Is the Pain killing you? Could Pain interference be a warning signal for midlife mortality?

Abstract

Although prior studies have documented an association between various measures of pain and mortality, none of those studies has evaluated whether the association between pain and mortality varies significantly by age. We suspect that pain-particularly pain that interferes with the ability to lead a normal life-could be an early warning sign that may portend increased risk of physical impairment and mortality later in life. In this paper, we investigated whether pain was associated with increased mortality risk, particularly in midlife. Data came from the Midlife in the US study, which sampled non-institutionalized, English-speaking adults aged 25-74 in the contiguous United States in 1995-96. Our analysis included 4041 respondents who completed a follow-up self-administered questionnaire in 2004-05, 2703 of whom completed another self-administered questionnaire in 2013-14. We modeled mortality through December 31, 2021. In demographic-adjusted models, pain interference was more strongly associated with mortality than other pain measures, and the association was stronger at younger ages. The hazard ratio for pain interference declined from 1.39 per SD (95% CI 1.26-1.54) at age 60 to 1.14 (95% CI 1.04-1.24) at age 90. Although potential confounders accounted for more than 60% of the association with premature mortality, pain interference remained significantly associated with increased mortality rates (HR = 1.13 at age 60, 95% CI 1.02-1.26). We found no evidence that the association between pain and mortality was driven by cancer. If anything, pain interference was more strongly associated with cardiovascular than cancer mortality. At the oldest ages, physical function is likely to be a better predictor of mortality than pain. Yet, pain interference may be a useful warning sign at younger ages, when there are fewer physical limitations and mortality rates are low. It may be particularly helpful in identifying risk of premature mortality in midlife, before the emergence of severe physical limitations.

Keywords: Chronic pain; Death; Mortality; Pain; Pain interference; United States.

Fig. 1

Smoothed plot of pain prevalence (by type) across age. Note: We plotted the percentage reporting any pain of the specified type across age for the pooled sample of observations at Waves 2 and 3 using the “lpoly” command in Stata 16.1 (StataCorp, 2019) to perform local mean smoothing—also known as the Nadaraya-Watson estimator (Nadaraya, 1964; Watson, 1964). This graph is restricted to the age range 34–90 because we have very few observations below age 34 and above age 90.

Fig. 2

Smoothed plot of the prevalence of chronic pain, pain interference, and physical limitations across age. Note: We plotted the percentage reporting chronic pain, pain interference, and physical limitations across age for the pooled sample of observations at Waves 2 and 3 using the “lpoly” command in Stata 16.1 to perform local mean smoothing—also known as the Nadaraya-Watson estimator (Nadaraya, 1964; Watson, 1964). This graph is restricted to the age range 34–90 because we have very few observations below age 34 and above age 90.

Fig. 3

Hazard ratios for the relative increase in mortality associated with measures of pain frequency for selected ages adjusted for demographic factors. Note: The hazard ratios are based on the models shown in Table S3 and are plotted on the log scale. The error bars represent the 95% confidence intervals. We do not show the hazard ratios for mortality below age 60 because only 63 (7%) decedents died below that age.

Fig. 4

Hazard ratios for pain interference by age Note: The hazard ratios (HRs) indicate the relative increase in mortality rates per SD of pain interference and are plotted on the log scale. The demographic-adjusted HRs are based on Model 6 from Table S4, while the fully-adjusted HRs are based on Model 5 (Table 1). The error bars represent the 95% confidence intervals. We do not show the hazard ratios for mortality below age 60 because only 63 (7%) decedents died below that age.