Excess maternal transmission and familial aggregation of Type 2 diabetes in Sri Lanka

INTRODUCTION: An excess of maternal transmission of Type 2 diabetes mellitus has been reported in Europid populations, but not in South India. METHOD: A questionnaire-based survey was carried out in 1000 (502 male) people with Type 2 diabetes to establish whether there is an excess of maternal transmission and familial aggregation in a Sri Lankan population. RESULTS: Mean age of onset was 47+/-12 (+/-S.D.) years and duration of diabetes was 9+/-7 years. Thirty-seven percent reported parents with diabetes, 46.9% had no parents with diabetes, 16.1% did not know the diabetes status of at least one parent and there was no diabetes in the other. Of the probands, 59.4% had at least one affected relative. When both parents' diabetes status was known and only one was affected, diabetes was more common among mothers (n = 156) than fathers (n = 125) of probands (P < 0.001). A further 54 probands had both parents with diabetes. Mean age of onset and duration of the disease among probands with parental diabetes was 43.1+/-(11.1) and 9.6+/-(6.8). In the previous generation, 21.2% of maternal grandmothers and 17.3% of maternal grandfathers in the maternal diabetes group and 4.8% of maternal grandmothers and 17% of maternal grandfathers in the paternal diabetes group had diabetes. Diabetes in siblings and children was more common in those with mothers who had diabetes (53.8% and 4.5%) when compared with those in whom fathers had diabetes (42.4% and 1.6%) (P < 0.0001 and P < 0.01). CONCLUSION: Familial aggregation and excess maternal transmission were observed in people with Type 2 diabetes in Sri Lanka.