Deprivation and cause specific morbidity: evidence from the Somerset and Avon survey of health.

OBJECTIVE: To investigate the association between cause specific morbidity and deprivation in order to inform the debates on inequalities in health and health services resource allocation.

DESIGN: Cross sectional postal questionnaire survey ascertaining self reported health status, with validation of a 20% sample through general practitioner and hospital records.

SETTING: Inner city, urban, and rural areas of Avon and Somerset.

SUBJECTS: Stratified random sample of 28,080 people aged 35 and over from 40 general practices.

MAIN OUTCOME MEASURES: Age and sex standardised prevalence of various diseases; Townsend deprivation scores were assigned by linking postcodes to enumeration districts. Relative indices of inequality were calculated to estimate the magnitude of the association between socioeconomic position and morbidity.

RESULTS: The response rate was 85.3%. The prevalence of most of the conditions rose with increasing material deprivation. The relative index of inequalilty, for both sexes combined, was greater than 1 for all conditions except diabetes. The conditions most strongly associated with deprivation were diabetic eye disease (relative index of inequality 3.21; 95% confidence interval 1.84 to 5.59), emphysema (2.72; 1.67 to 4.43) and bronchitis (2.27; 1.92 to 2.68). The relative index of inequality was significantly higher in women for asthma (P < 0.05) and in men for depression (P < 0.01). The mean reporting of prevalent conditions was 1.07 for the most deprived fifth of respondents and 0.77 in the most affluent fifth (P < 0.001).

CONCLUSIONS: Material deprivation is strongly linked with many common diseases. NHS resource allocation should be modified to reflect such morbidity differentials.