What determines Self-Rated Health (SRH)? A cross-sectional study of SF-36 health domains in the EPIC-Norfolk cohort.

BACKGROUND: Self-Rated Health (SRH) as assessed by a single-item measure is an independent predictor of health outcomes. However, it remains uncertain which elements of the subjective health experience it most strongly captures. In view of its ability to predict outcomes, elucidation of what determines SRH is potentially important in the provision of services. This study aimed to determine the extent to which dimensions of physical, mental and social functioning are associated with SRH.

METHODS: We studied 20,853 men and women aged 39-79 years from a population-based cohort study (European Prospective Investigation of Cancer study) who had completed an SRH (Short Form (SF)-1) measure and SF-36 questionnaire. SF-36 subscales were used to quantify dimensions of health best predicting poor or fair SRH within a logistic regression model.

RESULTS: In multivariate models adjusting for age, gender, social class, medical conditions and depression, all subscales of the SF-36 were independently associated with SRH, with the Physical Functioning subscale more strongly associated with poor or fair compared with excellent, very good or good health (OR 3.7 (95% CI 3.3 to 4.1)) than Mental Health (OR 1.4 (95% CI 1.2 to 1.5)) or Social Functioning subscales (OR 1.8 (95% CI 1.6 to 2.0)) for those below and above the median.

CONCLUSION: This study confirms that physical functioning is more strongly associated with SRH than mental health and social functioning, even where the relative associations between each dimension and SRH may be expected to differ, such as in those with depression. It suggests that the way people take account of physical, mental and social dimensions of function when rating their health may be relatively stable across groups.