Hair mercury levels, intake of omega-3 fatty acids and ovarian reserve among women attending a fertility center.

OBJECTIVE: To investigate the association of hair mercury (Hg) levels with antral follicle count (AFC), as a marker of ovarian reserve, and evaluate whether this relationship differed among women with high vs. low total intake of long chain omega-3 polyunsaturated fatty acids (n3PUFA) from foods and supplements. DESIGN: We included 353 women attending an academic fertility center (2007-2019) who had data on hair Hg levels, total n3PUFA intake, and AFC. METHODS: Hair Hg levels were assessed using a Direct Mercury Analyser, total n3PUFA intake was estimated using an extensively validated food frequency questionnaire, and AFC was assessed by transvaginal ultrasonography. Poisson regression models adjusted for potential confounders were used to evaluate the association of hair Hg levels (divided into tertiles, and as above vs below EPA reference (1 ppm)) with AFC. Associations were also evaluated after stratification by median n3PUFA intake (≤0.124% vs. >0.125% calories/week). RESULTS: Women's median hair Hg level was 0.60 ppm (range = 0.001-8.60 ppm), with more than 30% > 1 ppm (EPA reference level). Hair Hg was positively related to AFC after adjusting for age, BMI, smoking status, infertility diagnosis, and alcohol intake. However, associations became attenuated after adjustment for intake of total n3PUFA. The positive associations of hair Hg and AFC were observed only among women above the median total n3PUFA intake. Specifically, women who consumed >0.125% calories/week of total n3PUFA had mean AFCs of 11.9, 13.2 and 14.1, respectively, across increasing tertiles of hair Hg (p,trend = 0.004). Similar results were found when hair Hg was divided above vs below EPA reference (mean AFC = 12.7 vs. 14.1, p = 0.008). CONCLUSIONS: In these women, positive associations of hair Hg with AFC may be reflective of beneficial effects of n3PUFA on ovarian reserve rather than a beneficial effect of Hg per se. Our findings highlight the importance of considering diet when exploring Hg effects on women's reproductive health in urban settings.

Environmental exposure to metal mixtures and linear growth in healthy Ugandan children.

BACKGROUND: Stunting is an indicator of poor linear growth in children and is an important public health problem in many countries. Both nutritional deficits and toxic exposures can contribute to lower height-for-age Z-score (HAZ) and stunting (HAZ < -2). OBJECTIVES: In a community-based cross-sectional sample of 97 healthy children ages 6-59 months in Kampala, Uganda, we examined whether exposure to Pb, As, Cd, Se, or Zn were associated with HAZ individually or as a mixture. METHODS: Blood samples were analyzed for a mixture of metals, which represent both toxins and essential nutrients. The association between HAZ and metal exposure was tested using multivariable linear regression and Weighted Quantile Sum (WQS) regression, which uses mixtures of correlated exposures as a predictor. RESULTS: There were 22 stunted children in the sample, mean HAZ was -0.74 (SD = 1.84). Linear regression showed that Pb (ß = -0.80, p = 0.021) and Se (ß = 1.92, p = 0.005) were significantly associated with HAZ. The WQS models separated toxic elements with a presumed negative effect on HAZ (Pb, As, Cd) from essential nutrients with presumed positive effect on HAZ (Se and Zn). The toxic mixture was significantly associated with lower HAZ (ß = -0.47, p = 0.03), with 62% of the effect from Pb. The nutrient WQS index did not reach statistical significance (ß = -0.47, p = 0.16). DISCUSSION: Higher blood lead and lower blood selenium level were both associated with lower HAZ. The significant associations by linear regression were reinforced by the WQS models, although not all associations reached statistical significance. These findings suggest that healthy children in this neighborhood of Kampala, Uganda, who have a high burden of toxic exposures, may experience detrimental health effects associated with these exposures in an environment where exposure sources are not well characterized.

Maternal prenatal fish consumption and cognition in mid childhood: Mercury, fatty acids, and selenium.

BACKGROUND: Few studies of maternal prenatal fish intake have included biomarkers of exposure to mercury, long-chain n-3 fatty acids, and selenium, which are hypothesized to mediate associations with child neurodevelopment. OBJECTIVES: Examine associations of maternal prenatal fish intake with child neurodevelopment accounting for biomarkers. METHODS: In 1999-2002 we enrolled pregnant women into the Project Viva cohort. At median 27.9weeks gestation, we estimated maternal fish intake using food frequency questionnaires, and collected blood. We assayed erythrocytes for total mercury and selenium, and plasma for fatty acids including n-3 docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). In mid-childhood (median 7.7years), we administered cognitive tests including the Kauffman Brief Intelligence Test (KBIT). We performed multivariable linear regression analyses adjusting for maternal and child characteristics including home environment and maternal intelligence. RESULTS: Among 1068 pairs (872 with blood), mean (SD) exposures were: maternal fish intake 1.7 (1.5)servings/week, mercury 4.0 (3.6)ng/g, DHA+EPA 98.4 (41.8)mcg/ml, selenium 205.6 (34.6)ng/ml. Child KBIT verbal scores (mean 112.2, SD 15.0) were not related to any exposures: maternal fish intake (0.15; 95% CI: -0.50, 0.79), mercury (0.08; -0.18, 0.35), DHA+EPA (0.01; -0.22, 0.24), and selenium (0.20; -0.09, 0.50). Associations with KBIT nonverbal scores and tests of memory and visual motor abilities were similarly null. Mutual adjustment for each of the exposure measures did not substantially change estimates. CONCLUSIONS: In this population with an average fish consumption of about 1 1/2 weekly servings, we did not see any evidence for an association of maternal prenatal fish intake, or of mercury, DHA+EPA, or selenium status, with verbal or non-verbal intelligence, visual motor function, or visual memory at median 7.7years of age.

Lead in candy consumed and blood lead levels of children living in Mexico City.

BACKGROUND: Recent studies have shown that lead exposure continues to pose a health risk in Mexico. Children are a vulnerable population for lead effects and Mexican candy has been found to be a source of exposure in children. There are no previous studies that estimates lead concentrations in candy that children living in Mexico City consume and its association with their blood lead level. OBJECTIVES: To evaluate whether there is an association between reported recent consumption of candies identified to have lead, and blood lead levels among children in Mexico City. METHODS: A subsample of 171 children ages 2-6 years old, from the Early Life Exposure in Mexico to Environmental Toxicants (ELEMENT) cohort study was assessed between June 2006 and July 2007. The candy reported most frequently were analyzed for lead using ICP-MS. The total weekly intake of lead through the consumption of candy in the previous week was calculated. Capillary blood lead levels (BLL) were measured using LeadCare (anodic stripping voltammetry). RESULTS: Lead concentrations ≥0.1ppm, the FDA permitted level (range: 0.13-0.7ppm) were found in 6 samples out of 138 samples from 44 different brands of candy. Median BLL in children was 4.5µg/dl. After adjusting for child's sex, age, BMI, maternal education & occupation, milk consumption, sucking the candy wrapper, use of lead-glazed pottery, child exposure behavior, living near a lead exposure site and use of folk remedies, an increase of 1µg of lead ingested through candy per week was associated with 3% change (95% CI: 0.1%, 5.2%) in BLL. CONCLUSIONS: Although lead concentrations in candy were mostly below the FDA permitted level, high lead concentrations were detected in 4% of the candy samples and 12% of brands analyzed. Although candy intake was modestly associated with children's BLL, lead should not be found in consumer products, especially in candy that children can consume due to the well documented long-lasting effect of lead exposure.

Determination of in vitro bioaccessibility of Pb, As, Cd and Hg in selected traditional Indian medicines.

In vitro bioaccessibility of Pb, As, Cd and Hg in five traditional Indian medicine samples was measured as a determinant of bioavailability. The method is based on simulation of human digestion in the passage of material from the gastric to intestinal portions of the gastrointestinal tract. Total concentration and concentration in extracts from gastric and intestinal phases were analyzed for Pb, As and Cd by dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS) and for Hg by direct mercury analyzer (DMA). Total lead ranged from 1.9 to 36000 µg g(-1). In each of the samples bioaccessibility of lead was significantly higher (range 28-88%) in the gastric phase than in the intestinal phase (range 1.4-75.4%). Only Ekangvir Ras had measurable arsenic (304 µg g(-1)). Its bioaccessibility in the gastric phase and intestinal phase was 82.6% and 78.1%, respectively. Only Ayu-Nephro-Tone had measurable cadmium (14.4 µg g(-1)). Its bioaccessibility in the gastric phase and intestinal phase was 80.5% and 2.2%, respectively. Three samples had measurable mercury (range 37 µg g(-1)-10000 µg g(-1)). Mercury in these samples was not bioaccessible. For the samples with measurable amount of metal, the estimated daily amount of bioaccessible (EDAB) metal was calculated. When compared with the most liberal published safety guideline, EDAB-Pb in Mahayograj Guggulu and Ekangvir Ras were 37 and 45 fold greater. When compared with the most conservative published safety guideline, all samples had higher EDAB-Pb or EDAB-As than the suggested limits. The EDAB-Cd and EDAB-Hg were acceptably below published safety limits.

Three cases of lead toxicity associated with consumption of ayurvedic medicines.

Ayurveda is a traditional form of medicine used by majority of the Indians. Here we report three cases of lead toxicity, following intake of Ayurvedic medicines. Three patients presented with blood lead levels (BLLs) of 122.4, 115 and 42.8 µg/dl respectively at the time of hospitalization. The first case was chelated with D- penicillamine, the second with calcium disodium ethylene diamino tetra acetate (EDTA) and the third with environmental intervention and education. Associated Ayurvedic products were collected from patients and analyzed for metallic concentration. Cessation of Ayurvedic medication along with chelation, nutritional intervention and education, reduced the BLL to 27.4 µg/dl in the first case after 1 year, 21.1 µg/dl after 9 months in the second and 18.2 µg/dl after 6 months in the third case.

Influence of maternal bone lead burden and calcium intake on levels of lead in breast milk over the course of lactation.

The authors studied 367 women who were breastfeeding their infants in Mexico City, Mexico, between 1994 and 1995 to evaluate the effect of cumulative lead exposure, breastfeeding practices, and calcium intake on breast milk lead levels over the course of lactation. Maternal blood and breast milk lead levels were measured at 1, 4, and 7 months postpartum. Bone lead measurements were obtained at 1 month postpartum. At 1, 4, and 7 months postpartum, respectively, the mean breast milk lead levels were 1.4 (standard deviation (SD), 1.1), 1.2 (SD, 1.0), and 0.9 (SD, 0.8) microg/liter and showed a significant decreasing trend over the course of lactation (p < 0.00001). The relations of bone lead and blood lead to breast milk lead were modified by breastfeeding practice, with the highest breast milk lead levels among women with a high level of patella lead who were exclusively breastfeeding. Dietary calcium supplementation increased the rate of decline in breast milk lead by 5-10%, in comparison with a placebo, over the course of lactation, suggesting that calcium supplementation may constitute an important intervention strategy, albeit with a modest effect, for reducing lead in breast milk and thus the potential for exposure by infants.