Chronic pain affected about 20% of U.S. adults in 2016 and high-impact chronic pain — severe enough to interfere with life or work activities most days — affected 8%, according to the CDC.

That translates to 50 million people with chronic pain and about 20 million people with high-impact chronic pain, reported James Dahlhamer, PhD, of the CDC’s Division of Health Interview Statistics in Hyattsville, Maryland, and colleagues in Morbidity and Mortality Weekly Report.

This is the first-ever CDC assessment of high-impact chronic pain. Population-based estimates of chronic pain among American have ranged from 11% to 40%, with considerable variance among different segments of the population.

Chronic pain contributes to an estimated $560 billion each year in direct medical costs, lost productivity, and disability programs. In 2016, the National Pain Strategy, the first national population health-level plan for pain prevention, treatment, and management, called for more precise estimates to establish the prevalence of chronic pain and guide population-wide pain interventions.

In response, CDC researchers analyzed data from 33,028 adults in the 2016 National Health Interview Survey, a cross-sectional, in-person, household poll. They defined chronic pain as pain on most days or every day in the past 6 months, and high-impact chronic pain as chronic pain that limited life or work activities on most days or every day during the past 6 months.

The analysis showed that in 2016, an estimated 20.4% of U.S. adults (50 million) had chronic pain and 8.0% (19.6 million) had high-impact chronic pain, with rising prevalence tied to advancing age.

The age-adjusted prevalence of both chronic pain and high-impact chronic pain was significantly higher among women, and among adults who had worked previously but were not currently employed, adults living in or near poverty, and rural residents. It was significantly lower among people with at least a bachelor’s degree compared with other education levels.

This analysis is limited by self-reported data which may be subject to recall bias, the researchers noted. The data are cross-sectional, so causal inferences cannot be made. This may be especially important for socioeconomic status, which can be both a risk factor for, and a consequence of, chronic pain.

Dahlhamer reported no conflicts. Other authors reported relationships with Pain Medicine journal, Pfizer, and inVentive.