Is there a relationship between non-insulin diabetes mellitus and birth order?

Our objective was to determine the prevalence of non-insulin dependent diabetes mellitus Type 2 Diabetes, in the province of Leon, Spain, and to investigate the relationship between birth order and the presence of diabetes. A cross-sectional study was therefore carried out on a stratified sample of the adult population (n = 569). The participants completed a socio-demographic questionnaire and an analysis of their basal capillary glycaemia and an oral glucose tolerance test (OGTT) after a 75 g load according to WHO recommendations. Type 2 diabetes prevalence was 5.62%. It was higher in subjects with a birth order above 4 than among those with a birth order below or equal to 4. (16.81% vs 2.85%, p < 0.001). This remained after adjusting for age. It was not proved that either sex, obesity or a family history of diabetes could amount to confusion factors. Greater values of fasting glycaemia (5.12 vs 4.73 mmol/l, p < 0.001) and less satisfactory post-OGTT glycaemic curves were also shown is subjects with a birth order > 4. Although it was not-possible to definitely conclude, from our study, that children born after the fourth birth have a greater risk of presenting alterations in their carbohydrate metabolism, there are indicators arguing for a more detailed study of such a possibility.