Investigating the causal links between obstructive sleep apnea and gastrointestinal diseases mediated by metabolic syndrome through mendelian randomization.

Previous studies have pointed to a potential link between Obstructive Sleep Apnea (OSA) and gastrointestinal diseases, suggesting that this relationship might be influenced by the presence of Metabolic Syndrome. However, the exact role of these factors in determining gastrointestinal diseases has not been thoroughly explored. In our study, we utilized data from the Genome-wide Association Studies (GWAS) database, focusing on OSA, metabolic syndrome characteristics such as Body Mass Index (BMI), waist circumference, triglycerides, cholesterol, hypertension, type 2 diabetes, and common gastrointestinal diseases including chronic gastritis, gastric ulcers, irritable bowel syndrome, colorectal cancer, inflammatory bowel disease, cholecystitis, nonalcoholic fatty liver, and dyspepsia. By applying Single-variable and Multi-variable Mendelian randomization methods, we aimed to assess the correlation between OSA and gastrointestinal diseases and investigate whether this correlation is influenced by metabolic syndrome. Our findings revealed a strong association between OSA and an increased risk of chronic gastritis, gastric ulcers, inflammatory bowel disease, and nonalcoholic fatty liver disease. No significant connections were found with irritable bowel syndrome, colorectal cancer, cholecystitis, or dyspepsia. Additionally, OSA was linked to metabolic syndrome traits like BMI, waist circumference, triglycerides, hypertension, and type 2 diabetes. Further analysis showed that BMI, triglycerides, and hypertension were causally related to inflammatory bowel disease; BMI, waist circumference, hypertension, and type 2 diabetes to nonalcoholic fatty liver disease; and triglycerides, hypertension, and type 2 diabetes to chronic gastritis. The multivariable analysis indicated that hypertension mediates the relationship between OSA and chronic gastritis; BMI, triglycerides, and hypertension mediate the link between OSA and inflammatory bowel disease; and waist circumference mediates the connection between OSA and nonalcoholic fatty liver disease. To wrap up, this finding helps us understand how these issues might be related and stresses the role of metabolic syndrome in preventing them, which could lessen their effect on health.