Diabetes mellitus in urban and rural communities in Papua New Guinea. Studies of prevalence and plasma insulin.

Oral glucose tolerance tests (75 g) in 185 urban residents of Port Moresby and 105 ethnically similar rural villagers showed that 15.8% of urban residents had diabetes mellitus (two hour plasma glucose > 11.0 mmol/l and a total of 22% were glucose intolerant (plasma glucose > 9.0 mmol/l), compared with 1.0% and 5.5% in rural people. - Urban men and women were significantly fatter than rural people, but within each population glucose tolerance was not significantly related to weight or to age, although the numbers of old people studied were small. Compared to Australians the Papua New Guinea subjects had a higher fasting plasma insulin (16.5 vs 10.7 microU/ml, p = < 0.05); independent of weight fasting plasma insulin was significantly higher in the rural than urban people studied. After the glucose load, plasma insulin and glucose levels were positively correlated in rural people. In contrast, for the urban group the relation best fitted a quadratic function, with decline in plasma insulin at high levels of glucose. - The prevalence of diabetes in urbanised Melanesians in Papua New Guinea appears similar to other South Pacific countries.