Sedentary behavior, physical activity, sleep duration and obesity risk: Mendelian randomization study.

Area of Science:

• Genetics and Public Health
• Epidemiology
• Metabolic Disease Research

Background:

• Observational studies suggest links between sedentary behaviors (SB), physical activity (PA), sleep duration (SD), and obesity.
• Causal relationships between these factors and obesity remain unclear.

Purpose of the Study:

• To investigate the causal relationships between SB, PA, SD, and obesity using Mendelian randomization (MR).
• To identify specific sedentary behaviors that contribute to obesity risk.

Main Methods:

• Utilized MR with genetic variants as instrumental variables.
• Obtained genetic data from Genome-wide association studies (GWAS) and obesity data from FinnGen.
• Employed the IVW method with sensitivity analyses (Cochran Q, MR-Egger, MR-Radial) and eQTL analysis.

Main Results:

• Causal links were found between increased television watching, computer use, leisure screen time (LST), and driving, and a higher risk of obesity.
• No causal relationships were observed for SB at work, sedentary commuting, PA, or SD with obesity.
• eQTL analysis identified specific genes and SNPs associated with SBs in adipose tissues, implicating pathways like cortisol synthesis and insulin secretion.

Conclusions:

• Four specific sedentary behaviors (LST, television watching, computer use, driving) are causally linked to obesity.
• Findings offer insights for targeted interventions to combat obesity.
• Further research and public health initiatives focusing on reducing these specific SBs are recommended.