Effects of ethnicity on glucose tolerance, insulin resistance and beta cell function in 223 women with an abnormal glucose challenge test during pregnancy

This study was conducted to investigate body-mass-index (BMI), insulin resi stance and beta cell. function in a group of pregnant women. Two hundred an d twenty-three consecutive women with an abnormal 50 g glucose challenge te st in the third trimester were studied. All underwent oral glucose toleranc e testing; 97 had a 100 g test and 126 a 75 g test. Fasting insulin was mea sured. Insulin resistance and beta cell function were calculated using the homeostasis model. Among the 136 Caucasian, 60 Asian, 11 Indian and 16 Arabic women studied, t here were no age differences. Arabic women had higher parity (p < 0.05). As ian women had lower BMI than Caucasian (p < 0.001), Indian (p < 0.01), and Arabic women (p < 0.01). Women with gestational diabetes had higher insulin resistance than women wi th normal glucose tolerance (2.9 +/- 4.0 vs 2.3 +/- 2.5 p = 0.025). Women w ith gestational diabetes tended to have lower beta cell function 199 +/- 20 3 vs 247 +/- 380 p = 0.08). Asian women had higher glucose levels than Cauc asian women after 50 g challenge (8.9 +/- 2.1 mmol/l vs 8.6 +/- 1.6; p = 0. 034). Asian women were more likely to have gestational diabetes than Caucas ian women (31.7% vs 14%; p = 0.02). Fasting glucose and insulin were compar able in Asian and Caucasian women. Mean insulin resistance and beta cell fu nction in Asian and Caucasian women were not significantly different. We concluded that Asian women had lower BMI than Caucasian women. Women wit h gestational diabetes were more insulin resistant. Insulin resistance and beta cell function in Asian and Caucasian women are similar. Gestational di abetes in Asian women is of similar aetiology to that seen in Caucasian wom en, but occurs at a lower BMI.