New Delhi, March 10: A protein linked for years to inflammation and heart disease may also be able to predict impending diabetes years before it shows up as high blood sugar, a new study from India suggests.
Researchers have found that a condition called pre-diabetes is associated with elevated levels of the C reactive protein (CRP) found in blood, but they also caution that it would still be premature to recommend it as a routine test to predict diabetes.
The CRP has previously been observed to rise in inflammation and infections and in diabetes. But the new study by researchers at the Institute of Genomics and Integrative Biology (IGIB) and the All India Institute of Medical Sciences (AIIMS) in New Delhi is the first in India to show that persons with impaired, or high, fasting glucose (IFT) and impaired glucose tolerance (IGT) — conditions labelled as pre-diabetes — have high CRP levels.
The findings will appear in a forthcoming issue of the journal Atherosclerosis.
“We’re exploring the connection between inflammation and pre-diabetes,” said Nikhil Tandon, professor of endocrinology at the AIIMS. “But I don’t see any immediate clinical translation. We can’t use the current data to recommend routine CRP tests for diabetes.”
The conventional method of detecting pre-diabetes — which can emerge several years ahead of diabetes — involves a glucose tolerance test in which a person’s blood sugar is measured before and two hours after a drink of glucose-rich water.
The IGIB-AIIMS team examined CRP levels in 1,726 healthy volunteers, among whom 1,276 had normal glucose tolerance (NGT), 250 were found to have IFT and 200 had IGT. While the average CRP was 1.64mg/litre in volunteers with NGT, it was found to be 2.2mg/litre in persons with IFT and 2.32mg/litre in persons with IGT. This data supports the role of inflammation in pre-diabetes, the researchers wrote in their paper.
“This association was independent of other risk factors such as obesity, family history of diabetes, undesirable cholesterol levels, or blood pressure,” said Dwaipayan Bharadwaj, a senior biologist at the IGIB.
Studies suggest that the incidence of diabetes in India has increased from about 1 per cent in the early 1970s to 12 per cent in 2000. The detection of pre-diabetes may prompt people to exercise and alter diet in attempts to delay the onset of diabetes, Bharadwaj said.
Tandon, however, cautioned that the observed association between CRP levels and pre-diabetes does not establish a cause-and-effect relationship. “Causality cannot be inferred from this data,” he said.
For the moment, he said, the best available tests for pre-diabetes would be the glucose tolerance test. But the new findings call for further studies to determine the mechanisms through which inflammation might contribute to diabetes.
The IGIB-AIIMS team had shown last year that CRP levels are elevated in metabolic syndrome, a condition marked by high body mass index, high blood pressure, high cholesterol, and high blood sugar that increases the risk of cardiovascular disease.
“We find a clear dose relationship between CRP and metabolic syndrome,” Tandon said. “The CRP rises with the number of components of the metabolic syndrome in otherwise healthy persons.”
