Polycyclic aromatic hydrocarbons (PAHs) are formed during the incomplete burning of oil and gas, food, tobacco and other organic materials. Women with high PAH exposure, whether from diet or as a result of environmental factors, have been found to have higher breast cancer risk than those with low exposure. Now a new California study has reported that PAH may speed up breast development in girls.
Common sources of PAH exposure
The following are common sources of PAHs to which girls may routinely be exposed:
- Ambient air pollution (mostly from vehicular traffic)
- Grilled, barbecued, or fried meat or fish
- Smoked foods
- Synthetic firelog burning in indoor fireplaces
- Secondhand smoke.
PAH exposure due to these sources could be avoided or reduced in many cases.
Latest research finds PAH exposure accelerates breast development
The study referenced above was designed to investigate associations between PAH exposure and the timing of puberty. The study included a longitudinal cohort of girls aged six to 16 from the San Francisco Bay Area. Participant characteristics and sources of outdoor, indoor, and dietary PAH exposures were determined by questionnaire. The authors measured PAH-albumin adducts (a marker of PAH exposure formed when PAHs bind to albumin in the blood) in 215 baseline serum samples and 159 final or last samples. The samples were obtained between five and 69 months apart. PAH-albumin adducts were found in all but two of the samples.
The authors first calculated average PAH-albumin adduct levels according to participant characteristics and sources of PAH exposure, while adjusting for intra-familial correlations. The authors then estimated associations of adduct levels with recalled breast (sample size = 154) or pubic hair (153) Tanner Stage (a scale used to assess physical development during puberty) and menstruation status (116) at baseline. The authors also assessed associations with pubertal timing of girls who had not yet started breast (76) or pubic hair (86) development or menstruation (132) at first blood collection.
The authors defined lower PAH levels as below the median PAH adduct level and higher PAH levels as at or above the median. Girls with higher PAH levels were found to be more likely to have started breast development at baseline. The timing of breast development was the only pubertal outcome associated with PAH levels. In other words, higher PAH levels were found to be associated with earlier breast development, but not with earlier pubic hair appearance or first period. There were some variations in adduct levels by personal characteristics and sources of PAH exposure, but the differences did not reach statistical significance. The authors conclude that PAH exposure may cause earlier breast development in girls.
Please see our article on protecting our daughters from breast cancer and the PAHs tag for more information.