Abdominal Obesity Indices as Predictors of Psychiatric Morbidity in a Large-Scale Taiwanese Cohort

Background/Objectives: Obesity has been linked to a number of diseases, including depression and anxiety. In addition to the commonly used body mass index (BMI) and waist circumference, many obesity-related indices have been proposed. We aimed to investigate the associations between 10 obesity-related indices and psychiatric morbidity in a large cohort of 121,601 Taiwanese participants. Methods: This cross-sectional study analyzed data from 121,601 adults aged 30–70 years enrolled in the Taiwan Biobank between 2012 and 2023. The mean age of the participants was 50 years, and the 10 obesity-related indices were BMI, waist circumference, waist-to-height ratio, waist-to-hip ratio, abdominal volume index, body roundness index, lipid accumulation product, visceral adiposity index, conicity index and triglyceride glucose index. Psychiatric morbidity, defined as the presence of depressive or anxiety symptoms, was identified using self-reported, physician-diagnosed depression, Patient Health Questionnaire 2-item (PHQ-2) score ≥ 3, or Generalized Anxiety Disorder 2-item (GAD-2) score ≥ 3. Multivariable logistic regression models were used to assess associations between each obesity-related index and psychiatric morbidity. Results: Psychiatric morbidity was observed in 5414 (5%), 1375 (3.0%) and 4039 (5%) individuals in the whole cohort, male participants and female participants, respectively. After adjusting for variables, all of the obesity-related indices were significantly associated with psychiatric morbidity, except for BMI in the male subjects. There were no significant interactions between sex and these 10 obesity-related indices. Conclusions: We found significant associations between multiple obesity-related indices and psychiatric morbidity; as these indices are simple and routinely collected, they may help identify individuals at higher psychological risk in population settings. Further research is warranted to clarify underlying mechanisms and their potential utility in screening or prevention.