Council on Environmental Health
Prepared by: Catherine J. Karr, MD, PhD
Baby Care Products: Possible Sources of Infant Phthalate Exposure
Sheela Sathyanarayana, Catherine J. Karr, MD, Paula Lozano, Elizabeth Brown, Antonia M. Calafat, Fan Liu, Shanna H. Swan.
Phthalates are synthetic chemicals found in a wide variety of personal care and other industrial products. They are anti-androgenic and have been associated with male genital tract abnormalities in animal studies. In humans, phthalate exposure in early childhood has been associated with altered hormone concentrations and an increased incidence of allergies and atopic disease. Sources of childhood phthalate exposure have not been well characterized.
The authors measured nine urinary phthalate metabolite concentrations in 163 infants (ages 2 – 28 months) whose mothers were originally recruited for the Study for Future Families, a multi-center pregnancy cohort study from 1999 – 2002. Mothers answered a questionnaire regarding products she or another person had used on the infant within 24 – 48 hours of the study visit when the urine was collected.
The distribution of phthalate concentrations in the infants was evaluated using multivariate linear regression to examine the relationship to reported product use. In order to examine exposures to multiple, combined phthalate metabolites, the authors used z-scores to standardize concentrations.
Urinary phthalate metabolite concentrations were widely variable in infant samples. Seven or more phthalate metabolites were above the limit of detection in approximately 80% of infant samples. Maternal report of exposure to baby lotion, baby shampoo, and baby powder was significantly predictive of increased urine phthalate concentrations for MEP (monoethyl phthalate), MIBP (monoisobutyl phthalate), and MMP (monomethyl phthalate) (p-value < 0.05). The z-score for combined MEP, MIBP, and MMP was significantly higher in infants exposed to baby powder, baby lotion, and baby shampoo compared to infants not exposed to these products, and the z-score for lotion use in an infant < 8 months old was 5.6 times that of an infant <8 months old who was not exposed. The z-score significantly increased in relation to the number of products used. The authors did not find significant relationships between urinary phthalate metabolite concentrations and report of pacifier, plastic toy, desitin/diaper cream, or baby wipe use.
This study was one of the first to document widespread phthalate exposure in a population of healthy infants. The study findings suggest that commonly used products such as lotion, shampoo, and powder may be sources of phthalate exposure for infants and that dermal absorption is the primary route of exposure. Of importance was the finding that these relationships were strongest in the youngest infants who may be the most vulnerable to toxicity given their immature metabolic system capabilities.
THE BOTTOM LINE
Phthalate toxicity is of increasing interest in the medical and public health community and the evidence base regarding the health risk is immature. Based on their findings, the authors recommend limiting the amount of infant care products used and not to apply lotions or powders unless indicated for a medical reason until more information is available.
PUBLIC HEALTH POLICY NOTE
In 2006, the European Union banned the use of 6 phthalate softeners in polyvinyl chloride toys designed to be placed in the mouth by children who are younger than 3 years. The ban covers 6 phthalates: DiNP, DEHP, DBP, di-isodecyl phthalate, DnOP, and butylbenzyl phthalate. California and Washington State have recently passed legislation regulating phthalate in products used by children.