Reuters Health Information (2011-10-26): Low glycated hemoglobin linked with liver disease
Low glycated hemoglobin linked with liver disease
Last Updated: 2011-10-26 15:00:26 -0400 (Reuters Health)
NEW YORK (Reuters Health) - Low levels of glycated hemoglobin (HbA1c) may be associated with certain markers of liver dysfunction, a new study shows.
"Low HbA1c may be a general marker of poor health, analogous to low cholesterol levels," the researchers say -- although the lead author of the study told Reuters Health it's too soon to say everyone with a low HbA1c level should be screened for liver disease.
In a population-based study the research team found J-shaped associations between HbA1c and elevated levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and hepatic steatosis.
Compared with HbA1c levels between 5.0% and 5.5%, a level below 4.0% was linked with a 3.62-fold increased risk of ALT elevations and a 6.8-fold increased risk for AST elevations, according to a report in the September 27th online issue of Diabetes Care.
Levels below 4% were also associated with higher risks for abnormal gamma glutamyltransferase (GGT) and hepatic steatosis, but these associations were not statistically significant.
After excluding patients with anemia, iron overload, or hepatitis B or C, the associations were no longer significant.
Similarly, HbA1c below the 1st percentile was associated with significantly increased risks for high ALT (3.18-fold) and AST (5.80-fold), but not for elevated GGT or hepatic steatosis.
"With the new recommendations by the American Diabetes Association and World Health Organization for the use of HbA1c for the screening and diagnosis of diabetes, physicians may encounter low HbA1c values more often than before," said lead author Andrea L. Christman from Johns Hopkins University, Baltimore, Maryland in an email to Reuters Health.
"Our study suggests that low HbA1c test results may reflect other underlying health conditions, possibly liver disease," she said.
Her group's conclusions are drawn from data on 12,533 participants in the Third National Health and Nutrition Examination Survey (NHANES III 1988-1994) without self-reported diabetes.
"We did not observe an association between low fasting glucose and liver disease," the researchers note, "suggesting that the association with low HbA1c may be independent of glycemic pathways."
"It is premature to recommend routine screening for liver disease in the setting of low HbA1c," Christman said. "Additional studies to understand health implications of very low HbA1c are warranted. In particular, including HbA1c testing in studies of liver disease will be important."
"Physicians should be aware that conditions exist (e.g., anemia, iron overload) that may interfere with HbA1c interpretation," Christman added. "Using repeat testing by different methods and/or testing fasting glucose can be helpful to rule out laboratory error and many interfering conditions."
Diabetes Care 2011.