Determinants of socioeconomic differences in change in physical and mentalfunctioning

Continuous decline in functioning is not an inevitable consequence of agein g, as some individuals maintain high levels of functioning to old age. The origins of functional problems in old age are not only related to current c ircumstances, but may be traced back to earlier life-experiences. Previous analyses show that change in functioning is related to socioeconomic status , but it is uncertain to what extent these differences can be accounted for by the same health behaviours and material and psychosocial factors that a re related to socioeconomic differences in morbidity and mortality. This pa per investigates socioeconomic differences in change in mental and physical functioning in a relatively young and healthy population over a three year follow-up period. The data come from the Whitehall II Study of London base d civil servants aged 39-63 in 1991-93. We measured functioning with the Sh ort Form 36 (SF-36) General Health Survey and socioeconomic status by civil service employment grade. Among lower employment grade men the odds ratio of being in the quartile of rapid decline in mental and physical functionin g was 1.79 and 1.56 respectively. For women the odds ratio for physical fun ctioning was 1.34, but employment grade differences in mental functioning w ere inconsistent. Among men health behaviours were the most important deter minants of employment grade differences in physical functioning change. In addition, material problems and job decision latitude accounted for employm ent grade differences in physical as well as mental functioning change. How ever, among women employment grade differences in change in physical functi oning can not be accounted for with these risk factors. Analyses of change in determinants may provide further insight into the underlying pathways. E arly detection of functional decline and intervention may be a key to bette r functioning in ageing populations. (C) 1999 Elsevier Science Ltd. All rig hts reserved.