14-year diabetes incidence: the role of socio-economic status.

BACKGROUND

Diabetes prevalence is associated with low socioeconomic status (SES), but less is known about the relationship between SES and diabetes incidence.

DATA AND METHODS

Data from eight cycles of the National Population Health Survey (1994/1995 through 2008/2009) are used. A sample of 5,547 women and 6,786 men aged 18 or older who did not have diabetes in 1994/1995 was followed to determine if household income and educational attainment were associated with increased risk of diagnosis of or death from diabetes by 2008/2009. Three proportional hazards models were applied for income and for education--for men, for women and for both sexes combined. Independent variables were measured at baseline (1994/1995). Diabetes diagnosis was assessed by self-report of diagnosis by a health professional. Diabetes death was based on ICD-10 codes E10-E14.

RESULTS

Among people aged 18 or older in 1994/1995 who were free of diabetes, 7.2% of men and 6.3% of women had developed or died from the disease by 2008/2009. Lower-income women were more likely to develop type 2 diabetes than were those in high-income households. This association was attenuated, but not eliminated, by ethno-cultural background and obesity/overweight. Associations with lower educational attainment in unadjusted models were almost completely mediated by demographic and behavioural variables.

INTERPRETATION

Social gradients in diabetes incidence cannot be explained entirely by demographic and behavioural variables.