Subjective measures of health and all-cause mortality - the Rotterdam Study

Background. Subjectively assessed health is related to mortality. Various subjective indicators of health have been studied, but it is unclear whether perceived physical functioning or mental health best accounts for the relation with mortality. Method. We studied the relation of subjective measures of health with all-cause mortality in 5538 participants of age 55 to 96 years at baseline from the Rotterdam Study. Various instruments of subjectively assessed health were used, that included basic activities of daily living (BADL), instrumental activities of daily living (IADL), quality of life (QoL), positive affect, somatic symptoms and negative affect. All participants completed questionnaires for each subjective measure of health and were followed for mortality for a mean of 12.2 (S.E. = 0.09) years. Cox regression analysis was conducted in the total sample. Results. In this cohort, 2021 persons died during 48 534 person-years of follow-up. All measures of subjective health were related to mortality after adjusting for age, gender, education, cognition, prevalent chronic diseases and cardiovascular risk [BADL hazard ratio (HR, calculated per Z-score) = 1.35, 95% confidence interval (CI) 1.29-1.41; IADL HR = 1.27, 95% CI 1.22-1.32; QoL HR = 0.85, 95% CI 0.81-0.89; positive affect HR = 0.92, 95% CI 0.88-0.96; somatic symptoms HR = 1.11, 95% CI 1.06-1.16; and negative affect HR = 1.05, 95% CI 1.01-1.10]. In the mutually adjusted model, only BADL (HR = 1.24, 95% CI 1.16-1.32) and IADL (HR = 1.10, 95% CI 1.04-1.17) remained independently associated with mortality. Conclusions.Measures of subjectively assessed health are important indicators of mortality. Our study shows that of the different measures of subjective health, perceived physical health predicts mortality over and above mental health. Conversely, the association between mental health and mortality may partly be explained by poor perceived physical health.