Puberty comes earlier for Girls, thanks to EDCs and Phthalates Exposure

Puberty comes earlier for girls, thanks to EDCs and phthalates… image via Mark Nockleby .

At the turn of the 20th century, the average age for an American girl to get her period was 16 to 17. Today, it is less than 13, according to national data. The trend has been attributed to the epidemic of overweight children and a greater exposure to pollution – the n° 1 factor that is pushing girls into puberty early seems to be their body mass index.

Among the toxins causing this trend, the biggest offenders are plastic compounds, in particular phthalates, man-made chemicals found all over the place: in plastic food and beverage containers, carpeting, shampoos, insect repellents, vinyl flooring, shower curtains, plastic toys and in the steering wheels and dashboards of most cars. Our bodies cannot metabolize phthalates, which interfere with the endocrine system—the body’s system of glands and hormones—and harm fat cells. Indirectly, phthalates may cause weight gain and so influence the timing of puberty…

Abstract

Background:
The observed age of menarche has fallen, which may have important adverse social and health consequences. Increased exposure to endocrine-disrupting compounds (EDCs) has been associated with adverse reproductive outcomes.

Objective:
Our objective was to assess the relationship between EDC exposure and the age of menarche in adolescent girls.

Methods:
We used data from female participants 12–16 years of age who had completed the reproductive health questionnaire and laboratory examination for the Centers for Disease Control and Prevention’s National Health and Nutrition Examination Survey (NHANES) for years 2003–2008 (2005–2008 for analyses of phthalates and parabens). Exposures were assessed based on creatinine-corrected natural log urine concentrations of selected environmental chemicals and metabolites found in at least 75% of samples in our study sample. We used Cox proportional hazards analysis in SAS 9.2 survey procedures to estimate associations after accounting for censored data among participants who had not reached menarche. We evaluated body mass index (BMI; kilograms per meter squared), family income-to-poverty ratio, race/ethnicity, mother’s smoking status during pregnancy, and birth weight as potential confounders.

Results:
The weighted mean age of menarche was 12.0 years of age. Among 440 girls with both reproductive health and laboratory data, after accounting for BMI and race/ethnicity, we found that 2, 5-dichlorophenol (2, 5-DCP) and summed environmental phenols (2, 5-DCP and 2, 4-DCP) were inversely associated with age of menarche [hazard ratios of 1.10; 95% confidence interval (CI): 1.01, 1.19 and 1.09; 95% CI: 1.01, 1.19, respectively]. Other exposures (total parabens, bisphenol A, triclosan, benzophenone-3, total phthalates, and 2, 4-DCP) were not significantly associated with age of menarche.

Conclusions:
Our findings suggest an association between 2, 5-DCP, a potential EDC, and earlier age of menarche in the general U.S. population.

Sources and more information

• Puberty Comes Earlier and Earlier for Girls, newsweek, January 26, 2015.
• Phthalate exposure and pubertal development in a longitudinal study of US girls, NCBI PMID: 24781428, pub 2014 Apr 29.
• Exposures to Endocrine-Disrupting Chemicals and Age of Menarche in Adolescent Girls in NHANES (2003–2008), Environ Health Perspect; DOI:10.1289/ehp.1104748 , 1 November 2012
• Preterm Birth, Fetal Growth, Age at Menarche among Women exposed prenatally to DiEthylStilbestrol, NCBI, 2010 Dec 2.
• Identifying Opportunities for Cancer Prevention During Pre-Adolescence and Adolescence: Puberty as a Window of Susceptibility, NCBI PMC4037133, May 28, 2014.