Clinical and sociodemographic correlates of body mass index in a large multicenter obsessive–compulsive disorder sample

Abstract Purpose This multicenter study aims to investigate associations between body mass index (BMI) and sociodemographic and clinical characteristics in a clinical sample of individuals with obsessive–compulsive disorder (OCD). Methods Data were analyzed from 947 adults diagnosed with OCD, recruited through the Brazilian Research Consortium on Obsessive–Compulsive Spectrum Disorders. BMI was calculated from self-reported weight and height and categorized according to WHO definitions. Sociodemographic and clinical data were obtained using standardized instruments. Associations between BMI and sociodemographic/clinical variables were examined using linear regression models. Results The mean BMI in the sample was 24.55 kg/m 2 (SD = 4.65), with 5.5% of participants classified as underweight, 58% as normal weight, 25% as overweight, and 11.5% as obese. In the multivariate linear regression model, higher BMI was significantly associated with older age ( β = 0.09, p < 0.001), current psychiatric treatment ( β = 1.4, p < 0.001), and binge eating disorder ( β = 4.4, p < 0.001). Lower BMI was significantly associated with female sex ( β = – 1.6, p < 0.001) and body dysmorphic disorder ( β = – 1.2, p = 0.005). No significant associations were found with educational level, OCD severity, comorbid depression, anxiety, bulimia, or anorexia. Conclusion Although BMI was unrelated to OCD severity, it was associated with demographic, clinical, and treatment-related variables, underscoring the need for evaluation beyond symptom-based assessment. Level of evidence: III, as it is based on an observational analytic design using a large cross-sectional multicenter sample.