The authors have declared that no competing interests exist.
Conceived and designed the experiments: RW AT JM. Performed the experiments: RW AT JM. Analyzed the data: RW AT JM. Contributed reagents/materials/analysis tools: RW AT JM. Wrote the paper: RW AT JM.
Chronic musculoskeletal pain is common in older adults but the nature of its relationship with ageing is unclear. The objective for this study was to test the hypothesis that the onset of widespread pain would be associated with a decrease in healthy ageing.
Population-based prospective cohort study. A “healthy ageing” index was constructed across biomedical, physical, psychosocial and lay components. Analysis was performed with 2949 adults aged 50 years and over who had complete index scores at baseline, 3 and 6-year follow-ups.
At three and six year follow-up, 365 (16.8%) and 259 (14.3%) experienced the onset of widespread pain. The onset of widespread pain during the six-year period was associated with a 25% and a 46% decrease in healthy ageing index scores; this decrease was independent of age, sex, education, social networks, smoking status, alcohol consumption and physical inactivity. The decrease in healthy ageing attenuated to 20% and 39% following adjustment for diagnosed musculoskeletal conditions and analgesic and non-steroidal use.
The onset of widespread pain was associated with a decrease in healthy ageing throughout the six-year period. When pain increased over time, the markers of unhealthy ageing increased also. Strong analgesia was associated with unhealthy ageing. Research could now usefully test whether early identification, improved treatment and prevention of pain prior to old age may facilitate healthy ageing.
Chronic musculoskeletal pain is one of the most common disorders in older people
This is the first longitudinal study to examine the association between musculoskeletal pain and healthy ageing. The study tested the hypothesis that the onset of widespread musculoskeletal pain would be associated with a decrease in healthy ageing.
This study draws on a well-established population-based cohort study (the North Staffordshire Osteoarthritis Project, NorStOP) of the long-term prognosis of musculoskeletal pain in older people
A total of 13986 individuals returned a questionnaire of whom 9611 (68.7%) provided consent for the study team to access their medical records. Participants were followed up 3 and 6 years after the date of their baseline questionnaire. A total of 836 (8.7%) participants died over the six year period leaving 8775 participants. Of those 2949 (20.1%) provided complete data at baseline, 3 and 6 year follow-ups (n = 2949) (
Overall(n = 2949) | Withdrawn or incomplete data(n = 5826) | Died(n = 836) | P value | |
|
61.7 (0.25) | 64.3 (0.51) | 73.9 (0.25) | <0.001 |
|
78.97 (0.38) | 70.3 (0.39) | 55.9 (0.38) | <0.001 |
|
1334 (45.3%) | 2612 (44.8%) | 486 (58.1%) | <0.001 |
|
478 (16.4%) | 661 (11.7%) | 67 (8.3%) | <0.001 |
|
47.7 (0.38) | 42.0 (0.38) | 30.9 (0.57) | <0.001 |
|
55.1 (0.20) | 55.2 (0.88) | 47.3 (0.29) | <0.001 |
|
1154 (39.1%) | 2894 (49.7%) | 517 (61.8%) | <0.001 |
|
422 (14.3%) | 1398 (24.0%) | 293 (34.8%) | <0.001 |
All values are n (%) except * which are median (standard error).
Kruskal Wallis test for age and index, chi square for gender, education and social network.
Participants who experienced pain lasting for one day or longer in the past month were asked to indicate the site of their pain by shading on a blank body manikin (front and back views). Based on their pain reports participants were categorized into one of three groups: “no pain”, “regional pain” or “widespread pain”. Widespread pain was classified according to the American College of Rheumatology (ACR) criteria used in their definition for fibromyalgia
Those participants who reported no pain or regional pain at baseline or three years and who reported widespread pain at three and six year follow up respectively, were classified as having “new onset of widespread pain”.
Healthy ageing has been defined in a number ways: biomedical models emphasize the absence of disease and maintenance of physical and mental functioning; psychosocial models focus on life satisfaction and social participation; and lay models highlight accomplishment and contribution to life. Models that combine all three approaches better predict poor outcomes than one-dimensional approaches and have been proposed to evaluate independence in older adults
NorStOP was designed to measure the impact of pain in older adults and capture multiple constructs of ageing
Domain of healthy ageing | Variables | Score (0–1) |
|
Limitation in vigorous activitiesLimitation in moderate activitiesLimitation in lifting or carrying groceriesLimitation climbing one flight of stairsLimitation bending, kneeling or stoopingLimitation walking half a mileLimitation bathing and dressing | For each item:1– No limitation0.5– Limited a little0– Limited a lot |
|
Self-rating of health | 1– Excellent, 0.75– Very good, 0.5– Good, 0.25– Fair, 0 - Poor |
Unhealthy weight | 1 = Normal weight (20–24.9)0.5 = Overweight (25–29.9)0 = Underweight (<20) & Obese (30+) | |
Chest problemsHeart problemsDiabetesDeafnessProblems with eyesightRaised blood pressureSuffered a fallDizziness or unsteadinessWeakness in an arm or leg | For each item:1- Absent0-Present | |
Cognitive impairment | 1– Not impaired0- Impaired | |
|
Anxiety | 1– Non-case, 0.5– Possible, 0 - Probable |
Depression | 1– Non-case, 0.5– Possible, 0– Probable | |
Sleep problems | 1– No sleep problems0 - Any sleep problem | |
|
Accomplishment of daily activities | 1-No limitation in accomplishing daily tasks0-Not accomplishing daily tasks |
Feeling of calm and peaceFeeling of having a lot of energy | For each item:1– All the time0.8– Most of the time0.6– A good bit of the time0.4– Some of the time0.2– A little bit of the time0– None of the time | |
Financial strain | 1–Manage/comfortable0- Strain/have difficulty | |
|
Restrictions in mobility within homeRestrictions in mobility out with the homeRestrictions in self-careRestrictions looking after the homeRestrictions looking after belongingsRestrictions communicating with othersRestrictions in social activities | For each item:1– Not restricted0 - Restricted |
At each time point the healthy ageing index score ranges from 0 to 100; higher scores indicate a greater level of “healthy ageing”. The formula to calculate the score at each time point is: (total score/33)*100.
To test the ability of the index to measure healthy ageing, the relationship with mortality was examined. Lower index scores were associated with an increased risk of mortality. The median baseline healthy ageing index scores for the 836 participants who died during the six year period was significantly lower than for those who were included in the analysis (n = 2949) (57.7 cf 79.0; p<0.001).
Demographic factors included in the analysis as potential confounders were age, sex, social networks (Berkman-Syme Social Network Index
The baseline characteristics were described overall and stratified by baseline pain status. Differences between the baseline pain groups for healthy ageing index score and age were tested using Kruskal Wallis test and for education, social network, smoking, alcohol consumption, physical inactivity, diagnosis of musculoskeletal condition, prescription of analgesia and anti-inflammatories using a chi-square test. The distribution of the healthy ageing index score had moderate skewness and kurtosis (baseline index: skewness 1.09; kurtosis 4.01) and was log transformed. The results were presented as percentage change in healthy ageing index score. This was calculated from the beta coefficients (β) of each variable in the model using the formula (100* (exp(β) -1)). To test the study hypothesis that the onset of widespread pain would be associated with a decrease in healthy ageing index score, a mixed modelling regression approach was used to analyse the longitudinal data of this study
Sensitivity to subject attrition and missing data was examined via probability-weighted analysis for survey data
All analyses were conducted using Intercooled Stata version 9.2 (StataCorp, College Station TX).
At baseline, median (Standard Error (SE)) age was 61.7 (0.25) years, 54.7% were women, 83.8% had a high school education only, and 48.1% had medium/low social networks (
Overall(n = 2949) | No pain(n = 873) | Regional pain(n = 1296) | Widespread pain(n = 780) | P value | |
|
61.72 (0.25) | 61.94 (0.25) | 61.91 (0.25) | 61.30 (0.51) | 0.17 |
|
78.97 (0.33) | 87.06 (0.33) | 78.90 (0.47) | 68.24 (0.78) | <0.001 |
|
|||||
(Female) | 1592 (54.71) | 431 (51.68) | 685 (52.85) | 476 (61.03) | <0.001 |
|
|||||
(no further education) | 2415 (83.77) | 673 (81.67) | 1072 (83.49) | 670 (86.45) | 0.033 |
|
|||||
(med/low) | 1,419 (48.1) | 405 (58.61) | 620 (56.83) | 394 (58.81) | 0.644 |
|
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PreviousCurrent | 1190 (40.9)369 (12.7) | 317 (38.0)97 (11.6) | 545 (42.1)161 (12.4) | 328 (42.1)111 (14.2) | 0.06 |
|
|||||
Weekly/monthlyNever/yearlyDaily | 1604 (55.2)618 (21.3)684 (23.5) | 461 (55.0)179 (21.5)194 (23.7) | 727 (56.3)242 (18.7)329 (25.1) | 416 (53.1)197 (25.3)166 (21.3 | 0.01 |
|
|||||
All daysMost daysSome daysFew/no days | 1135 (39.6)1007 (35.1)530 (18.5)198 (6.9) | 383 (46.7)301 (36.7)105 (12.8)32 (3.9) | 526 (41.2)435 (34.1)241 (18.9)75 (5.8) | 226 (29.3)271 (35.1)184 (23.8)91 (11.8) | <0.001 |
|
|||||
Every dayEvery other/twiceweekly<1 weekNever | 436 (15.2)1365 (47.6)589 (20.5)477 (16.6) | 141 (17.2)447 (54.6)142 (17.3)89 (10.9) | 199 (15.6)616 (48.2)255 (19.9)209 (16.3) | 96 (12.5)302 (39.3)192 (25.0)179 (23.3) | <0.001 |
|
724 (24.6) | 90 (10.3) | 358 (27.6) | 276 (35.4) | <0.001 |
|
|||||
NoneBasicWeakModerateStrongVery strong | 1283 (43.5)301 (10.2)365 (12.4)251 (8.5)715 (24.3)34 (1.2) | 533 (61.1)88 (10.1)101 (11.6)40 (4.6)110 (12.6)1 (0.11) | 533 (41.1)155 (12.0)160 (12.4)117 (9.0)314 (24.2)17 (1.3) | 217 (27.8)58 (7.4)104 (13.3)94 (12.1)291 (37.3)16 (2.1) | <0.001 |
|
1197 (40.6) | 237 (27.1) | 562 (43.4) | 398 (51.0) | <0.001 |
All values are n (%) except * which are median (standard error).
Kruskal Wallis test for age and index, chi square for gender, education and social network.
Independent of pain status mean healthy ageing index scores decreased by 6.2% over the six year follow up period (exp(0.06)-1)*100; i.e. 0.06 was the beta coefficient decrease in the healthy ageing index score (log of healthy ageing index) which corresponded to a 6 year increase, the formula above transforms the beta coefficient to a percentage change in the original healthy ageing index score at baseline) (
Model (I) | Model (II) | Model (III) | |
|
97.17(0.013)(97.15, 97.20) |
97.98(0.046)(97.89, 97. 93) |
97.99(0.052)(97.91, 98.08) |
|
−6.2%(0.004)(−5.1%, −7.2%) |
−6.2%(0.004)(−5.1%, −7.2%) |
−6.2%(0.005)(−5.0%, −7.3%) |
|
|||
|
Referent | Referent | Referent |
|
−19.7%(0.012)(−17.3%, −23.3%) |
−20.9%(0.013)(−18.5%, −24.6%) |
−19.1%(0.016)(−15.6%, −22.9%) |
|
−40.5%(0.014)(−36.3%, −43.3%) |
−39.5%(0.016)(−34.9%, −43.9%) |
−32.8%(0.018)(−28.1%, −37.7%) |
|
− | −9.1%(0.021)(−4.7%, −9.1%) |
−8.1%(0.023)(−3.9%, −12.5%) |
|
− | −1.4%(0.001)(−1.1%, −1.6%) |
−1.1%(0.001)(−0.8%, −1.3%) |
|
− | −5.7%(0.021)(−1.5%, −10.2%) |
−5.5%(0.023)(−1.6%, −9.7%) |
|
− | −6.9%(0.028)(−1.2%, −10.1%) |
−3.5%(0.031)(−2.0%, −8.9%) |
|
− | −8.9%(0.015)(−5.8%, −12.3%) |
−7.2%(0.013)(−4.2%, −10.2%) |
|
− | 4.1%(0.03)(−1.3%, 9.6%) | 5.1%(0.03)(−0.03%, 10.5%) |
|
− | −3.3%(0.03)(−8.6%, 1.6%) | −3.0%(0.02)(−8.3%, 1.6%) |
|
− | −19.1%(0.012)(16.2%, 21.9%) |
−16.8%(0.009)(−14.2%, −19.5%) |
− | −5.3%(0.008)(−3.7%, −7.3%) |
−3.9%(0.017)(−2.3, −5.7) |
|
|
− | − | −9.1%(0.008)(−7.8%, −10.6%) |
|
− | − | −0.2%(0.001)(−0.1%, −0.4%) |
|
− | − | −112.1%(0.024)(−6.9%, −17.7%) |
|
|||
Level 2 variance (Individuals) | 0.28(0.009)(0.26,0.30) | 0.21(0.007)(0.20,0.23) | 0.18(0.007)(0.17, 0.20) |
Level 1 variance (Repeated measurements) | 0.103(0.002)(0.099,0.106) | 0.10(0.002)(0.010,0.11) | 0.10(0.002)(0.10, 0.10) |
|
11229 | 8503 | 8171 |
All values are followed by standard error and 95% confidence intervals. Model I: Addition of painstatus as a time-varying variable (i.e. over the follow up period subjects can move between pain states). Model II: Adjustment for potential confounders: age, gender, educational attainment, social networks, smoking status, alcohol consumption and physical inactivity. Model III: Further adjustment for use of pain analgesia and non-steroidals, and diagnoses of chronic musculoskeletal conditions’.
p<0.001, CI Confidence interval, – Variable not included.
Among subjects with regional pain the onset of widespread pain was associated with a 24.8% decrease in healthy ageing index score (i.e. the decrease in healthy ageing index score for those with widespread pain compared to those with regional pain was 18.6% +6.2% (time)). The decrease in healthy ageing index score was attenuated to 19.9% following adjustment for diagnosed musculoskeletal conditions and analgesic and non-steroidal use.
For completion, we also report the associations with the onset of regional pain. At three and six year follow-up, 335 (38.5% of those with no pain at baseline) and 267 (38.0% of those with no pain at three year follow-up) had experienced the onset of regional pain (
Between-subject variation explained 64.3% of the total healthy ageing index score variance (R2 for between subject variation/R2 for total variance; 0.18/0.28) while within subject variation explained 35.8%. The addition of diagnosed chronic musculoskeletal conditions and use of analgesics and non-steroidals improved model goodness of fit by 4.0% (i.e. AIC decreased from 8503 to 8171) (
This study has shown that among older people, the onset of widespread pain was associated with a composite measure of unhealthy ageing. For all three pain states, older adults aged less healthily across the six-years of follow-up. However the onset of widespread pain during the 6 year period, independent of age and time, was associated with a significant decrease in healthy ageing index scores. Socio-demographic factors were significantly associated with a decrease in healthy ageing, particularly female gender. In this study adjustment for analgesia attenuated the relationship between widespread pain and healthy ageing index score. However, the extent to which analgesia was a marker of severe pain or was ineffective in relation to the impact of pain must await long-term intervention studies.
There are no studies with which to directly compare these data. It is clear that pain impacts on a number of body systems and, particularly widespread pain, is associated with poor outcomes across biomedical, psychological and social domains
This study has a number of strengths. The sample was derived from a large population-based study of older community dwelling individuals. Data was collected prospectively and allowed the relationship between the onset of widespread pain and changes in healthy ageing index scores to be determined. The concept of ’healthy ageing’ captures multiple outcomes and the complexity and quality of increasing longevity
Study limitations were: The healthy ageing index was constructed using self-report data. Although this is susceptible to measurement error, the self-report of impairments and functional problems (e.g. falls) have been shown to be accurate in older adults
Domain | Free of widespread pain(n = 1622) | Onset of widespread pain(n = 365) | % difference (95% CI) | P-value |
|
48.7% | 60.0% | 11.2 (5.6, 17.0) | <0.001 |
|
33.7% | 36.4% | 2.8 (−2.7, 8.2) | 0.31 |
|
18.1% | 25.8% | 7.6 (2.8, 12.5) | <0.001 |
|
41.3% | 49.9% | 8.6 (2.9, 14.2) | 0.003 |
|
13.0% | 20.0% | 7.1 (2.6, 11.4) | <0.001 |
CI Confidence interval. Chi square test provides p values.
These findings provide evidence suggesting that the onset of widespread pain was associated with a decrease in healthy ageing in older adults. Prevention and treatment of pain is complex, particularly in older adults due to comorbidity and polypharmacy. This study suggests that further prospective cohort and intervention studies would be justified to establish whether early identification, improved treatment and prevention of pain prior to old age could promote healthy ageing, as well as to understand the mechanisms by which the onset of widespread pain increased the risk of unhealthy ageing.
We would like to thank the administrative and health informatics staff at Keele University’s Arthritis Research UK Primary Care Centre and the doctors and staff of the participating general practices.