Obesity and Chronic Physical Illness: Excess Risk Associated with Mental Illness

OBJECTIVE: Examine the excess risk conferred by mental illness on the relationship between obesity and chronic physical illnesses among adults aged between 22 and 64.

METHODS: Cross-sectional data are from the nationally representative household survey, Medical Expenditure Panel Survey, 2005 (N = 16,237). Body mass index (BMI) was used to classify sample adults as normal, overweight, and obese. Mental illness consisted of depression, anxiety disorders, attention deficit disorders, personality disorders, schizophrenia and other mental disorders. Chronic physical illnesses included asthma, arthritis, chronic obstructive pulmonary disease (COPD), diabetes, gastroesophageal reflux disease (GERD), hypertension, heart disease, osteoporosis, and thyroid disorders. Chi-square tests and separate logistic regressions were performed to analyze the relationship between obesity and chronic physical illness.

FINDINGS: Overall, 18% reported having a mental illness. Rates of obesity were higher (36%) among those with mental illness compared to those without any mental illness (27%). After adjusting for demographic, socio-economic status, health status, and lifestyle behaviors, adults who reported any mental illness and obese were more likely to have chronic physical illnesses (asthma, arthritis, COPD,GERD, hypertension, and heart disease) compared to those with obesity and no mental illness. The adjusted odds ratios of obesity and mental illness ranged from 1.70 to 1.50 (p < .01). Mental illness did not alter the relationship between obesity and other chronic illnesses (osteoporosis, diabetes, and thyroid disorders).

CONCLUSION: The presence of any mental illness is associated with increased risk of certain chronic physical illnesses.