IntroductionObstructive sleep apnea (OSA) is characterized by a complete or partial obstruction of the upper airway, along with hypoxemia, microarousals, and sleep fragmentation. Compelling evidence has clarified a bidirectional correlation between OSA and diabetes mellitus (DM). This paper was to assess the link between OSA and DM via meta‐analysis, consisting of type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM).Materials and MethodsFour databases (PubMed, Cochrane Library, Embase, and CNKI) were screened from inception to March 2024 for observational studies of OSA and DM, including case–control studies and cohort studies. Bidirectional associations between OSA and DM were analyzed, consisting of T1DM and T2DM. Random‐effect models were employed to determine the pooled odds ratio (OR) and 95% confidence intervals (CIs) to compare prevalence. Traditional subgroup analyses were implemented. Review Manager 5.3 and Stata 16.0 were utilized for data analyses.ResultsThirty‐five studies were enrolled, including 12 prospective cohort studies, 4 retrospective cohort studies, and 19 case–control studies. DM prevalence was notably higher in OSA patients than in non‐OSA patients (OR: 2.29, 95% CI: 1.93–2.72), and OSA prevalence was notably higher in DM patients than in non‐DM patients (OR: 2.12, 95% CI: 1.73–2.60). Subgroup analysis uncovered that DM prevalence in the OSA population was more significant in the group <50 years (OR: 3.28, 95% CI: 2.20–4.89) and slightly decreased in the group >50 years (OR: 1.82, 95% CI: 1.38–2.40).ConclusionsThe meta‐analysis reveals a bidirectional link between OSA and DM.