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Key liver enzyme may predict gestational diabetes
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High levels of the liver enzyme gamma-glutamyl transferase, or GGT, an indicator of high oxidative stress, measured during early and middle pregnancy may predict the development of gestational diabetes, according to findings published in Clinical Endocrinology.
“Oxidative stress can induce free-radical activity and release lipid peroxidation products, which are thought to be involved in the development of insulin resistance,” Nianhong Yang, PhD, professor and director of the department of nutrition and food hygiene at Tongji Medical College, Huazhong University of Science and Technology in Hubei, China, and colleagues wrote. “This results in impaired insulin secretion from pancreatic beta cells. GGT is a key enzyme in gluthathione metabolism, which functions as an antioxidant process. Thus, GGT levels may be elevated in order to produce more gluthathione in response to oxidative stress.”
Yang and colleagues analyzed data from 1,512 pregnant women (88% Chinese Han descent) participating in the ongoing Tongji Maternal and Child Health Cohort, a prospective study examining the effects of diet on mothers and offspring. Mothers were recruited between September 2013 and September 2016. They provided fasting blood samples between 14 and 18 weeks’ gestation and underwent a 75-g 2-hour oral glucose tolerance test between 24 and 28 weeks’ gestation. Researchers assessed serum levels of GGT, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and used a linear regression model to analyze the correlation between liver enzyme levels during early pregnancy and glucose levels during late pregnancy.
Within the cohort, 8.1% of women developed gestational diabetes.
Researchers found that GGT levels were higher in women who went on to develop gestational diabetes when compared with women who did not develop gestational diabetes (mean, 18.7 U/L vs. 14.5 U/L; P < .001). There were no between-group differences for levels of ALT and AST.
In assessing sensitivity and specificity of GGT in predicting gestational diabetes, the optimum cutoff value determined by Youden’s index for GGT was 26.9 U/L, according to researchers, who then stratified the cohort into two groups (GGT levels 26.9 U/L and levels < 26.9 U/L).
In logistic regression analysis using the lower GGT range as the reference, women in the higher GGT range had a fivefold increased risk for gestational diabetes (RR = 5.81; 95% CI, 3.72-9.08), with results persisting after adjustments for age, parity, race, weight, prepregnancy BMI, family history of diabetes, fasting plasma glucose and gestational weight gain. RR remained high after further adjustment for factors that included BMI at time of liver enzyme test, education level, smoking status, alcohol intake and bilirubin levels (RR = 5.4; 95% CI, 3.36-8.68).
“GGT level of > 26.9 U/L may identify people with a higher risk for developing [gestational diabetes], although the value of GGT may be within a normal reference range based on the present clinical standard,” the researchers wrote. “Monitoring GGT levels in early to middle pregnancy may help to identify women with increased risk for developing [gestational diabetes].” – by Regina Schaffer
Disclosures: The authors report no relevant financial disclosures.
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