Assessing the Potential Shared Genetic Aetiology between Body Mass Index (BMI) and Sleep duration

Observational studies find an association between body mass index (BMI) and self-reported sleep duration in adults such that a higher BMI is associated with shorter duration of sleep. However, the key question here is... [ view full abstract ]

Observational studies find an association between body mass index (BMI) and self-reported sleep duration in adults such that a higher BMI is associated with shorter duration of sleep. However, the key question here is whether this relationship is causal, in either direction. Recently, findings from a Mendelian randomisation study in the UK Biobank suggest that a higher BMI does not in fact cause short sleep duration. Thus, it is likely that there are alternative biological pathways through which BMI and sleep duration are associated, but this has not been examined in depth, to date. To investigate this further we created several polygenic risk scores (PRSs) of BMI and examined their association with self-reported sleep duration in a combination of individual participant data (IPD) and summary-level data, with a total sample size of ~140,000. We find that, although a PRS of BMI is negatively associated with sleep duration, this explains a very small proportion of its variance. We will present detailed findings alongside a discussion of these, with reference to previous research and potential for future work.