Pregnant women with higher plasma concentrations of copper measured during the first trimester were more likely to have elevated glucose levels in the second trimester, increasing the risk for gestational diabetes, whereas higher concentrations of the trace metal molybdenum were associated with reduced glucose levels, according to findings published in The Journal of Clinical Endocrinology & Metabolism.
“Essential trace metal(loids) may be important to consider with respect to glucose intolerance in pregnancy, given their involvement in glucose homeostasis, and the potential to modify their levels through dietary management,” Yinnan Zheng, MS, a doctoral student in the department of environmental health at the Harvard T.H. Chan School of Public Health, and colleagues wrote in the study background. “Accumulating data from animal and metabolic studies demonstrated that a number of essential trace metal(loids), including zinc, selenium, chromium, iron, manganese, copper and molybdenum can impact glucose metabolism and insulin sensitivity with downstream effects on hyperglycemia and [gestational diabetes].”
Zheng and colleagues analyzed data from 1,857 healthy, normal-weight women from 12 U.S. clinical sites participating in the National Institute of Child Health and Human Development (NICHD) Fetal Growth Studies Singleton Cohort between July 2009 and January 2013. Researchers measured concentrations of zinc, selenium, copper and molybdenum in blood plasma samples collected during the first trimester of pregnancy (median, 12 weeks’ gestation). Primary outcome was blood glucose levels during the second trimester after a 1-hour 50 g gestational load test (median, 27 weeks’ gestation).
Among 264 women with an abnormal gestational load test, 58 women were diagnosed with gestational diabetes after an oral glucose tolerance test. An additional 76 women with a normal gestational load test also underwent an OGTT, with nine women diagnosed with gestational diabetes. Researchers found that levels of plasma zinc (median, 806 µg/L) and plasma selenium (median, 123 µg/L) were comparable to measurements among nonpregnant women measured in the National Health and Nutrition Examination Survey, whereas levels of copper (median, 1,874 µg/L) were higher vs. NHANES-measured levels.
In linear regression analyses, researchers found that higher concentrations of copper measured during the first trimester were associated with higher glucose levels measured during the second trimester, with each 50% increase in copper concentrations related to a 4.9 mg/dL higher glucose level measured via the gestational load test (95% CI, 2.2-7.5). Results persisted after adjustment for maternal sociodemographic characteristics and reproductive history.
In contrast, a 50% increase in molybdenum concentrations was associated with a 1.2 mg/dL lower mean glucose level measured via gestational load test (95% CI, –2.3 to –0.1).
For every 50% increase in copper concentration, women were 1.53 times more likely to have an abnormal gestational load test (95% CI, 1.19-1.97). For every 50% increase in molybdenum, women were 14% less likely to have an abnormal gestational load test (RR = 0.86; 95% CI, 0.78-0.96).
“If replicated and well quantified, these findings could provide early markers of potentially modifiable environmental exposures that are related to glucose dysregulation in pregnancy,” the researchers wrote. – by Regina Schaffer
Disclosures: The authors report no relevant financial disclosures.