Zinc, copper, and selenium concentrations associated with preterm birth
Researchers found high concentrations of the micronutrients selenium, copper, and zinc, in women who had preterm births, but they still do not know whether these high concentrations come from the food they eat.
Preterm birth occurs when a woman gives birth before she completes 37 weeks of pregnancy. Preterm birth is associated with negative health outcomes for the baby ranging from birth defects to death.
There can be many causes to preterm birth, but the role of high concentrations of micronutrients found in food and the environment is relatively unknown. These micronutrients are important for the development of the baby, but researchers want to know what happens when there is too much of them.
For this study, researchers aimed to measure the amounts of selenium, copper, and zinc in women who had preterm births, and then to determine the odds that preterm birth is caused by high amounts of each of the micronutrients studied.
The researchers collected blood samples from 181 women right after they gave birth at two hospitals in Lilongwe, the capital of Malawi, between June 2016 and March 2017. They shipped the blood samples to a laboratory in Norway where they extracted the serum, a purer form of blood, and measured the amounts of selenium, copper and zinc.
About half of the 181 women in the study had preterm births, and researchers found very high amounts of selenium, copper and zinc. They then adjusted their calculations to account for many other factors such as age, general health, and pregnancy history to tease out the suspected effects of the micronutrients in causing preterm birth.
They concluded that large amounts of selenium and copper did not play a significant role in causing preterm birth, but that high amounts of zinc increased the risk of preterm birth by over 6 times.
The large amounts of copper however was a concern for the researchers, because of the known toxic effects.
Having only 181 women participating in the study limited the researchers’ ability to properly find the risks associated with high levels of selenium, as a more suitable number of participants is 600. The daily diets of the participants were not investigated to find the possible sources of three micronutrients, and their Body Mass Index (BMI) was not recorded.
This is the first study of its kind measuring the effects of selenium, copper and zinc in pregnant women in Malawi. Africa has some of the highest levels of preterm births - over 18% compared to Western countries at 5%, so researchers want to know if nutrition plays a role.
Number of words: 402
Preterm birth is delivery before 37 completed weeks. A study was conducted to evaluate the association of maternal serum concentrations of selenium, copper, and zinc, and preterm birth. There were 181 women in this nested case-control study, 90/181 (49.7%) term and 91/181 (50.3%) preterm pregnant women. The overall mean serum concentration of selenium was 77.0; SD 19.4µg/L, copper was 2.50; SD 0.52 mg/L and zinc was 0.77; SD 0.20 mg/L with reference values of 47-142µg/L, 0.76-1.59mg/L and 0.59-1.11 mg/L, respectively. For preterm birth, mean serum concentrations for selenium was 79.7; SD 21.6µg/L, copper was 2.61; SD 0.57 mg/L, and zinc was 0.81; SD 0.20 mg/L compared to that of term births: selenium (74.2; SD 16.5µg/L; p=0.058), copper (2.39; SD 0.43 mg/L; p = 0.004), and zinc (0.73; SD 0.19 mg/L; p = 0.006) respectively. In adjusted analysis, every unit increase in maternal selenium concentrations gave increased odds of being a case OR 1.01 (95% CI: 0.99; 1.03), p=0.234, copper OR 1.62 (95% CI: 0.80; 3.32); p = 0.184, zinc OR 6.88 (95% CI: 1.25; 43.67); p=0.032. Results show that there was no deficiency of selenium, and zinc; and high serum concentrations of copper in pregnancy. Preterm birth was associated with higher maternal serum concentrations of copper and zinc.
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