder risk.