Body mass index and meniscal tears: Evidence from meta‐analysis of observational studies and Mendelian randomization

Summary Obesity is a potential risk factor for meniscal tear (MT). We utilized meta‐analysis of observational studies and Mendelian randomization (MR) analyses to elucidate the association between body mass index (BMI) and MT. In meta‐analysis, a search was performed on June 27, 2022, using PubMed and Embase databases. Odds ratios and 95% confidence intervals were extracted from included studies. In MR analyses, the research utilized summary‐level data on BMI and MT obtained from Genetic Investigation of Anthropometric Traits and the FinnGen Consortium, respectively. In meta‐analysis, four studies comprising 826,383 participants were included. The pooled odds ratio of MT in the high BMI group was 1.32 (95% confidence interval, 0.83–2.09), compared with the nonhigh BMI group. The pooled odds ratio in the under 30 group was 1.76 (95% confidence interval, 0.61–5.03). In MR analyses, one standard deviation increase in genetically predicted BMI was associated with meniscus derangement as a chronic subtype of MT (odds ratio, 1.36; 95% confidential interval, 1.17–1.59). We found that a high BMI was not associated with an increased likelihood of MT based on meta‐analysis of observational studies; however, by complementing MR analyses, we elucidated the causality of BMI increase on meniscus derangement as a chronic subtype of MT.