Contribution of birth weight to mental health, cognitive and socioeconomic outcomes: two-sample Mendelian randomisation. (September 2021)

• Record Type: Journal Article
• Authors: Orri, Massimiliano; Pingault, Jean-Baptiste; Turecki, Gustavo; Nuyt, Anne-Monique; Tremblay, Richard E.; Côté, Sylvana M.; Geoffroy, Marie-Claude
• Is Part Of: British journal of psychiatry. Volume 219:Number 3(2021)
• Page Start: 507
• Page End: 514
• Publication Date: 2021-09
• Subjects: Psychiatric disorders -- birth weight -- Mendelian randomisation -- socioeconomic outcomes -- intelligence; Psychiatry -- Periodicals; Psychology, Pathological -- Periodicals; 616.89005
• DOI: 10.1192/bjp.2021.15
• Languages: English
• ISSNs: 0007-1250

Abstract

Abstract : Background: Low birth weight is associated with adult mental health, cognitive and socioeconomic problems. However, the causal nature of these associations remains difficult to establish owing to confounding. Aims: To estimate the contribution of birth weight to adult mental health, cognitive and socioeconomic outcomes using two-sample Mendelian randomisation, an instrumental variable approach strengthening causal inference. Method: We used 48 independent single-nucleotide polymorphisms as genetic instruments for birth weight (genome-wide association studies' total sample: n = 264 498) and considered mental health (attention-deficit hyperactivity disorder (ADHD), autism spectrum disorder, bipolar disorder, major depressive disorder, obsessive–compulsive disorder, post-traumatic stress disorder (PTSD), schizophrenia, suicide attempt), cognitive (intelligence) and socioeconomic (educational attainment, income, social deprivation) outcomes. Results: We found evidence for a contribution of birth weight to ADHD (OR for 1 s.d. unit decrease (~464 g) in birth weight, 1.29; 95% CI 1.03–1.62), PTSD (OR = 1.69; 95% CI 1.06–2.71) and suicide attempt (OR = 1.39; 95% CI 1.05–1.84), as well as for intelligence (β = −0.07; 95% CI −0.13 to −0.02) and socioeconomic outcomes, i.e. educational attainment (β = −0.05; 95% CI −0.09 to −0.01), income (β = −0.08; 95% CI −0.15 to −0.02) and social deprivation (β = 0.08; 95% CI 0.03–0.13). However, no evidence was found for a contribution of birth weight to the other examined mental health outcomes. Results were consistent across a wide range of sensitivity analyses. Conclusions: These findings support the hypothesis that birth weight could be an important element on the causal pathway to mental health, cognitive and socioeconomic outcomes.