Individual and ecological factors related to the geographical variability of psychological distress among small areas: a multilevel analysis in Catalonia, Spain

BACKGROUND: To know the geographic distribution of the prevalence of psychological distress is important for mental health services planning. This study is aimed at identifying the individual factors and those related to the area of residence which may explain the geographic variability of psychological distress (by healthcare districts) in Catalonia. METHODS: The data was taken from the 1994 Catalonian Health Survey and from the 1996 Catalonia population statistics. The prevalence of psychological distress is estimated by age and sex and by healthcare district. In a two-level logic regression model, a study is made of the relationship between the individual variables (first level: health survey n = 12,455) and those of the area of residence (second level: the healthcare district, n = 46) to the geographic distribution of the prevalence of psychological distress. RESULTS: The significant variables at individual level are in men: age (45-64 years OR: 0.63 y > 64 years OR: 0.22), working status (no work OR: 1.60), number of chronic diseases (CD) (CD = 1 OR: 1.75 CD = 2 OR: 2.06 CD = 3-5 OR: 3.36 and CD > 5 OR: 8.9). In women: age (25-44 years OR: 0.63 45-64 years OR: 0.45 and > 64 years OR: 0.32), working status (no work OR: 1.30), number of chronic diseases (CD = 1 OR: 1.75 CD = 2 OR: 2.44 CD = 3-5 OR: 4.09 and CD > 5 OR: 11.14), and also the kind of parental household in women (single-parental OR: 1.42). The variables at the level of the area of residence are in migration (men OR: 1.55 and women OR: 1.68) and unemployment (men OR: 1.07 and women OR: 1.06). CONCLUSIONS: The individual factors do not suffice to explain the geographical variability of the prevalence of psychological distress, but the characteristics of the area of residence are also important.