Signs of a chronic, low-grade inflammation precede the development of type II, or adult onset, diabetes, according to results from a nationwide study. The new finding could lead to earlier detection of those at risk of the disease.
“The results are persuasive evidence that inflammation is at least part of the cause of diabetes,” says study coauthor Paul M. Ridker of Brigham and Women’s Hospital in Boston.
Type II diabetes occurs when people become resistant to their own insulin and can’t regulate the concentration of sugar in their blood.
The researchers examined a subset of women in an ongoing study of heart disease. In the first 4 years of the study, 188 women in this subset developed diabetes. The researchers compared these women’s medical records to those of 362 participants of similar ages without diabetes.
Comparisons of blood samples taken from both groups at the beginning of the study revealed that women who had had higher concentrations of two biochemical markers of inflammation were more likely to eventually develop type II diabetes. The researchers accounted for other risk factors for diabetes, such as obesity and high blood pressure.
The quarter of women whose blood had the highest concentrations of C-reactive protein, or CRP, were 4.2 times as likely to have diabetes after 4 years as were the quarter of women with the lowest concentrations. The quarter of women with the highest concentrations of IL-6 were 2.3 times as likely to have developed the disease, Ridker and his colleagues report in the July 18 Journal of the American Medical Association.
High concentrations of CRP have been correlated with a risk of heart disease (SN: 6/14/97, p. 374: http://www.sciencenews.org/sn_arc97/6_14_97/bob1.htm) and with being overweight (SN: 5/1/99, p. 278). Ridker says that this and other studies suggest that inflammation is the underlying factor linking obesity, heart disease, and diabetes. Other researchers question whether inflammation causes these diseases or merely signals their early stages.