People who have chronic widespread pain die earlier than those without chronic pain, reported new research from the United Kingdom, and lifestyle may play a significant role in their mortality.
Chronic widespread pain patients who participated in UK Biobank — a cohort of 500,000 people ages 40 to 69 recruited throughout Great Britain — had a mortality risk ratio (MRR) of 2.43 (95% CI 2.17-2.72), according to Gary J. Macfarlane, MD, PhD, of the University of Aberdeen, and colleagues. This excess risk was substantially reduced after adjusting for low levels of physical activity, high body mass index (BMI), poor quality diet, and smoking.
“The evidence is now clear that persons with chronic widespread pain experience excess mortality,” the researchers wrote in Annals of the Rheumatic Diseases. “UK Biobank results considerably reduce uncertainty around the magnitude of excess risk, and demonstrate that the risk is unlikely to be due to the experience of pain per se, but is substantially explained by lifestyle factors associated with having pain (poor diet, low levels of physical activity, smoking, higher BMI).”
It’s the largest study to examine the relationship between chronic widespread pain and mortality, the authors indicated, and has considerably more detailed information about potential mediators of any excess risk associated with widespread pain and death.
UK Biobank included 7,130 participants who reported “pain all over the body” for more than 3 months, and 281,718 people who did not have chronic pain. These two sub-cohorts represented the study population for the current analysis. Both groups had the same median age (58 years), but the chronic pain group was less likely to be male (36.3% versus 50%) and more likely to be heavier than normal weight (80.4% versus 63.5%). They also were twice as likely to be a current smoker (18.6% versus 9.3%) and were less physically active. Participants in UK Biobank were recruited throughout Great Britain from 2006 to 2010; information about deaths in this group was available through mid-2015.
The researchers found that, after adjusting for age and sex and excluding deaths that occurred in the first two years, participants with chronic widespread pain had a more than twofold risk of dying in the follow-up period. Adjusting for age and sex, they found that excess risk of death stemmed from cancer (MRR 1.73; 95% CI 1.46-2.05), cardiovascular disease (MRR 3.24; 95% CI 2.55-4.11), respiratory disease (MRR 5.66; 95% CI 4.00-8.03), and other disease-related causes (MRR 4.04; 95% CI 3.05-5.34).
They also examined to what extent factors associated with pain also predicted death. They found that age- and gender-adjusted risk of death was higher for participants in the two highest BMI categories than for people of normal weight: those who were 35-39 kg/m2 had an MRR of 5.54 (95% CI 5.08-6.03), and those 40kg/m2 or greater had an MRR of 9.02 (95% CI 8.23-9.89). They also observed that participants who reported no walking, versus those walking 1-100 minutes per week, had an MRR of 4.15 (95% CI 3.77-4.57). People who reported no moderate physical activity, versus those who reported 1-60 minutes of moderate physical activity per week, had an MRR of 2.95 (95% CI 2.74-3.19). Risk of death also was higher in current smokers, who had an MRR of 2.54 (95% CI 2.39-2.70) versus non-smokers.
When they adjusted the risk models to see how lifestyle variables like BMI, physical activity, smoking, and diet might attenuate the relationship between chronic widespread pain and excess mortality, they still saw an excess risk of cardiovascular and respiratory deaths, but no longer an excess risk of cancer death.
Lifestyle factors are important intervention targets for patients with chronic widespread pain, the authors concluded. They observed that optimal management of fibromyalgia should include exercise, for example, but that is not often provided in a structured way to help patients make long-term behavioral changes.
“Few patients with chronic widespread pain or fibromyalgia receive specific supported care in improving diet or stopping smoking,” they wrote. “The data from this study show that changing the habits of persons with chronic widespread pain to be similar to persons without chronic widespread pain could reduce mortality by around 35%.”
The researchers also incorporated their results into a meta-analysis with five other published reports to evaluate evidence linking pain and mortality. Studies included in the meta-analysis were observational, used a population sampling frame, identified widespread pain or chronic widespread pain (including fibromyalgia), and quantified the relationship between chronic widespread pain and death.
“The meta-analysis of this relationship shows that all 6 studies find excess mortality and estimate the excess risk across all studies at 59%, although there is significant heterogeneity,” the authors wrote. “Similar excesses of cancer and cardiovascular mortality are observed.”
“In UK Biobank, adjustment for lifestyle factors substantially reduced the excess risk, and this observation is consistent with them mediating the relationship between chronic widespread pain and mortality,” they added.