BIRTH-WEIGHT AND NON-INSULIN-DEPENDENT DIABETES - THRIFTY GENOTYPE, THRIFTY PHENOTYPE, OR SURVIVING SMALL BABY GENOTYPE

Objective-To determine the prevalence of diabetes in relation to birth weight in Pima Indians. Design-Follow up study of infants born during 1940-72 who had undergone a glucose tolerance test at ages 20-39 year s. Setting-Gila River Indian community, Arizona. Subjects-1179 America n Indians. Main outcome measure-Prevalence of non-insulin dependent di abetes mellitus (plasma glucose concentration greater-than-or-equal-to 11.1 mmol/l two hours after ingestion of carbohydrate). Results-The p revalence was greatest in those with the lowest and highest birth weig hts. The age adjusted prevalences for birth weights <2500 g, 2500-4499 g, and greater-than-or-equal-to 4500 g were 30%, 17%, and 32%, respec tively. When age, sex, body mass index, maternal diabetes during pregn ancy, and birth year were controlled for, subjects with birth weights < 2500 g had a higher rate than those with weights 2500-4499 g (odds r atio 3.81; 95% confidence interval 1.70 to 8.52). The risk for subsequ ent diabetes among higher birthweight infants (greater-than-or-equal-t o 4500 g) was associated with maternal diabetes during pregnancy. Most diabetes, however, occurred in subjects with intermediate birth weigh ts (2500-4500 g). Conclusions-The relation of the prevalence of diabet es to birth weight in the Pima Indians is U shaped and is related to p arental diabetes. Low birth weight is associated with non-insulin depe ndent diabetes. Given the high mortality of low birthweight infants se lective survival in infancy of those genetically predisposed to insuli n resistance and diabetes provides an explanation for the observed rel ation between low birth weight and diabetes and the high prevalence of diabetes in many populations.