Bisphenol A, the chemical commonly known as BPA, and found in everything from water bottles to food-can liners, may be linked to decreased sperm quality in men, according to a new study from the University of Michigan.

Scientists and consumer advocates have questioned the safety of the highly controversial chemical, which is used to make plastic bottles, plastic dinnerware, CDs, the lining of food cans and even store receipts.

Animal studies have suggested reproductive health consequences from BPA, but there have been limited human studies, said lead author John Meeker, assistant professor of Environmental Health Sciences at U-M's School of Public Health.

At an infertility clinic in the Boston area, researchers collected urine and sperm samples from 190 men.

About nine in 10 of the men had levels of BPA in their urine, consistent with U.S. Centers for Disease Control and Prevention data on population exposure to the chemical, Meeker said.

Those who had the highest urinary concentrations of BPA had a 23 percent decline in sperm concentration and a 10 percent increase in sperm DNA damage, according to the study.

It is not clear what that link might have at an individual level, but when looking at how many couples struggle with infertility at the population area, it could be signifcant, Meeker said.

But, Meeker was quick to point out, more study will need to be done to draw stronger conclusions by taking larger sample sizes and more precise measurements. There are limitations to the study because it has to be observational, or conducted simply by taking samples to look for links between exposure levels and markers of sperm health - and not by actually controlling doses of BPA expsoure.

It is an important step, though, in examining the impact the chemical might have throughout the life span, Meeker said.

"Much of the focus for BPA is on the exposures in utero or in early life, which is of course extremely important, but this suggests exposure may also be a concern for adults," Meeker said in a statement. "Research should focus on impacts of exposure throughout multiple life stages."

Meeker conducted the study with Russ Hauser, the Frank Lee Hisaw Professor of Reproductive Physiology at Harvard School of Public Health and with assistance from colleagues at Massachusetts General Hospital and the U.S. Centers for Disease Control and Prevention.

The study is ongoing and researchers are looking to recruit hundreds of more men to further examine the link between BPA and sperm quality, Meeker said.

According to the CDC, BPA has been found to affect reproductive systems in laboratory animals, but more research is needed to understand the impact it can have on humans.

In a January report, the U.S. Food and Drug Administration said it shared some concern with the National Toxicology Program at the National Institutes of Health "about the potential effects of BPA on the brain, behavior, and prostate gland in fetuses, infants, and young children." It said it was moving to clarify uncertainties about the risks of BPA and supporting a shift to a more robust regulatory framework for oversight of BPA.

Tina Reed covers health and the environment for AnnArbor.com. You can reach her at tinareed@annarbor.com, call her at 734-623-2535 or find her on Twitter @TreedinAA.