Extended periods of daytime sleep increase risk of non-alcoholic fatty liver disease: Study

A new study by Qiao X and team suggests that sleeping for extended periods of time during the day may have a role in the development of non-alcoholic fatty liver disease (NAFLD). The findings of this study were published in the journal of Nature and Science of Sleep. A major public health concern is the growing prevalence of NAFLD and its myriad of consequences, which are mostly caused by the changes in food and lifestyle habits. Taking naps throughout the day is a common practice in many countries, especially China. It has not yet been conclusively determined if napping and the prevalence of NAFLD are causally related.

And so, conventional observational studies, including carefully designed prospective studies with sizable sample sizes, continue to be susceptible to residual confounding variables and the potential for reverse causation. Therefore, this study was conducted to examine how taking naps during the day might affect the likelihood of developing NAFLD by offering further insight into the causal relationship and helping to identify risk factors for the condition.

Mendelian randomization (MR) and meta-analysis were employed to combine observational and genetic data. Using 105 single-nucleotide polymorphisms (SNPs) linked to daytime napping habits, a two-sample MR analysis was carried out. Also, summary-level information about the outcomes of NAFLD was obtained from the extensive UK Biobank project. The association between extensive daytime napping and NAFLD was examined using network meta-analyses, and a subgroup analysis was also conducted.

This comprehensive study found significant links between sleeping throughout the day and non-alcoholic fatty liver disease. This systematic review and meta-analysis also showed that the individuals who slept for more than 30 minutes during the day had a higher chance of developing non-alcoholic fatty liver disease when compared to people who did not sleep. Additionally, MR analysis showed a significant correlation between a genetic predisposition for longer naps during the day and an elevated risk of NAFLD.

This MR study showed a link between midday sleeping and an increased chance of incident non-alcoholic fatty liver disease. Also, the individuals with NMA who slept for more than thirty minutes on average were shown to be at a higher risk of developing NAFLD than the individuals who napped for shorter periods of time or not at all.

Reference:

Qiao, X., Wang, X., Guo, L., & Pan, Q. (2024). Excessive Daytime Napping Increases the Risk of Non-Alcoholic Fatty Liver Disease: A Meta-Analysis and a Mendelian Randomization Study. In Nature and Science of Sleep: Vol. Volume 16 (pp. 1067–1074). Informa UK Limited. https://doi.org/10.2147/nss.s468444