Our Stolen Futurea book by Theo Colborn, Dianne Dumanoski, and John Peterson Myers
 
 

 

Blanck, HM, M Marcus, PE Tolbert, C Rubin, AK Henderson, VS Hertzberg, RH Zhang and L Cameron. 2000. Age at menarche and Tanner stage in girls exposed in utero and postnatally to polybrominated biphenyl. Epidemiology 11:641-647.




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In 1973, more than 4000 people in Michigan were exposed to polybrominated biphenyls (PBBs) because of accidental food contamination. This study examines the impact of PBB exposure in the womb and after birth on the development of puberty in girls contaminated by the accident. Blanck et al. report that girls exposed to relatively high levels in the womb began menstruating up to a year earlier than those with lower levels. Perinatal exposure was also associated with earlier public hair development.

What did they do?
Blanck et al. contacted all girls (and/or their mothers) at least 5 yrs of age that had been born during or after the PBB incident whose mothers were participants in the Michigan PBB registry and invited them to participate in a study of pubertal development. Information was obtained from 327 girls. Serum measurements of PBB exposure had been obtained at the time of enrollment in the PBB registry (1976-1979). Six percent of participating mothers had breast milk PBB measurements. Mathematical models were used to estimate in utero exposure based on the serum and breast milk measurements. PCB measurements were also available for 85% of participants.

Study subjects (and/or mothers) were asked about various aspects of pubertal development, including age at menarche and standard assessments of breast and pubic hair development, as well as weight and recent physical activity. Mothers were also interviewed about their smoking and alcohol use during pregnancy.

What did they find.
The average estimated PBB exposure in the womb was 17.3 parts per billion, while average in utero PCB exposure was 5.6 ppb.

At the time of the study, 64% of the girls had reached menarche. Their average age at menarche was 12.3 yrs.

"Breastfed girls exposed to high levels of PBB in utero (at least 7 ppb) had an earlier age at menarche than breastfed girls exposed to lower levels." Ages at menarche for these two groups were 11.6 yrs and 12.2-12.6 yrs, respectively. Girls not breast fed had a slightly higher age at menarche (12.7 yrs). It would appear that the additional exposure through breast-feeding added to the impact of in utero exposure, that is the strongest impact (youngest age at menarche) was seen among girls with higher in utero exposure who also were exposed through breastfeeding.

PCB exposure showed no association with age at menarche.

Breast development: The data were inconclusive. "There was a suggestion of earlier breast development for breastfed girls with moderate in utero PBB exposure, but not for breastfed girls with high exposure."

Pubic hair development: Breast-fed girls with higher PBB in utero exposures showed pubic hair development earlier than breastfed girls with lower exposures.

In conclusion, Blanck et al. note "The associations observed here lend support to the hypothesis that pubertal events may be affected by perinatal exposure to organohalogens."

 

 

 

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