Increasing socio-economic inequality in type 2 diabetes prevalence--Repeated cross-sectional surveys in England 1994-2006

Abstract

Background: This study aimed to evaluate the association of rising type 2 diabetes prevalence with socio-economic inequality in diabetes. Methods: Data from the Health Survey for England were analysed for 1994, 1998, 2003 and 2006. This is a nationally representative annual survey of private households. Data for 41 643 individuals aged ≥35 years were included. The prevalence of self-reported diabetes diagnosed by a doctor was analysed in relation to household income, occupational social class and educational qualifications. Data were standardized for age using the European Standard Population for reference. Results: Prevalence of diagnosed diabetes increased in men from 3.74% in 1994 to 7.25% in 2006, and in women from 2.28% to 4.88%. In 1994, there were no associations between social class or educational level and diabetes prevalence evident. In 2006, there was evidence of a negative association in women [prevalence ratio for social class (IV + V vs. I) = 4.54, P-value for trend = 0.005; prevalence ratio for educational level (‘none’ vs. ‘A-levels’) = 1.96, P-value for trend = 0.001]. The Slope Index of Inequality (SII) for social class in women increased from –1.65 in 1994 to –4.95 [95% Confidence Interval (95% CI –8.52 to –1.38)] in 2006 and for level of education from –1.39 to –6.48 (95% CI –9.03 to –3.93). In men, diabetes prevalence was not associated with social class or level of education. Conclusion: Increasing prevalence of type 2 diabetes has been associated with an increase of socio-economic inequality in women. There was no socio-economic gradient observed in men.