Urinary nickel concentrations and selected pregnancy outcomes in delivering women and their newborns among arctic populations of Norway and Russia

Abstract

The two objectives of this study were to compare urinary nickel excretion in pregnant women and their newborns living in the Murmansk and Arkhangelsk Counties of Russia with that in comparable Norwegian populations living in Finnmark and the city of Bergen and to assess the influence on pregnancy outcome of different risk variables, specifically urinary nickel concentrations and questionnaire-based anamnestic information. Life-style information and urine samples were collected from 50 consecutive mother-infant pairs from hospital delivery departments in three Russian and three Norwegian communities. Pregnancy outcomes were verified from medical records. Urinary nickel excretion was significantly higher in the Russian communities, independent of the presence of a nickel refinery as a local environmental source. The birth weight and mean body mass index of the newborn children (BMIC) were significantly lower (p < 0.001) in the Russian groups, with or without adjustment for gestational age. A multivariate linear regression analysis indicated that maternal urinary nickel concentration had no impact on birth weight. The maternal body mass index (BMI) and maternal height were positive explanatory variables; maternal urinary creatinine is suggested as a weak negative factor. Smoking was shown to be a strong negative predictor only in the Norwegian group among whom there was a significantly higher smoking frequency (p = 0.005). The significant contribution of a country factor in the predictive model is interpreted to indicate that a number of important risk factors for low birth weight were not identified.

Elements in placenta and pregnancy outcome in arctic and subarctic areas

“…As pointed out in our previous papers (8)(9)(10), the mean birth weight of the Russian babies was significantly lower (p < 0.001), with or without adjustment for gestational age and gender. BMIC was also lower in Russia (p < 0.001), the babies were longer (p = 0.003) and the gestational age shorter (p < 0.001) (Table II).…”

“…The observed concentrations of essential and toxic elements in maternal serum (Cu, Zn, Se and Fe as ferritin), maternal whole blood (Cd, Ni, Pb, Se), cord blood (Cd, Pb, Se), maternal and neonatal urine (Ni and creatinine) and placental tissue (Cd, Cu, Fe, Ni, Pb, Se, Zn) have been published previously (1,(8)(9)(10)(11). A summary of the medians and ranges are provided in Table I.…”

“…Nickel exposure, as measured, by urinary nickel did not show any relationship to birth weight when we focused on the restricted cohort of pregnant women (and the neonate) for whom urinary nickel concentrations were available (8). Since placental nickel lost its statistical significance as a negative factor when examining gestational age-adjusted birth weight, the apparent association is likely related to the membership of this metal to the Factor 1 elements in the PCA (1,2).…”

“…Again P-Fe, P-Se and P-Zn make positive, but relatively small contributions (p > 0.05), with or without adjustment for gestational age. ORIGINAL RESEARCH Multivariate models to predict influences on birth weight and BMIC In our previous papers maternal age, number of deliveries, maternal weight, height and body mass index (BMI), and serum concentrations of the essential elements Fe (as ferritin), Se and Zn were found to be positively associated with birth weight, while maternal smo- ORIGINAL RESEARCH king frequency, maternal urinary creatinine, and MB-Pb have been found negatively associated (8)(9)(10). The only factor that significantly reduced the country factor was MB-Pb (10).…”

“…The objectives of this paper are to explore associations between the placental concentrations of the different elements to those in biological fluids reported previously by us (8)(9)(10) for the mother and corresponding neonate, as well as to the pregnancy outcomes of birth weight and child`s body mass index at birth (BMIC).…”