Area-based socioeconomic status and mortality: the Ludwigshafen Risk and Cardiovascular Health study

Low individual socioeconomic status (SES) is a known risk factor for morbidity and mortality. A related measure is the area-based SES (abSES), which describes the average SES of a region. The association of measures of abSES with morbidity and mortality is less well studied.

The Ludwigshafen Risk and Cardiovascular Health study consists of 3316 patients hospitalized for coronary angiography between 1997 and 2000 at a tertiary care centre in Germany. Patients were followed up for a median of 10 years. Two measures of abSES were used: the regional purchasing index (PPI, data obtained from IQVIA GmbH) and the German Index of Socioeconomic Deprivation (GISD, developed by the Robert-Koch Institute). The association of abSES with disease and with mortality was analysed using logistic regression and Cox proportional hazards regression, respectively.

Study participants living in regions with higher abSES had lower HbA1c and high-sensitive C-reactive protein. A higher abSES was associated with lower prevalence of active smoking, vitamin D deficiency and diabetes mellitus. We further found significantly increased mortality for participants in the lowest PPI quartile (age- and sex-adjusted hazard ratio (95% CI) of 0.58 (0.38-0.90) as compared to the first quartile), and in the highest GISD tertile (HR of 1.32 (1.13-1.54) as compared to the first tertile).

Living in an area with a low abSES was associated with a higher burden of diabetes mellitus, a higher percentage of severe vitamin D deficiency, higher systemic inflammation and a significant increase in mortality.