Hormonal contraception and blood lead levels in inner-city adolescent girls

Association of blood lead with estradiol and sex hormone-binding globulin in 8-19-year-old children and adolescents

BACKGROUND

Metals can interfere with hormonal functioning through indirect mechanisms and by binding at the receptor site; thus, they may be associated with hormonal changes. However, there have been few studies on the health impact of metal exposure among children and adolescents. Thus, we aimed to examine the associations of blood lead level (BLL) with estradiol (E2) and sex hormone-binding globulin (SHBG) among children and adolescents aged 8-19 years in the National Health and Nutrition Examination Survey (NHANES) database.

METHODS

This was a cohort study of 2188 individuals from the NHANES. BLL was taken as independent variables, E2 and SHBG as dependent variable. We conducted weighted multivariate linear regression models and smooth curve fittings to evaluate the association between them.

RESULTS

The BLL was significantly positively associated with serum SHBG level in females, especially when the LnBLL quartiles are between Q3 and Q4. There was an inverted U-shaped association between BLL and E2 with the point of inflection at 1.86 μg/L and a U-shaped association between BLL and SHBG with the point of inflection at 1.86 μg/L in female adolescents aged 16-19 years. Meanwhile, In males, there was a positive trend of correlation between BLL and E2 in the 8-11 years, and 16-19 years groups.

CONCLUSIONS

This study found an inverted U-shaped association of BLL with E2 and a U-shaped association between BLL and SHBG in female adolescents aged 16-19 years. This indicates that adjusting blood lead exposure to mitigate the effects of lead on growth and development is important for adolescents aged 16-19 years. Controlling the BLL below 1.86 μg/L may minimize the damage to E2.

Depot Medroxyprogesterone Acetate Use and Blood Lead Levels in a Cohort of Young Women

BACKGROUND

Injectable contraceptive use is common, with 74 million users worldwide. Use of the injectable contraceptive depot medroxyprogesterone acetate (DMPA) is associated with bone mineral density loss. We hypothesize that increased bone resorption with DMPA use allows for mobilization of the toxic metal lead stored in bone to blood, presenting users with increased systemic exposure to lead.

OBJECTIVE

The objective of our study was to investigate the association between current DMPA use and blood lead concentrations.

METHODS

We conducted a cross-sectional analysis using enrollment data from the Study of Environment, Lifestyle & Fibroids (SELF), a cohort of 1,693 African-American women who were 23-35 years of age. Data on DMPA use were collected by computer-assisted telephone interview. Blood lead concentrations were measured in whole blood samples among 1,548 participants (91% of cohort). We estimated the adjusted percent difference in blood lead concentrations and 95% confidence intervals (CI) between current DMPA users and nonusers using multivariable linear regression.

RESULTS

Geometric mean blood lead concentration was 0.69 μ g / dL (95% CI: 0.67, 0.71). After adjustment, current DMPA users (7% of cohort) had blood lead concentrations that were 18% higher than those of nonusers (95% CI: 8%, 29%). Similar associations were observed with additional analyses to assess for potential bias from smoking, DMPA-induced amenorrhea, use of estrogen-containing contraceptives, having given birth in the prior year, and history of medical conditions or current medication use associated with bone loss.

DISCUSSION

Our results indicate that current DMPA use is associated with increased blood lead concentrations. Further research, particularly in populations highly exposed to lead, is warranted to consider tradeoffs between the adverse effects of lead on human health and the importance of DMPA as a contraceptive option to prevent unintended pregnancy. https://doi.org/10.1289/EHP7017.

Puberty and resultant increased bone turnover as a possible etiology of an increased lead concentration in a pre-adolescent girl

Introduction: We present a case in which puberty likely resulted in an increased lead concentration in a pre-adolescent girl.Case report: A 12-year-old girl was referred to the pediatric environmental health clinic (PEHC) after her blood lead level (BLL) was found to be elevated to 30 µg/dL (reference <5 µg/dL). She had been seen in the PEHC 6 years previously for management of a BLL as high as 36 µg/dL. Fifteen months prior to her repeat PEHC referral, her BLL had been 10 µg/dL. In those intervening 15 months, she grew 10.42 cm. Thyroid studies were normal. Four months after re-referral, her osteocalcin concentration, a marker of bone turnover, was 212 ng/mL (normal 9-42 ng/mL in adults >18 years); 10.5 months after the peak BLL of 32 mcg/dL, her BLL was 16 µg/dL, osteocalcin was 69 ng/mL, and her rate of growth had declined to 0.20 cm/30 days (peak: 1.07 cm/30 days). No external source of her exposure was found.Discussion: Osteocalcin concentrations and plotting the changes in growth velocity over time may assist clinicians in determining if pubertal growth is playing a role in unexpectedly increased BLL discovered in adolescents for whom no external source of lead exposure can be found.