Mental effect of cholesterol in males: protective effect?

While the benefits of low cholesterol for physical health are not in doubt, a potential negative aspect of low cholesterol for mental health is suggested by several studies. To examine the association between cholesterol and mental health, the authors performed an observational study.

From April 1995 to March 2002, a series of questionnaires pertaining to physical activity, food consumption, alcohol, coffee, smoking, and mental health (12 item-version of General Health Questionnaire: GHQ-12) were administered to 1972 employees in Japan. Subjects with less than 150 mg/dL of total cholesterol (very low cholesterol cohort) and other subjects (control cohort) were followed up for one to six years, and their mental health compared using GHQ caseness (GHQ-12 scores more than 3).

Kaplan-Meier survival curves revealed that the very low cholesterol cohort had significantly greater GHQ caseness than the control cohort. Notably, this finding applied to males but not to females. After adjustment for general health, Cox's proportional hazards regression model confirmed this association in males only. The survival curves of control cohort were significantly different between males and females whereas those of very low cholesterol cohort were not.

GHQ caseness was regarded as "death" in the survival analysis. As such, it is not possible to differentiate between transient and persistent mental dysfunction and therefore may lead to overestimation of GHQ caseness over observational years.

The present findings suggest that very low cholesterol may be associated with worse mental health in males and conversely and interestingly indicate that moderate (but not very low) cholesterol levels may protect mental health in males.