Obesity and atypical depression symptoms: findings from Mendelian randomization in two European cohorts

Abstract

Studies considering the causal role of body mass index (BMI) for the predisposition (倾向；素质；易染病体质) of major depressive disorder (MDD) based on a Mendelian Randomization (MR) approach have shown contradictory (矛盾的) results. These inconsistent findings may be attributable to the heterogeneity of MDD; in fact, several studies have documented associations between BMI and mainly the atypical (非典型的) subtype of MDD. Using a MR approach, we investigated the potential causal role of obesity in both the atypical subtype and its five specific symptoms assessed according to the Statistical Manual of Mental Disorders (DSM), in two large European cohorts, CoLaus|PsyCoLaus (n = 3350, 1461 cases and 1889 controls) and NESDA|NTR (n = 4139, 1182 cases and 2957 controls). We first tested general obesity measured by BMI and then the body fat distribution measured by waist-to-hip ratio (WHR). Results suggested that BMI is potentially causally related to the symptom increase in appetite, for which inverse variance weighted, simple median and weighted median MR regression estimated slopes were 0.68 (SE = 0.23, p = 0.004), 0.77 (SE = 0.37, p = 0.036), and 1.11 (SE = 0.39, p = 0.004). No causal effect of BMI or WHR was found on the risk of the atypical subtype or for any of the other atypical symptoms. Our findings show that higher obesity is likely causal for the specific symptom of increase in appetite in depressed participants and reiterate (重申；反复地做) the need to study depression at the granular (颗粒的；粒状的) level of its symptoms to further elucidate (阐明；说明) potential causal relationships and gain additional insight into its biological underpinnings (基础，支柱).

没有发现BMI或WHR对非典型亚型或任何其他非典型抑郁症状的风险有因果影响

较高的肥胖水平可能是导致抑郁者食欲增加的具体症状的原因

易感：predisposition

See you tomorrow