Prescription drug use is rising across the United States. More people are taking medications and they're taking more of them.
A study published Tuesday by researchers at Harvard's T.H. Chan School of Public Health shows that 59 percent of adults used a prescription drug in a 30-day period. That's up from just 50 percent when the survey was last conducted a decade earlier.
The study also shows a rising number of people are taking multiple meds. The share of people who took more than five prescription drugs in a month nearly doubled to 15 percent.
"When we're starting to see more and more adults using five or more drugs, it does raise a concern about the potential for drug interaction," says Elizabeth Kantor, who is now an epidemiologist at Memorial Sloan Kettering Cancer Center in New York and the lead researcher on the study, which was published in JAMA, the journal of the American Medical Association.
Kantor says the increase in prescription use may be driven in part by the rise in obesity. That's because many of the widely used drugs treat conditions that can be related to obesity, such as diabetes, high blood pressure and high cholesterol.
"This might raise the question of how much of this increase in prescription drug use might be attributable to obesity, as we know that the prevalence of obesity has increased among adults in the United States," she says.
Kantor's team analyzed data from the National Health and Nutrition Examination Survey to compare prescription drug use in the years 1999-2000 and 2011-2012. In that survey, researchers interviewed people in their homes about which prescription medications they had taken in the previous 30 days. Interviewers asked the participants to show them the product medication's container.
The NHANES surveys each spanned two years and included nearly 40,000 people.
Another survey found that spending on medicines increased by 10.3 percent to $374 billion in 2014 from 2013, according to IMS Health, a Connecticut-based healthcare industry information company.
The Harvard study also shows increases in prescription use in areas including muscle relaxants and antidepressants.