A number of studies have shown that glucose tolerance falls with decreasing birth weight and that people with low birth weight and high body mass index (BMI) as adults are those at greatest risk of developing Type II (non-insulin-dependent) diabetes mellitus. No such studies have been carried out in African populations. Therefore we investigated the relation between glucose tolerance and birth weight in a group of 7-year-old black South Africans for whom longitudinal anthropometric data were available. Oral glucose tolerance tests (OGTTs) were carried out on 152 subjects and inverse correlations were found between birth weight and the total amount of insulin secreted during the first 30 min (r = -0.19, p = 0.04) and last 90 min (r = -0.19, p = 0.04) of the oral glucose tolerance test and also between birth weight and the 30 min glucose concentrations (r = -0.20, p = 0.02). Children born with low birth weights but who had high weights at 7 years had higher insulin concentrations and indices of obesity compared with those with low birth weights and low weights at 7 years. There were also positive correlations between weight velocity and BMI (r = 0.24, p = 0.02) and weight velocity and insulin resistance (r = 0.18, p = 0.04) as measured using homeostasis model assessment (HOMA). Thus, low birth weight in conjunction with rapid childhood gains in weight especially as subcutaneous fat, produces poor glucose tolerance in 7-year-old children and can make them susceptible to the development of Type II diabetes later in life.
PIP: A number of studies have shown that glucose tolerance declines with decreasing birth weight and that people with low birth weight and high body mass index (BMI) as adults are at the highest risk of developing type II (non-insulin-dependent) diabetes mellitus. The authors explored the relation between glucose tolerance and birth weight in a group of 7-year old Black South Africans for whom longitudinal anthropometric data were available. Oral glucose tolerance tests (OGTTs) were conducted on 152 subjects and inverse correlations were found between birth weight and the total amount of insulin secreted during the first 30 minutes and last 90 minutes of the oral glucose tolerance test, and also between birth weight and the 30 minute glucose concentrations. Children born with low birth weights, but who had high weights at age 7 years had higher insulin concentrations and indices of obesity compared with those with low birth weights and low weights at age 7 years. Positive correlations were also found between weight velocity and BMI, and weight velocity and insulin resistance as measured through homeostasis model assessment. Therefore, low birth weight together with rapid childhood weight gains, especially in subcutaneous fat, produces poor glucose tolerance in 7-year old children and can make them susceptible to the development of type II diabetes later in life.