People are relying on sleeping pills more than ever to get a good night's rest, but a new study by Scripps Clinic researchers links the medications to a 4.6 times higher risk of death and a significant increase in cancer cases among regular pill users. The results, published February 27 by the open-access online journal BMJ Open, cast a shadow over a growing segment of the pharmaceutical industry that expanded by 23 percent in the United States from 2006 to 2010 and generated about $2 billion in annual sales.

"What our study shows is that sleeping pills are hazardous（有危险的） to your health and might cause death by contributing to the occurrence of cancer, heart disease and other ailments（疾病） ," said author Daniel F. Kripke, MD, of the Viterbi Family Sleep Center at Scripps Health in San Diego.

The research is the first to show that eight of the most commonly used hypnotic（催眠的） drugs were associated with increased hazards of mortality and cancer, including the popularly prescribed medications zolpidem (known by the brand name Ambien) and temazepam (also known as Restoril), Dr. Kripke said. Those drugs had been thought to be safer than older hypnotics（催眠药） because of their shorter duration of action.

Study participants who took sleeping pills were matched with control patients of similar ages, gender and health who received no hypnotics in order to eliminate the possibility that other factors led to the results.

"We tried every practical strategy to make these associations go away, thinking that they could be due to use by people with more health problems, but no matter what we did the associations with higher mortality held," said co-author Robert D. Langer, MD, MPH, of the Jackson Hole Center for Preventive Medicine in Jackson, Wyoming.

Even among patients who were prescribed 1 to 18 sleeping pills per year, the risk of death was 3.6 times higher than among similar participants who did not take the medica-tions. The study looked at patients aged 18 years and older, and found the increased risk in all age groups.