Longitudinal investigation of objective and subjective indicators of socioeconomic status in the elderly

A large body of health care literature points to the importance of considering the effects of socioeconomic inequalities on health (Marmot, 2004). The primary aim of the present study is to investigate the role of both objective and subjective indicators of socioeconomic status (SES) in explaining health disparities over time among older adults. Data were drawn from the New Zealand Longitudinal Study of Aging, with complete data available for 1765 participants (Mean age = 61.16 years; SD=4.47). SES and demographic data were taken from 2006 (Time 1) and health data from 2006 and 2008 (Time 2). SES Markers: objective SES was assessed by two proxies - income and education, and subjective SES was measured by economic living standards index. Health Markers: Physical and mental health from Short Form 36, self-rated health and health-risk behaviours were used to assess health status. Various demographic variables were also measured. In comparison to objective SES (assessed by income and education), subjective SES (assessed by perceived economic living standards) came out to be a significant predictor of an array of health outcomes. Hierarchical linear regressions suggested that low subjective SES at Time 1 significantly predicted decrements in health at Time 2, after controlling for sociodemographic characteristics and baseline scores of health outcomes. The concept of economic living standards (as indexed by subjective SES) takes into account the different daily living circumstances and social experience in which people may use income and assets, including different needs and subjective aspirations. Thus, subjective SES is a better longitudinal predictor in explaining the health disparities in older adults than objective SES.