Self-rated ill-health strengthens the effect of biomedical risk factors in predicting stroke, especially for men -- an incident case referent study

Abstract

Objectives: To examine how self-rated ill-health interacts with biomedical stroke risk factors in predicting stroke and to explore differences between men and women and educational groups.

Design: An incident case-referent study where the study subjects had participated in a prior health survey.

Setting: Nested within the Västerbotten Intervention Program (VIP) and the Northern Sweden MONICA cohorts.

Subjects: The 473 stroke cases had two referents per case, matched for age, sex and residence, from the same study cohorts.

Results: Self-rated ill-health independently increased the risk of stroke, specifically for men. The interaction effect between self-rated health and biomedical risk factor load was greater for men than for women. The attributable proportion due to interaction between having a risk factor load of 2+ and self-rated ill-health was 42% for men and 15% for women. Better-educated individuals with self-rated ill-health and two or more of the biomedical risk factors had a higher risk of stroke than the less educated. Calculations of the respective contribution to the stroke cases of self-rated health, hypertension and smoking showed that self-rated ill-health had a role in 20% of the cases and could alone explain more than one-third of the cases among those who rated their health as bad, more so for men than for women.

Conclusions: The results underscore the importance of including both a gender and a social perspective in discussing the role of self-rated health as a predictor of disease outcome. Physicians must be more gender sensitive when discussing their patient's own evaluation of health in relation to biomedical risk factors.