In utero BPA exposure linked to tots' behavior problems
Bisphenol A (BPA), an organic compound widely used in the manufacture of consumer plastics including food and beverage containers, may contribute to behavioral disorders in toddlers, especially girls, study findings indicate.
Increases in gestational urinary BPA concentrations were associated with behavioral disruptions among a cohort of 3 year olds (n=244) — for each ten-fold increase there was an adjusted increase in anxiety scores (β=7; 95% CI:1.7 to 12), Joe M. Braun, PhD, of the Harvard School of Public Health in Boston, and colleagues reported in Pediatrics.
This increase was more pronounced in girls (β=12, 95% CI 4.7 to 20) than boys (β=1.3, 95% CI −5.8 to 8.4), data indicate.
In addition to food packaging, BPA is used in products ranging from dental sealants to credit card receipts to medical equipment, making “exposure ubiquitous in industrialized and industrializing countries,” the researchers wrote.
Braun and colleagues are studying the compound's public health impact after data from animal studies indicate that BPA may have endocrine disrupting properties.
In previously published human studies, the group found a link between gestational BPA exposure and an increase in hyperactivity and aggression in 2-year-old girls. However, the extent to which these neurobehavioral changes persisted through development has remained uncertain.
To better understand the long-term effects of BPA exposure, Braun and collegues analyzed data from the Health Outcomes and Measures of the Environment Study, collecting maternal urine samples during the 16 and 26 weeks of pregnancy and children's urine samples on a yearly basis until age 3 years.
They evaluated behavior using the Behavior Assessment System for Children 2 (BASC-2) for subscales including anxiety, depression, aggression, hyperactivity and attention.
Executive functions such as emotional control, planning, memory and ability to inhibit behavioral responses and shift between tasks were assed using the Behavior Rating Inventory of Executive Function-Preschool (BRIEF-P).
After adjusting for confounding factors including maternal race, education, income, and marital status, as well as tobacco exposure, the researchers found that each tenfold increase in gestational urinary BPA resulted in higher depression scores, with the association most pronounced among girls:
- All children, β = 4 (95% CI 0 to 9.9)
- Girls, β = 11 (95% CI 3.6 to 18)
- Boys, β = −0.5 (95% CI −7.2 to 6.2)
Similar trends were noted in hyperactivity scores (girls, β=9.1, 95% CI 3.1 to 15; boys, β=−6.3, 95% CI −12 to −0.6) and emotional control (girls, β=9.1, 95% CI 2.8 to 15; boys) with increases observed among girls, but not boys.
"Gestational BPA exposures might affect endocrine or other neurotransmitter pathways and disrupt sexual differentiation of the brain, to alter behavior in a gender-dependent manner," the researchers wrote.
They recommended future research explore the way gender differences effect susceptibility based on varying levels of BPA exposure and phases of development.
In the meantime, clinicians may advise concerned parents to reduce exposure by “avoiding canned and packaged foods, receipts and polycarbonate bottles with the recycling symbol 7.”
However, the researchers cautioned that health consequences are still not fully understood and the benefits, if any, of limiting BPA exposure remain unknown.