Sleeping pills increase risk of death

28.02.2012

Doctors are calling for a rethink of the use of sleeping pills after a large study showed that the drugs carry a substantially increased risk of death for those who are prescribed them.

Commonly used sleeping pills, or "hypnotics", such as temazepam and zolpidem, which is prescribed for short-term insomnia, are associated with more than a fourfold risk of death, according to the study published in the BMJ Open journal.

The study was carried out in the US, where up to 10% of the adult population took sleeping pills in 2010. The authors estimate that sleeping pills may have been associated with 320,000 to 507,000 extra deaths in the US that year.

The researchers, led by Daniel Kripke from the Scripps Clinic Viterbi Family Sleep Centre in La Jolla, California, studied the population served by the largest rural integrated healthcare system in America, in Pennsylvania.

Over a two-and-a-half-year period, they compared the death rates among more than 10,500 people who received sleeping pill prescriptions with those of more than 23,600 others – matched for age, state of health and other factors – who had not received such medication. The average age of the study group was 54.

The scientists in the study found that even at a relatively low rate of prescription – fewer than 18 doses a year – those who were given the pills had a 3.5 times greater risk of death compared with those who were not prescribed them. Individuals who were given pills more frequently – between 18 and 132 doses in a year – were more than four times more likely to be dead at the end of the study. The risk of death for those on the most pills – 132 doses or more a year – was more than five times that of those on no pills.

Those who had taken the most pills were also 35% more likely to be diagnosed with cancer – although they had not been at greater risk of cancer than the control group before the study began. The risk was greatest for temazepam, one of the benzodiazepines. A link between sleeping pill use and cancer has also been found in previous studies.

Just showing an association between sleeping pills and more deaths does not prove the pills are the cause, the authors point out, although the increased risk as the number of doses went up points in that direction. But there have been other studies in the past that have also appeared to detect an increased death risk with sleeping pills, the authors say.

Some people taking the pills sleepwalk, which can be hazardous, and eat at night, "resulting in poor diet and obesity", says the paper.

In the study, people on sleeping pills were more likely to have oesophageal problems and peptic ulcers. They were more likely to be diagnosed with lymphomas, lung, colon and prostate cancers even than smokers.