Association between body mass index and mental health problems among Taiwanese adults

Background: Obesity is a main threat to public health and also as a risk factor for chronic diseases. The relationship between body mass index (BMI) and mental health problem is well circumstantiated in Western countries. However, due to difference in culture, life style and physical activity practice, the findings of Western societies may not be inferred to Oriental countries. The aim of this retrospective cohort study is to evaluate the relationships between BMI and mental health problems among Taiwanese adults and to assess the impact of gender on this issue. Methods: Our study sample consisted of 12,862 adults aged 18 years or older from the 2001 National Health Interview Survey (NHIS), with all had consented to the linking of the survey data to their NHI claims records. We divided the mental health problems into five major categories, namely as dementia and other cognitive disorders, mood disorders, schizophrenia, physiological malfunction arising from mental factors, and anxiety disorders. Logistic regression was used to evaluate the odds ratio. Results: Compared to normal weight men, underweight men had significantly higher risk of delirium, dementia, and other cognitive disorders (OR=2.87, 95% CI: 1.24-6.67). Significantly higher association was found in women between obesity and schizophrenia, with OR of schizophrenia was 5.74 (95% CI: 1.61-20.51) for obese class II women. Conclusion: These analyses highlight that there exists a gender interaction when examining the association between BMI and mental health problems.