Six in 10 American adults take Rx drugs. Here's what they're taking.

The percentage of American adults in recent years who took at least one prescription drug increased to nearly 60%, up eight percentage points from about a decade earlier, according to a study published Tuesday in JAMA.

Study details

For the study, researchers looked at 1999-2000 and 2011-2012 data from CDC's National Health and Nutrition Examination Survey. The data included responses from nearly 38,000 U.S. residents ages 20 or older about their prescription drug use within the 30 days prior to the survey.

According to the Washington Post's "To Your Health," the data for 2012 were the most recent data available.

Study findings

According to the study, 59% of American adults in 2011 and 2012 took at least one prescription drug, with 15% of such individuals taking five or more drugs. In comparison, 51% of U.S. residents in 1999 and 2000 took at least one prescription drug, with 8% of such individuals taking at least five prescription drugs during those years.

Further, the study noted an increase in the use of 11 out of 18 distinct classes of drugs that were found to be used by at least 2.5% of respondents. For instance, the study found that:

• Medications intended to treat high blood pressure were used by 27% of respondents in 2011-2012, up from 20% who used such treatments in 1999-2000;
• Statins and other cholesterol-lowering medications were used by 18% of respondents in 2011-2012, up from 8% who used such treatments in 1999-2000; and
• Antidepressants were used by 13% of respondents in 2011-2012, up from 7% of respondents who used such treatments in 1999-2000.

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Meanwhile, use of certain medications decreased between the two study periods. For example, the use of antibiotics decreased to 4.2% during 2011 to 2012, down from 5.7% in 1999 to 2000. And the use of sex hormones among women fell to 11% during 2011 to 2012, down from 19% in the earlier time period, in large part because of a drop in the use of hormones as a menopause treatment.

According to the study, older respondents were the most likely to report taking prescription drugs in 2011-2012, with about 90% taking at least one prescription drug and 39% taking at least five prescription drugs. In comparison:

• 65% of middle-aged respondents took at least one prescription drug during that time, with about 15% taking at least five; and
• 35% of respondents in their 20s and 30s took at least one prescription drug during that time, with about 3% taking at least five.

Meanwhile, the study found that non-Hispanic white U.S. residents took prescription drugs at about twice the rate of Hispanic Americans. The researchers did not indicate a reason for the difference but noted it "was not entirely attributable" to the groups' insurance rates.

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Reasons behind the increases

The researchers noted that obesity was likely a driver of the increase in prescription drug use. They found that among the 10 most-used drugs in the U.S., eight are treatments for diabetes, heart failure, hypertension, and other elements of "cardiometabolic syndrome."

Further, omeprazole, which is marketed under the name Prilosec, was also among the top 10 most-used drugs, and is used more commonly by those with above average weights.

However, Elizabeth Kantor, study co-author and an epidemiologist at Memorial Sloan Kettering Cancer Center, said, "There's so much going on in each area, it's hard to draw concrete conclusions," adding, "Each drug class stands on its own" (Reinberg, HealthDay/U.S. News & World Report, 11/3; Kaplan, Los Angeles Times/Sacramento Bee, 11/3; Dennis, "To Your Health," Washington Post, 11/3).