From August 1998 to August 2002, we located 2584 (31.6 percent) of the initial cohort. A social worker performed home visits and recorded each subject’s occupation and level of education, physical activity, and alcohol and tobacco consumption. The subjects were asked to attend a clinic after an overnight fast for further investigations. Of the 1583 subjects (61.3 percent) who agreed to participate, 57 were excluded (24 were pregnant, 2 withdrew, and 31 were unreliably linked to earlier data), leaving 1526. In comparison with the original cohort, this cohort had 7 percent more male subjects, the rate of maternal literacy was 6 percent higher, the mean birth weight was 32 g higher, and the mean birth length was 2 mm longer. The height, weight, and body-mass index (the weight in kilograms divided by the square of the height in meters) in childhood and adolescence were approximately 0.1 SD lower than in the original cohort.
The subjects’ blood pressure, weight, height, waist and hip circumferences, and skinfold thicknesses (triceps and subscapular) were measured according to standardized techniques. Subjects were categorized as obese if their body-mass index was 30 or more.11 Two definitions of overweight were used, the standard World Health Organization11 cutoff value of a body-mass index of 25 and that recommended for Asians12 of 23.
A standard glucose-tolerance test with an oral 75-g anhydrous glucose load was administered.13 Plasma glucose concentrations in samples obtained after an overnight fast and 30 and 120 minutes after the ingestion of glucose (fasting, 30-minute, and 120-minute values) were analyzed by means of a glucose oxidase method (GOD-PAP, Randox) with a Beckman autoanalyzer. Aliquots of plasma were stored at −70°C for up to eight months, and insulin concentrations were measured by radioimmunoassay (Coat-a-Count insulin kit, Diagnostic Products). The intraassay and interassay coefficients of variation were less than 5 percent and less than 7.5 percent, respectively. Insulin resistance was calculated according to the homeostasis-model assessment.14 (link)The 30-minute increment in insulin — calculated as the (30-minute insulin concentration–the fasting insulin concentration)÷the 30-minute glucose concentration — was used as a measure of first-phase insulin secretion.15 (link) Impaired glucose tolerance was defined as a fasting plasma glucose concentration of less than 126 mg per deciliter (7.0 mmol per liter) and a 120-minute value of at least 141 mg per deciliter (7.8 mmol per liter); diabetes was defined as a fasting glucose concentration of at least 126 mg per deciliter or a 120-minute concentration of at least 200 mg per deciliter (11.1 mmol per liter).13 The All India Institute of Medical Sciences approved the study. Informed consent was obtained from each subject.
The subjects’ blood pressure, weight, height, waist and hip circumferences, and skinfold thicknesses (triceps and subscapular) were measured according to standardized techniques. Subjects were categorized as obese if their body-mass index was 30 or more.11 Two definitions of overweight were used, the standard World Health Organization11 cutoff value of a body-mass index of 25 and that recommended for Asians12 of 23.
A standard glucose-tolerance test with an oral 75-g anhydrous glucose load was administered.13 Plasma glucose concentrations in samples obtained after an overnight fast and 30 and 120 minutes after the ingestion of glucose (fasting, 30-minute, and 120-minute values) were analyzed by means of a glucose oxidase method (GOD-PAP, Randox) with a Beckman autoanalyzer. Aliquots of plasma were stored at −70°C for up to eight months, and insulin concentrations were measured by radioimmunoassay (Coat-a-Count insulin kit, Diagnostic Products). The intraassay and interassay coefficients of variation were less than 5 percent and less than 7.5 percent, respectively. Insulin resistance was calculated according to the homeostasis-model assessment.14 (link)The 30-minute increment in insulin — calculated as the (30-minute insulin concentration–the fasting insulin concentration)÷the 30-minute glucose concentration — was used as a measure of first-phase insulin secretion.15 (link) Impaired glucose tolerance was defined as a fasting plasma glucose concentration of less than 126 mg per deciliter (7.0 mmol per liter) and a 120-minute value of at least 141 mg per deciliter (7.8 mmol per liter); diabetes was defined as a fasting glucose concentration of at least 126 mg per deciliter or a 120-minute concentration of at least 200 mg per deciliter (11.1 mmol per liter).13 The All India Institute of Medical Sciences approved the study. Informed consent was obtained from each subject.
