Life-course socioeconomic position and change in quality of life among older adults: evidence for the role of a critical period, accumulation of exposure and social mobility

Background This study evaluates the influence of socioeconomic position (SEP) over the life course on change in health-related quality of life (HRQoL) in older adults. Methods A prospective cohort of 2117 individuals aged 60 years and over. In 2001, SEP was measured over the life course as social class in childhood (approximated by father's occupation), as educational level completed and as adult social class (occupation of household head). HRQoL was measured with the SF-36 health questionnaire. Changes from 2001 to 2003 in the scores for the physical component summary (PCS) and the mental component summary (MCS) of the SF-36 were calculated, and individuals were classified into three categories: decline (decrease of >5 points), no change (change of -5 to +5 points) and improvement (increase of >5 points) in HRQoL. Results After adjustment for baseline HRQoL, lifestyle, chronic illness, educational level and adult social class, low childhood social class was associated with a higher risk of both a decline and an improvement in the SF-36 PCS and MCS. The risk of decline in PCS and MCS and of improvement in MCS increased with the cumulative number of adverse SEP over the life course. Subjects who rose in social class from childhood to adulthood showed the greatest improvement on the SF-36 PCS and MCS. Conclusion These results on the relation between SEP and changes in HRQoL in older adults support the three models proposed to explain health inequalities over the life course: the existence of critical periods, the accumulation of adverse SEP and social mobility.