BMI and well-being in people of East Asian and European ancestry: a Mendelian randomisation study.
Jessica O'LoughlinFrancesco CasanovaAmanda M HughesZammy Fairhurst-HunterLiming LiZhengming Chennull nullJack BowdenEd WatkinsRachel M FreathyLaura D HoweRobin G WaltersJessica TyrrellPublished in: Translational psychiatry (2023)
Previous studies have linked higher body mass index (BMI) to lower subjective well-being in adult European ancestry populations. However, our understanding of these relationships across different populations is limited. Here, we investigated the association between BMI and well-being in people of (a) East Asian and (b) European ancestry in the China Kadoorie Biobank (CKB) and UK Biobank (UKB), respectively. Mendelian randomisation (MR) methods were used to test the relationship between BMI with (a) health satisfaction and (b) life satisfaction. One-sample MR enabled us to test effects in men and women separately and to test the role of cultural contexts by stratifying our analyses by urban and rural home location in both China and the UK. Further, we implemented a control function method to test the linearity of the BMI-well-being relationship. We found evidence of different associations between BMI and well-being in individuals of East Asian versus European ancestry. For example, a genetically instrumented higher BMI tentatively associated with higher health satisfaction in people of East Asian ancestry, especially in females (ß: 0.041, 95% CI: 0.002, 0.081). In contrast, there was a robust inverse association between higher genetically instrumented BMI and health satisfaction in all European ancestry UKB participants (ß: -0.183, 95% CI: -0.200, -0.165, P difference < 1.00E-15). We also showed the importance of considering non-linear relationships in the MR framework by providing evidence of non-linear relationships between BMI and health and life satisfaction. Overall, our study suggests potential setting-specific causality in the relationship between BMI and subjective well-being, with robust differences observed between East Asians and Europeans when considering very similar outcomes. We highlight the importance of (a) considering potential non-linear relationships in causal analyses and (b) testing causal relationships in different populations, as the casual nature of relationships, especially relationships influenced by social processes, may be setting-specific.
Keyphrases
- body mass index
- weight gain
- healthcare
- public health
- mental health
- magnetic resonance
- physical activity
- contrast enhanced
- health information
- human health
- emergency department
- risk assessment
- type diabetes
- cross sectional
- metabolic syndrome
- health promotion
- high resolution
- sleep quality
- single molecule
- skeletal muscle
- climate change
- social media
- childhood cancer