Insulin sensitivity declines more slowly in whites than South Asians
South Asians of Indian, Pakistani or Bangladeshi origin experience a sharper decline in insulin sensitivity before a diabetes diagnosis compared with whites, according to a presentation at the 50th European Association for the Study of Diabetes Annual Meeting.
Adam Tabák, MD, PhD, of the University College of London, and colleagues used data from the Whitehall II study that included 95 South Asian and 724 white participants who developed type 2 diabetes during follow-up between 1992 and 2009 to determine ethnic differences in fasting plasma glucose, 2-hour postload plasma glucose (2hPG), long-transformed homeostasis model assessment insulin sensitivity (HOMA-S) and secretion (HOMA-B) before the diagnosis.
Compared with whites (10.2%), there was nearly a four times increased risk for incident diabetes among South Asians (26.4%) during follow-up (P<.001). South Asians also had a faster increasing FPG trajectory before diagnosis (0.34 mmol/L per decade increase; P=.022) as well as higher FPG levels at diagnosis (0.36 mmol/L higher; P=.007) compared with whites.
Fifteen years before diagnosis, South Asians had significantly lower insulin sensitivity compared with whites; this difference further increased until diagnosis. HOMA-B trajectories increased among both groups until 7 years before diagnosis; this was not significant in South Asians and significantly faster among whites.
“We conclude that if we could confirm this increased risk and earlier onset of type 2 diabetes among south Asians,” Tabák said during his presentation. “Fasting glucose rises earlier and increases faster among south Asians, suggesting that earlier detection may be possible in south Asians, providing a longer window of opportunity for preventive efforts. Insulin sensitivity is also lower among south Asians at least a decade before diagnosis and falls more rapidly, confirming the essential role of insulin sensitivity in the development of type 2 diabetes. In contrast to whites, who could increase insulin secretion up to 7 years before diagnosis, this compensatory mechanism is hardly seen in south Asians.”
For more information:
TabáK AG. Abstract #61. Presented at: 50th EASD Annual Meeting; Sept. 16-19, 2014; Vienna.
Disclosure: See the abstract for a complete list of the researchers’ relevant financial disclosures.