Perfluorinated chemicals studied in breast milk, menopausal women.
Mondal D, RH Weldon, BG Armstrong, LJ Gibson, MJ Lopez-Espinosa, HM Shin, T Fletcher. Breastfeeding: A potential excretion route for mothers and implications for infant exposure to perfluoroalkyl acids. Environmental Health Perspectives. 2013. http://ehp.niehs.nih.gov/1306613/.
Taylor KW, K Hoffman, KA Thayer, JL Daniels. Perfluoroalkyl chemicals and menopause among women 20-65 years of age (NHANES). Environmental Health Perspectives. 2013. http://ehp.niehs.nih.gov/1306707/.
Researchers have for the first time quantified an association between breastfeeding and perfluorinated compounds in infants. In the study, the longer the women nursed their babies, the higher the levels of certain chemicals in their babies’ blood.
While other studies have documented the presence of PFCs – used to make non-stick cookware and stain-resistant materials – in breast milk, few have examined the rate at which these chemicals pass from mother to infant.
The scientists, led by researchers at the London School of Hygiene and Tropical Medicine, said that women should not stop nursing their babies because the levels were “very low.”
“While breastfeeding can be an important excretion route for lactating mothers and exposure route for nursing infants, for most people, levels are very low and it is important to note that breast milk remains the optimal food for infants,” wrote the authors in the study published online in the journal Environmental Health Perspectives.
Blood was collected from 633 women with a child younger than 3.5 years and from 49 – roughly 8 percent – of the infants. The women participated in the C8 Health Project, a study undertaken to investigate health impacts of contaminated drinking water near a DuPont factory in West Virginia.
The researchers determined that each month of breastfeeding was associated with a 3 percent decrease in mothers’ blood levels of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) and a 2 percent decrease in perfluorononanoic acid (PFNA). Study women breastfed for an average of 3.5 months.
Infant PFOA levels were 6 percent higher while PFOS levels were 4 percent higher for each month of breastfeeding.
The researchers could not rule out that the decline in the women’s levels was due to them avoiding food and drink sources with higher levels of contaminants. Levels of PFCs of women in the cohort have been dropping since 2005-2006, when the study was conducted.
PFCs can disrupt hormones but the potential health effects on infants are unknown. Previous studies from the C8 Health Project found no probable link between fetal and early postnatal PFOA exposure and birth defects or neurodevelopmental disorders in children.
Another new study by other scientists adds to the growing body of research suggesting a link between PFC exposure and early menopause.
Researchers analyzed data on PFC levels and menopausal status for 2,732 women between the ages of 20 and 65 in a nationwide sample.
After the scientists adjusted for age and other factors, "women with higher levels of PFCs had earlier menopause compared to women with the lowest levels," says the study published online in Environmental Health Perspectives. Included were PFOA as well as two compounds, PFNA and perfluorohexane sulfonic acid (PFHxS), which had not previously been studied in relation to menopause.
"The consistency and robustness of our findings suggest that there is a relationship between PFCs and menopause, though the underlying mechanism of that association remains unknown," wrote the scientists from the National Institute of Environmental Health Sciences and the University of North Carolina.
However, it remains unclear whether PFCs may contribute to earlier menopause or whether menopause may contribute to higher levels of PFCs. The compounds may be eliminated from the body during menstruation, the researchers said.
Early menopause is associated with health impacts, including a higher risk of heart disease and stroke. The average age of natural menopause in the women was 49.
PFC levels also were associated with hysterectomy in the study. Women with the highest levels of PFHxS were 3.5 times more likely to have had a hysterectomy than women with the lowest levels. Women with higher levels of PFOA and PFOS were also slightly more likely to have had a hysterectomy.
Previous research found that high levels of PFOA in drinking water were associated with delayed onset of puberty in girls and earlier menopause.