A team from Imperial College London studied 4,857 people without diabetes between 1989 and 1991 and followed them up 20 years later. In total, 14% of those of European heritage developed diabetes, compared with 33% of those of Indian Asian heritage and 30% of those of African Caribbean heritage.
This equates to a doubling of diabetes risk among those of Indian Asian and African Caribbean heritage. The risk was 2.88-times higher for Indian Asian men, 1.91-times higher for Indian Asian women, 2.23-times higher for African Caribbean men and 2.51-times higher for African Caribbean women.
The researchers found that differences in baseline insulin resistance and truncal obesity largely accounted for the excess risk among ethnic minority women.
But, even after accounting for differences in insulin resistance and truncal obesity, Indian Asian and African Caribbean men still face twice the risk of developing diabetes.
‘Strikingly, we show that despite our comprehensive measures, the ethnic minority excess of incident diabetes in men (both Indian Asians and African Caribbeans) cannot be explained, whereas it can be explained for women.’
The researchers also said the reasons behind the greater insulin resistance among ethnic minorities were still unclear. They argue it may be more appropriate to see differences in this risk as ‘protection from insulin resistance in individuals of European origin’.
The Imperial College team concluded: ‘Better assessment of risk factors or a search for novel factors are required if we are to understand why ethnic minority groups are at such high risk for diabetes.’