[Small area-based socio-economic indicators in the study of inequalities in health]

To assess whether 2 area-level socioeconomic indicators (one single and the other composite) are able to detect social inequalities in health.

We used the Health Interview Survey of Barcelona, 1992. Perceived health status, the presence of chronic conditions, smoking, pap test, educational level and social class were analyzed. As area-level indicators, the percentage of unemployment and a deprivation index at census tract level were obtained from the 1991 census. The associations between area-based socioeconomic indicators and individual-level socioeconomic position, as well as the associations among both types of socioeconomic indicator and health, were analyzed.

A clear positive association was found between small area-based socioeconomic indicators and individual-level indicators. Similar effects were observed for different health outcomes among men as well as among women. For most of the outcomes analyzed, the differences were greater with the deprivation index than with unemployment. Thus, in men the age-adjusted odds ratio (ORa) of average, poor or very poor perceived health status was 2.0 (95% CI, 1.4-2.9) in the most disadvantaged unemployment quartile in relation to the least disadvantaged quartile while with the deprivation index the ORa was 2.7 (95% CI, 1.9-3.9). For women these ORa were 1.8 (95% CI, 1.4-2.4) and 2.4 (95% CI, 1.8-3.2), respectively.

Area-based socioeconomic indicators, such as those available through the Spanish census, can be applied in all members of a population and are useful for detecting social inequalities in health.