Marital status, self-rated health, and mortality: overestimation of health or diminishing protection of marriage?

This study challenges two well-established associations in medical sociology: the beneficial effect of marriage on health and the predictive power of self-rated health on mortality. Using The National Health Interview Survey 1986-2004 with 1986-2006 mortality follow-up (789,096 respondents with 24,095 deaths) and Cox Proportional Hazards Models, we find the protective effect of marriage against mortality decreases with deteriorating health so that the married and unmarried in poor health are at similar risk for death. We also find the power of self-rated health to predict mortality is higher for the married than for any unmarried group. By using ordered logistic regression models, we find thresholds shift such that, compared to the unmarried, the married may not report poorer health until developing more severe health problems. These findings suggest the married tend to overestimate their health status. These two phenomena (diminishing protection and overestimation) contribute to but do not completely explain each other.