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OBJECTIVE-Low birth weight is consistently associated with an increased risk of type 2 diabetes in adulthood, but the individual contributions from poor fetal growth and preterm birth are not known. We therefore investigated the significance of these two factors separately.
RESEARCH DESIGN AND METHODS-We identified a cohort of subjects born preterm or with low birth weight at term at four major delivery units in Sweden from 1925 through 1949. A comparison cohort of subjects was identified from the same source population. Of 6,425 subjects in all, 2,931 were born at <37 weeks of gestation and 2,176 had a birth weight <2,500 g. Disease occurrence among participants was assessed through nationwide hospital registers from 1987 through 2006.
RESULTS-During follow-up, there were 508 cases of diabetes. Low birth weight was strongly negatively associated with risk of diabetes (P for trend <0.0001). Both short gestational duration and poor fetal growth were associated with later diabetes (P for trend <0.0001 and <0.0004, respectively). Very preterm birth (≤32 weeks of gestation at birth) was associated with a hazard ratio (HR) of 1.67 (95% CI 1.33-2.11) compared with term birth. Birth weights below 2 SDs of mean birth weight for gestational age were associated with an HR of 1.76 (1.30-2.38) compared with birth weights between the mean weight and the weight at 1 SD above the mean.
CONCLUSIONS-Our results suggest that the association between low birth weight and diabetes is due to factors associated with both poor fetal growth and short gestational age. Diabetes 58:523-526, 2009
Type 2 diabetes affects hundreds of millions of people worldwide, and the prevalence is rising (1). Several studies have found an association between low birth weight and type 2 diabetes (2-12). The predominant explanation for this association has been the so-called fetal origins hypothesis, which suggests that fetal malnutrition induces adaptive changes in fetal glucose metabolism that become lasting, thereby contributing to an increased risk of type 2 diabetes and heart disease in adult life (2,13).
The fetal origins hypothesis inherently assumes that low birth weight indicates fetal growth restriction rather than preterm birth. For ischemic heart disease and hypertension, this assumption has been found to be valid (14,15). In the case of type 2 diabetes, no study has assessed the hypothesis while distinguishing...