Cow's milk consumption, HLA-DQB1 genotype, and type 1 diabetes - A nested case-control study of siblings of children with diabetes

The evidence for the putative role of cow's milk in the development of type 1 diabetes is controversial, We studied infant feeding patterns and childh ood diet by structured questionnaire (n = 725) and HLA-DQBI genotype by a p olymerase chain reaction-based method (n = 556) in siblings of affected chi ldren and followed them for clinical type 1 diabetes, In a nested case-cont rol design in a population who had both dietary and genetic data available, we selected as cases those siblings who progressed to clinical diabetes du ring the follow-up period (n = 33), For each case, we chose as matched cont rol subjects siblings n ho fulfilled the following criteria: same sex, age within 1 gear, not from the same family, the start of the follow-up within 6 months of that of the respective ease, and being at risk for type 1 diabe tes at the time the case presented with that disease(n = 254). The median f ollow- up time was 9.7 years (range 0.2-11.3). Early age at introduction of cow's milk supplements was not significantly associated with progression t o clinical type 1 diabetes (relative risk adjusted for matching factors, ma ternal education, maternal and child's ages, childhood milk consumption, an d genetic susceptibility markers was 1.60 [95%, CI 0.5-5.1]). The estimated relative risk of childhood milk consumption for progression to type 1 diab etes was 5.37 (1.6-18.4) when adjusted for the matching and aforementioned sociodemographic factors, age at introduction of supplementary milk feeding , as well as for genetic susceptibility markers. In conclusion, our results protide support for the hypothesis that high consumption of cow's milk dur ing childhood can be diabetogenic in siblings of children with type 1 diabe tes. However, further studies are needed to assess the possible interaction between genetic disease susceptibility and dietary exposures in the develo pment. of this disease.