title: Interdependence between urinary cobalt concentrations and hemoglobin levels in pregnant women.
abstract: Cobalt is an essential trace element but may cause toxic effects upon occupational or environmental exposure. Women accumulate more cobalt than men at similar exposure levels which may be related to higher metabolic iron loss. During pregnancy these losses are much stronger but their influence on cobalt intake has not been studied. We have studied the associations between changes in hemoglobin and cobalt urinary excretion during pregnancy. 391 pairs of urine and blood samples from pregnant women were collected during the 12th and 32nd weeks of pregnancy and were analyzed for cobalt and hemoglobin. Mean concentrations of urinary cobalt were 0.73 and 1.6 µg/g creatinine during the first and third trimesters, respectively (p<0.001). 84% of pregnant women had higher levels of cobalt in the third than in the first trimester. Cobalt concentrations were negatively associated to hemoglobin levels in the third trimester (p<0.05). Women with higher iron decreases between both trimesters had significant cobalt increases between these two periods. This correspondence involved a statistically significant difference in third trimester mean cobalt concentrations of anemic and non-anemic women, 1.8 and 1.5 µg/g creatinine, respectively (p<0.05). No significant differences between these two groups were found during the first trimester. These results were used to construct generalized additive models both in normal and anemic women. The strong association between the changes of both iron status and cobalt urine levels found in pregnant women may be related to higher intestinal absorption of cobalt at iron depletion such as in the last pregnancy period when iron body demands are high. Possible toxicity effects of these cobalt increases along pregnancy should be considered in cases of populations occupationally or environmentally exposed to this metal.
authors.affiliation: Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona, 18, 08034 Barcelona, Catalonia, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Fort
authors.affiliation: Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona, 18, 08034 Barcelona, Catalonia, Spain. Electronic address: joan.grimalt@idaea.csic.es.
authors.forename: Joan O
authors.initials: JO
authors.lastname: Grimalt
authors.affiliation: Center of Research in Environmental Epidemiology (CREAL), Doctor Aiguader, 88, 08003 Barcelona, Catalonia, Spain.
authors.forename: Maribel
authors.initials: M
authors.lastname: Casas
authors.affiliation: Center of Research in Environmental Epidemiology (CREAL), Doctor Aiguader, 88, 08003 Barcelona, Catalonia, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Sunyer
mesh_terms: D003035:Cobalt / Q000652:urine*; D005260:Female; D006456:Hemoglobinuria / Q000652:urine*; D006801:Humans; D011247:Pregnancy
chemical_list: D003035:Cobalt
keywords: Anemia; Changes in iron and cobalt during pregnancy; Cobalt; Hemoglobin; Pregnant women; Urine analyzes