Modeling the relationship between perceived neighbourhood characteristics and adult hospitalization frequencies from a cross-sectional study

Interest in the quantitative effects of neighbourhood characteristics on urban health has recently increased in social epidemiology. Such effects are mostly studied employing multilevel models based on some definition of the neighbourhood. We investigate the statistical relationship between health and the neighourhood quality as perceived by individuals, thus avoiding the need of choosing a specific definition of neighbourhood. We use data from the Los Angeles Family and Neighbourhood Survey (L.A.FANS). We measure health status of an individual as the number of hospitalizations in the last two years. This number is related to individual carachteristics (including neighbourhood perceptions) through generalized additive models (GAM), focusing particularly on the Zero Inflated Poisson (ZIP), which is an unusual choice in this context. We also overcome to some extent the difficulties in interpreting the results from a GAM with a ZIP distribution by simulating predicted values under varying assumptions in order to reveal the relationship of interest. The analysis confirms that the quality of neighbourhood – as measured by perceptions of individuals – significantly relates to the health status of inhabitants – as measured by the number of hospitalizations.