Coffee consumption is inversely related to risk of type 2 diabetes (T2D). In contrast, an increased risk of latent autoimmune diabetes in adults (LADA) has been reported in heavy coffee consumers, primarily in a subgroup with stronger autoimmune characteristics. Our study aimed to investigate whether coffee consumption interacts with HLA genotypes in relation to risk of LADA.

This population-based study comprised incident cases of LADA (n=484) and T2D (n=1609), and also 885 healthy controls. Information on coffee consumption was collected by food frequency questionnaire. Odds ratios (ORs) with 95% CIs of diabetes were calculated and adjusted for age, gender, BMI, education level, smoking and alcohol intake. Potential interactions between coffee consumption and high-risk HLA genotypes were calculated by attributable proportion (AP) due to interaction.

Coffee intake was positively associated with LADA in carriers of high-risk HLA genotypes (OR: 1.14 per cup/day, 95% CI: 1.02–1.28), whereas no association was observed in non-carriers (OR: 1.04, 95% CI: 0.93–1.17). Subjects with both heavy coffee consumption (≥4 cups/day) and high-risk HLA genotypes had an OR of 5.74 (95% CI: 3.34–9.88) with an estimated AP of 0.36 (95% CI: 0.01–0.71; P=0.04370).

Our findings suggest that coffee consumption interacts with HLA to promote LADA.