Meningococcal disease and social deprivation: a small area geographical study in Gwent, UK.

Although meningococcal disease is known to be linked to characteristics of individuals associated with social deprivation, there is only limited evidence of a relation with area-based measures of deprivation. In a small area geographical study, we ascertained 295 confirmed or probable cases occurring between 1996 and 1999 in the socially diverse resident population of Gwent Health Authority, equating to an average annual rate of 13.2 per 100,000. Incidence rates of meningococcal disease increased from 8.1 per 100,000 in the least deprived fifth of enumeration districts to 19.8 per 100,000 in the most deprived fifth, a relative risk of 2.4 (95% CI 1.7-3.6). In Poisson regression, the percentage change in the incidence rate arising from a unit change in the enumeration district Townsend score, was 9.4% (95% CI 6.2-12.6%). Strongest associations were found for the under 5 age group, serogroup B disease and with the overcrowding variable component of the Townsend index. Our study quantifies the strength of the relation between meningococcal disease and social deprivation at small area level and provides further evidence of the need for action to reduce health inequalities.