Estimating the direct and indirect pathways between education and diabetes incidence among Canadian men and women: a mediation analysis

PURPOSE: To estimate the direct and indirect pathways between education and diabetes. METHODS: We examined the relative contribution of eight different pathways between education and diabetes incidence over a 9-year period in Ontario, Canada. Our data source was respondents (35-60 years of age) to the 2000-2001 Canadian Community Health Survey individually linked with physician and hospital administrative data. Our sample contained 11,899 participants with no previous diagnosis of diabetes. The direct and indirect effects of education level on incident diabetes were estimated using Aalen additive hazard models. RESULTS: Not having completed secondary education was associated with 120 extra diabetes cases per 10,000 men per year and 43 additional diabetes cases per 10,000 women per year, compared with having Bachelors education or higher. Body mass index accounted for 13 of the 120 extra diabetes cases among men, and 24 of the 43 additional diabetes cases for women. CONCLUSIONS: Of the mediating pathways examined in this paper, body mass index was the pathway through which the largest number of diabetes cases was mediated among men and women. A substantial number of excess diabetes cases among respondents with lower education levels, in particular among men, were not mediated through any of the eight pathways examined