"Previous studies examining gastric reflux and cancers of the head and neck have generated mixed results," said Scott M. Langevin, Ph.D., postdoctoral research fellow at Brown University in Providence, R.I. "Most of those studies had either few numbers of cases or they were not adjusted for confounding factors. Ours is a large, population-based study with robust parameters that strongly suggests gastric reflux, which causes frequent heartburn, is an independent risk factor for cancers of the pharynx (throat) and larynx (vocal cord)."

Langevin and his colleagues identified 631 patients from a large group of individuals enrolled in a population-based, case-control study in the greater Boston area. Of the 631 participants, 468 had throat cancer and 163 had cancers of the vocal cord. An additional 1,234 individuals matched for age and gender with no prior history of cancer were recruited using town records to serve as controls for the study.

All participants completed a questionnaire on their history of heartburn, smoking and drinking habits, family history of cancer and sociodemographic information. Because some head and neck cancers are caused by infection with human papillomavirus 16 (HPV 16), the researchers tested for the presence of antigens to HPV 16 viral proteins in the blood of all participants.

Langevin and his colleagues found that among participants who were neither heavy smokers nor heavy drinkers, a history of frequent heartburn was linked to a 78 percent increased risk for cancers of the throat and vocal cord. They also found that among those who had frequent heartburn, taking antacids, but not prescription medications or home remedies, had a protective effect, with a 41 percent reduced risk for cancers of the throat and vocal cord. The protective effect of antacids was consistent, irrespective of the participants' smoking or drinking status, HPV 16 status or tumor site.

"Additional studies are needed to validate the chemopreventive effects of antacids among patients with frequent heartburn," said Langevin. "The identification of gastric reflux as a risk factor for throat and vocal cord cancers, however, may have implications in terms of risk stratification and identification of high-risk patients."