Do stressors explain the association between income and declines in self-rated health? A longitudinal analysis of the National Population Health Survey.

Although there is considerable evidence documenting the relationship between lower socioeconomic status (SES) and poorer health, longitudinal research is needed to study mechanisms that may explain this relationship. This study investigated whether income was associated with decline in self-rated health over a 2-year period and whether stressors mediated part of this social gradient. Participants in the National Population Health Survey (NPHS) who rated their health as excellent, very good, or good in 1994 and 1995 were followed over 2 years. Analyses demonstrated that individuals in the 2 lowest household income quintiles had significantly greater odds of experiencing a decline in health status as compared to the highest quintile. Seven of 8 reported stressors at baseline were each associated with a significantly increased odds of experiencing a decline in self-rated health. Furthermore, these stressors explained 16% and 10% of the relationship between the lowest and 2nd lowest income quintiles and decline in self-rated health, respectively. These results suggest that stressors may be 1 mechanism underlying the social gradient in health.