Exposure to the chemical bisphenol A (BPA), which can still be found in aluminum cans and several other consumer products, may be associated with an indicator for increased risk of kidney disease and future heart disease, according to a New York University School of Medicine study released today.

The study, published in the online issue of Kidney International, analyzed data from 710 U.S. children ages 6-19. The data was from the 2009-2010 National Health and Nutrition Examination Survey.

Researchers discovered that children with the highest amount of BPA in their urine had a significantly higher albumin-to-creatinine ratio than those with the lowest amount of urinary BPA.

Albumin is a protein that is not normally found in urine. The study suggests that even low levels of BPA in children increase oxidative stress and inflammation that contributes to the protein leakage into urine. Albumin in urine, the scientists said, is a potential early sign of kidney impairment and can lead to abnormalities in blood vessels and future risk of coronary heart disease, according to the study.

The Food and Drug Administration recently banned the use of BPA in baby bottles and sippy cups but allowed manufacturers to continue using the chemical in other food and beverage containers -- a position that has been heavily criticized by public health advocates. Manufacturers use BPA for its anti-corrosive and antiseptic properties.

The study "raises further concern about the FDA's decision not to ban BPA from other uses," said Leonardo Trasande, the study's co-author and associate professor of pediatrics, environmental medicine and population health at NYU.

"There are natural alternatives to the chemical," Trasande said.

The study controlled for a wide range of socio-demographic and environmental risk factors as well as insulin resistance, elevated cholesterol, weight and gender.

But some scientists suggested that Trasande's study may not be entirely representative of the general population.

"The biggest issue with cross-sectional national survey data studies like this is that the findings may be confounded by dietary practices such as drinking soda from cans or body composition," said Dana Dolinoy, an assistant professor in environmental health sciences at the University of Michigan. People with a higher fat mass may metabolize BPA differently from those with a lower fat mass, Dolinoy said.

Previous studies by Trasande's group showed a "significant association" between higher amounts of BPA in the urine of children and adolescents and obesity.

Additional research is necessary on BPA's effects in healthy children as well as in children with pre-existing kidney disease, said Howard Trachtman, co-lead author of the study. He expressed concern that children with less than fully functioning kidneys "may be more susceptible to the adverse effects of environmental toxins."

The American Chemistry Council questioned the study's methodologies. "Importantly, the study did not actually measure any effects on the heart or kidneys but only speculates about such effects," said Steven Hentges of the ACC's Polycarbonate/BPA Global Group.

The ACC also pointed to federal studies that found BPA to be safe. The studies found that, "because of the way BPA is processed in the body, it is very unlikely that BPA could cause health effects at any realistic exposure level. Furthermore, regulators from Europe to Japan to the U.S. have recently reviewed hundreds of studies on BPA and repeatedly supported the continued safe use of BPA," Hentges said.