Health expectancy in New Zealand, 1981-1991: social variations and trends in a period of rapid social and economic change.

STUDY OBJECTIVE: To assess social variations and trends in health expectancy over a period of rapid social and economic change. DESIGN: Cross sectional survey data on the association between social status--gender, socioeconomic class and ethnic group--and measures of health status at two points in time approximately a decade apart. The Sullivan method of calculating health expectancy was used. SETTING: The adult population of New Zealand in the periods 1980-81 and 1992-93. PARTICIPANTS: Representative samples of the adult civilian non-institutionalised population of 6,891 (1980-81) and 5,873 (1992-93) respectively. MAIN RESULTS: In comparison with life expectancy, adjusting for health status narrowed the gender gap but widened socioeconomic and ethnic differentials. These results were replicated for three measures--self reported health, mobility, and handicap--suggesting a robustness of outcome to specific indicators. Comparable data over the period of study were only available for the mobility measure. Increases in longevity appeared to be fully absorbed by minor disability. Ethnic and socioeconomic disadvantages remained static or widened for the 15-64 age group, suggesting a potential social polarisation in the disability transition. CONCLUSIONS: The operationalization of health expectancy appears to be rather robust to specific indicators. Health expectancy may provide a sensitive health impact assessment of social and economic policy. Existing theories of the disability transition may need to be modified to take account of social variation, at least in the special case of disability free health expectancy over the 15-64 age range.