NEW YORK (Reuters Health) – As plasma levels of adiponectin, a protein produced by fat cells, rise, the risk of type 2 diabetes decreases, according to the results of a systematic review and meta-analysis reported in the Journal of the American Medical Association for July 8.

Obesity may affect the development of type 2 diabetes, at least in part, by altering adipokine secretion by adipose tissue, Dr. Rob M. van Dam, from Harvard Medical School, Boston, and colleagues note. Prior research has shown that greater adiposity reduces the secretion of adiponectin, an adipokine with both insulin-sensitizing and anti-inflammation properties.

Other studies have examined the link between adiponectin levels and diabetes risk, but the strength and consistency of the association was unclear, the authors note.

“To date, no systemic review has been conducted that evaluates the available evidence for an association between adiponectin levels and risk of type 2 diabetes across different populations,” they point out.

Searching MEDLINE, EMBASE, and Science Citation Index Expanded databases, the researchers identified 13 prospective studies that featured data on adiponectin levels and the development of type 2 diabetes. Included in the meta-analysis were 14,598 subjects and 2623 incident cases of type 2 diabetes.

For each 1-log microgram/mL rise in adiponectin levels, the risk of diabetes fell by 28%, the report indicates. This association was apparent in whites, East Asians, Asian Indians, African Americans, and Native Americans, the authors note, and it was not affected by the adiponectin assay used, method of diabetes case-finding, follow-up duration, or percentage of women.

In terms of the estimated absolute risk of diabetes, each 1-log micromol/mL increase in adiponectin levels gave rise to 3.9 and 30.8 cases per 1000 person-years for elderly Americans and Americans with impaired glucose tolerance, respectively.

“Adiponectin levels may be useful for identifying persons likely to benefit most from interventions to treat ‘dysfunctional adipose tissue’ and its metabolic complications,” the authors state. “Future studies should also evaluate whether adiponectin is useful for prediction of type 2 diabetes in addition to established risk factors using statistical techniques appropriate for prognostic analyses.”

Reference:
JAMA 2009;302:179-188.