COWS MILK CONSUMPTION, DISEASE-ASSOCIATED AUTOANTIBODIES AND TYPE-1 DIABETES-MELLITUS - A FOLLOW-UP-STUDY IN SIBLINGS OF DIABETIC CHILDREN

Evidence from case-control studies for the diabetogenicity of introduc tion of cow's milk-based formulas at early age in infancy is inconclus ive. We followed siblings of children with Type 1 diabetes mellitus (T ype 1 DM) to investigate a possible relationship between cow's milk co nsumption during infancy or later in childhood and the emergence of di abetes-associated autoantibodies and progression to clinical Type 1 DM . A cohort of 725 initially unaffected 0 to 25-year-old siblings of 80 1 index children with Type 1 DM diagnosed in 1986-1989 participated in the study (82 % of those invited). The siblings were observed for Typ e 1 DM associated autoantibodies at intervals of 3-12 months for 4 yea rs, starting from the diagnosis of Type 1 DM in the index child. The f ollow-up for Type 1 DM started at the same time and ended on 31 Octobe r 1995. The combined prevalence of Type 1 DM associated autoantibodies (islet cell antibodies (ICA), insulin autoantibodies (IAA), CAD autoa ntibodies (GADA), and/or antibodies to the insulinoma associated cDNA2 protein (IA-2A)) was 13.6 % (95/697) at the beginning of the study. O f the initially seronegative siblings, 7.5 % (45/602) converted to ant ibody positivity during 4 years, and of all siblings 4.6 % (33/725) de veloped Type 1 DM during the total follow-up time. The age at introduc tion of supplementary milk feeding was not significantly related to se roconversion to positivity for Type 1 DM associated autoantibodies or to the development of Type 1 DM in the siblings. When adjusted for age , sex, infant feeding patterns, and maternal age and education, high m ilk consumption in childhood (greater than or equal to 3 glasses daily ) was associated with more frequent emergence of Type 1 DM-associated autoantibodies than low consumption (<3 glasses daily) (adjusted odds ratio 3.97, 95 % confidence interval 1.3-11.7, p = 0.01). There was a non-significant association between high milk consumption and progress ion to clinical Type 1 DM (adjusted hazard ratio 2.75, 95 % confidence interval 0.9-8.4, p = 0.07). To conclude, this study suggests that hi gh consumption of cow's milk during childhood may be associated both w ith seroconversion to positivity for diabetes-associated autoantibodie s and progression to clinical Type 1 DM among siblings of children wit h diabetes. (C) 1998 John Wiley & Sons, Ltd.