Iodine nutrition among pregnant women in B.M.C
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Iodine is an essential nutrient for thyroid hormone production. Due to inadequate public health measures, mild-moderate iodine deficiency has become a re-emerging problem in many developed countries in the past decades. Insufficient consumption of iodine in pregnancy may lead to brain damage and a lower Intelligence Quotient (IQ) in children in comparison to children of mothers with adequate intake. Recent National Health and Nutrition Examination Surveys (NHANES) data have shown that even though the non-pregnant United States (U.S) population has adequate iodine intake, U.S pregnant women are currently mildly iodine deficient, with median urinary iodine concentrations (UIC) being 129 μg/L. In 2004 pregnant women who attended the Boston Medical Center (BMC) Antenatal Clinic were also mildly iodine deficient, with median UIC of 149 μg/L. These values were higher than the NHANES median UIC (129 μg/L) Due to national trends of mild-moderate iodine deficiency among pregnant women, and since in 2011 the American Thyroid Association recommended that prenatal vitamins contain 150 μg of iodine, in this study we aimed to determine if the iodine status among the BMC pregnant women has changed. We also aimed to assess consumption of iodine-containing foods, knowledge regarding iodine nutrition, and frequency of use of iodine-containing prenatal vitamins. We conducted a cross-sectional study targeting 125 women living in the Boston area attending the BMC Antenatal Clinic. To date, 61 women have been enrolled. Participants provided urine samples, and completed questionnaires about their recent food intake and demographic characteristics. The participants’ mean age was 31 ± 6.7 years and their median UIC was 145.5 μg/L (range 17.5 μg/L- 886 μg/L). As expected, UIC was positively associated with iodine supplement intake and recent consumption of iodine-rich foods (milk cheese) (p< 0.0001 for each), although these associations were not significant in multivariate analysis. No associations were observed between UIC and other factors such as age, race, education, use of multivitamins containing iodine in the past 24 hours, and whether health providers discussed iodine nutrition, possibly due to a small sample size. Our results indicated that the iodine status of pregnant women attending B.M.C remained mildly iodine deficient in the past decade despite the recommended measures to increase the iodine content in multivitamins. In our sample, 52.5% of the pregnant women who attended BMC were mildly iodine deficient with median UIC <150 μg/L. Thus half of the pregnant women are at risk of brain damage occurring to their infant. It is important that follow up studies are done to determine the neurodevelopment of these children, as they grow older. Also since the intake of multivitamins containing iodine and consumption of dairy foods was positively associated with higher UIC levels, further measures need to be undertaken to ensure that all prenatal vitamins have 150 μg of iodine, and that pregnant women have higher dairy consumption, in order to increase their iodine intake. As well, larger regional and national studies should be undertaken to better understand current iodine status and sources of iodine among pregnant women.