Blood lead and cadmium levels in a six hospital employee population. PESA study, 2009.

INTRODUCTION: Exposure to lead and cadmium is a public health problem due to the broad exposure to these toxic substances among the general population. The objective of this study is to determine blood lead and cadmium concentrations in a working population drawn from six university hospitals in Madrid, Getafe, Cartagena, Santiago de Compostela, Santander and Palma de Mallorca (Spain) and to identify associated factors. MATERIALS AND METHODS: 951 individuals participated in the study and were administered the standardized PESA® questionnaire regarding exposure to lead and cadmium. The blood lead and cadmium concentrations were measured by electrothermal atomization atomic absorption spectrometry with Zeeman background correction in Perkin-Elmer spectrometers, guaranteeing the transferability of the results. RESULTS: The median overall blood lead concentration was: 1.6 µg/dL (IQR: 0.9-2.7) and that of cadmium was: 0.21 µg/L (IQR: 0.10-0.50). There were significant differences in lead levels between men (2 µg/dL) and women (1.5 µg/dL), postmenopausal (2.6 µg/dL) and premenopausal women (1.1 µg/dL), and between participants who cooked in earthenware (2.1 µg/dL) and those who did not (1.5 µg/dL). The median of cadmium in women (0.24 µg/L) was higher than in men (0.11 µg/L) and was also higher in subjects who smoked (0.70 µg/L) than in non-smokers (0.13 µg/L). CONCLUSIONS: A reduction in blood lead and cadmium levels was observed with respect to previous studies carried out in Spain. Nevertheless, the results suggest there are certain factors which increase risk such as age, gender, menopause, age of housing, cooking in lead-glazed earthenware and exposure to cigarette smoke.

Oxidative stress in mothers who have conceived fetus with neural tube defects: the role of aminothiols and selenium.

BACKGROUND & AIMS: Methionine metabolic impairment and selenium deficit have been associated to neural tube defects. The relationship between thiol metabolism and selenium is not well known. We assessed the status of aminothiols and selenium, as well as thiolic status and the amino acids involved in arginine synthesis in the case of selenium depletion and repletion, studying their relationship to neural tube defects. METHODS: We studied 44 women of 37 +/- 8 years (mean +/- SD) who had conceived fetuses with neural tube defects as cases; and 181 women of 39 +/- 7 years (mean +/- SD) with healthy children as controls. We determined selenium, vitamin B12, serum folates, plasma thiol compounds and amino acids. Homocysteine transsulfuration was assessed using total cysteine/total homocysteine ratio (tCys/tHcy), and selenium repletion cut-off value was 1.06 micromol/l (84 microg/l). RESULTS: Cases showed significantly lower levels (median) than controls of total homocysteine (P = 0.001), total cysteinylglycine (P < 0.001), selenium (P < 0.001) and tryptophane (P = 0.002); and higher tCys/tHcy levels (P < 0.001), glutathione (P = 0.008) and L-arginine (P = 0.001). Cases with selenium depletion (selenium < or = 1.06 micromol/l) had significantly higher levels than controls of cysteine (P = 0.010), glutathione (P = 0.005), tCys/tHcy (P < 0.001), and arginine (P = 0.004), but significantly lower levels than controls of tryptophane (P = 0.027), cysteinylglycine (P < 0.001) and folates (P < 0.001). Only cysteinylglycine was lower than controls (P < 0.001) when selenium > 1.06 micromol/l. Methionine levels were higher in cases with selenium depletion than in repletion (P = 0.029). CONCLUSIONS: According to our data, a diet deficient in selenium and folates or their absorption impairment, and/or other mechanisms related to polyamines and nitric oxide can lead to oxidant/antioxidant imbalance and to a higher occurrence of these malformations.

Folate status and a new repletion cut-off value in a group of healthy Majorcan women.

BACKGROUND AND AIMS: Folate status is complex, complicated to assess and we lack consensus for laboratory determination. Total plasma homocysteine (Hcy) is a sensitive marker of folate status. The aim of this study was choosing a plasma total homocysteine (tHcy) measurement method and folate repletion level; assess the mutation C677T frequency for methylenetetrahydrofolate reductase (MTHFR) and the prevalence of hyperhomocysteinemia in healthy Majorcan women. METHODS: The measurement methods were compared using 219 women. Folate status assessment was determined by plasma tHcy, serum and erythrocyte folate and C677T for MTHFR in 342 healthy women. The mutation frequency is established with 146 of them. RESULTS: The measurement method comparison is summarized by Y = 1.013 (IC 95% 0.959, 1.069) X +0.829 (IC 95% 0.485, 1.170). The folate repletion level was set at Hcy < or = 8.6 micromol/l. Women (67.1%) are heterozygotic and do not carry the mutation. Homozygotic frequency is 18.5%, significantly higher in women under 40 years (P = 0.033). Hyperhomocysteinemia prevalence is 19.3%, and 51.7% in the younger group. CONCLUSIONS: Hcy determination by polarized fluorescence immunoassay reflects folate status. Levels < or = 8.6 micromol/l suggest folate repletion, which is less frequent in homozygotes. Population frequency for homozygotic-TT alleles for C677T-MTHFR reductase and hyperhomocysteinemia is significantly higher in women under 40 years.