Objective: Recent research indicates an association between obesity and psychopathology status, the nature of which remains unclear. We evaluated the mediating role of biochemical disturbances in this association among a treatment-seeking sample of obese individuals.
Method: The study enrolled 143 consecutive overweight and obese individuals (mean age 35±9 y) and 143 normal-weight controls (mean age 34±9 y), matched by age and sex. We measured psychopathology features using the Symptom Checklist 90-Revised (SCL-90-R), a standardized self-evaluation rating scale, and biochemical parameters (plasma cholesterol, triglyceride, and fasting glucose levels) of all participants. Nonlinear regression models were used to estimate the associations among obesity, psychopathology, and biochemical factors.
Results: Obesity was associated positively and significantly (P<0.05) with all of the SCL-90-R subscales, with the exception of anxiety and phobic anxiety, as well as with levels of plasma glucose, cholesterol (P<0.01), and triglycerides (P<0.001). Tests for mediation showed that obesity was significantly associated, for the mediators of plasma cholesterol [parameter estimate=-0.033, P<0.05] and triglycerides (parameter estimate=-0.059, P<0.05), only with hostility (parameter estimate=-0.024, P<0.05 and parameter estimate=-0.041, P<0.05, respectively).
Conclusions: Our data suggest that biological substrates that are critically related to obesity, such as dyslipidemia, may mediate, at least in part, the association between obesity and hostility.