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

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.