In a representative sample of an Italian population aged 65 years and older, the 1-year cumulative prevalence of frequent back pain was 31.5%. This finding consistent with most studies reporting back pain prevalence in the general population (36%–37%).29,30
In particular, the 31.5% 1-year prevalence of frequent back pain found in our study is consistent with the prevalence of back pain reported in the Saskatchewan adult population (6-month prevalence = 23.7%; and following 6-months incidence = 8%).31
In agreement with most studies performed in U.S. populations, back pain was more common in women than men, and the most frequent location was the lower back.29
Women generally report more back pain than men,29
perhaps because of higher incidence of painful spine disease (e.g.
, vertebral microfractures), to more frequent practice of activities that may trigger back pain (e.g.
, household chores), and perhaps to “complaining” being more socially acceptable for women than for men. Consistent with most literature,32,33
we found that the prevalence of back pain tended to be lower in the oldest age group, showing a decline above the age of 85 in women and of 90 in men. Previous studies have found that very old persons tend to report systematically less pain,32
perhaps because of a recall bias, the acceptance of some pain as “natural” in old age, and/or underestimation of pain compared with more serious health problems that occur in the same time-frame. It is also possible that the very old experience less pain because they tend to perform less physical efforts and are less likely to be affected by work-related stress. Additionally, older participants may be a selected population that is less affected by back pain.
The 13.5% prevalence of back pain participants who reported regular analgesic drug use in the previous 2 weeks is consistent with the findings of a recent study performed in Spain (14.6%)34
but substantially lower than the 35% to 38% prevalence reported by less recent studies performed in the United States.35
The finding that women presented both significantly more severe pain and were more likely to use drugs than men is consistent with the literature.4
Since high CES-D score was an independent predictor of back pain in our population, and was significantly higher in women, both in the back pain and in the no-back pain group, depression may partially explain this sex-related difference, suggesting that selected older back pain patients may benefit from treatment with antidepressants.
In survivors (70+) of the Framingham study, 18% to 34% of all functional limitations were attributable to back pain, and, similar to our analysis, pushing or pulling a large object was significantly associated with back pain.5
In our study, more than three fourths of our back pain population were not functionally impaired because of back pain, showing that in most cases back pain was not associated with disability. Out of the whole study population, 7.4% reported a back pain-related functional limitation in the past month; our results confirm previous findings of associations between back pain and the self-reported ability to perform heavy household chores, cutting toenails, and carrying a shopping bag.4
Further, we found that back pain was also associated with difficulty in using public transportation, but not with the ability to perform more basic self-care and mobility tasks. Interestingly, the activities that were significantly limited in participants with back pain were often the same activities reported as triggers for back pain onset.
In a recent Danish study, musculoskeletal, lung and cardiovascular disease, gastric ulcer, headache/migraine, and low physical functioning were significant independent correlates of back pain.14
In our analysis, the only comorbidities associated with back pain were suggesting that back pain in the elderly should not necessarily be inscribed into a picture of general poor health.36
In preliminary analyses, we found that both a higher score of depressive symptoms and a lower score on the PM questionnaire were significantly correlated with back pain. The association between back pain and depression has been well documented in the general population; in longitudinal studies, depression was found to be a risk factor for subsequent back pain, while results about the reverse association are conflicting.13
PM is a complex psychologic dimension conveying self-esteem, self-efficacy, and locus of control, a basic determinant of ability to cope with stressful conditions, including disease.37
Both depression and the experience of inescapable loss related to chronic conditions may lower self-esteem and mastery; in particular, it has been hypothesized that depression may produce lower PM and increased psychologic vulnerability in older persons.38
In our multivariate analysis, depression, but not PM, maintained a significant association with back pain, suggesting that, at least in this population, depression may be the mediating mechanism that buffers the association between back pain and PM.
Poor lower-extremity strength was significantly associated with back pain. Because of the cross-sectional nature of our study, no conclusions can be drawn about the direction of causality. Poor strength may be a precursor of back pain or may be the consequence of a back pain episode. To shed more light into the directionality of this causal pathway, the association between leg strength and back pain should be examined in a longitudinal fashion.
Back pain correlates identified in studies performed in younger populations, such as smoking, low education, and high BMI, were not associated with back pain in our analysis, while history of work-related physical activity was no longer statistically significant in the multivariate analysis. Altogether, our findings suggest that many factors significantly associated with back pain in working-age adults may be no longer important in old age.14
This hypothesis should be verified in a longitudinal setting.
A limitation of this study is the lack of radiologic examinations of the spine, which could not be systematically performed in our population sample because of ethical reasons. Limited trunk extension was the only physical measure that maintained an association with back pain in the multivariate analysis. It is well known that lumbar flexion range of motion is poorly related to pain and disability in back pain.30
Prospective studies should evaluate the possibility that variations in trunk extension may have a closer association with back pain in older adults. Our findings are consistent with the notion that the aging spine becomes progressively stenotic. However, because of the lack of spine radiologic images in our assessment, this hypothesis could not be verified. Clinically, movements into trunk extension often tend to exacerbate lumbar symptoms seen in older adults. This hypothesis, if confirmed, would have meaningful implications for the rehabilitative approach to these patients. Thus, our findings should be verified in a clinical series of patients in whom a spine radiograph is available.
Since we could not calculate Cobb’s angle on spinal radiographs, we chose the distance C7-wall as an index of thoracic hyperkyphosis: the independent association between back pain and the distance C7-wall, suggests a possible association of back pain with osteoporotic vertebral microfractures, which are the main cause of thoracic hyperkyphosis in the elderly; this interpretation is not necessarily in contrast with the lack of a significant age- and gender-adjusted association between back pain and bone density evaluated at the lower leg by pQCT, as the individual time-related pattern of bone mass loss may be quite different in the spine and in the lower limbs.39
Claims that vertebral osteoporosis play a role in back pain have not been confirmed.39
It is possible that, apart from the acute pain, the association may occur only when the deformities consequent to vertebral fracture produce into postural disalignment, as represented by the distance C7-wall and/or impaired mobility (trunk extension), and this should also be verified in clinical studies using spinal x-ray images. The significant association found between back pain and the report of pain in other joints suggests that, with increasing age, back pain often presents in the context of a broader pattern of musculoskeletal pain.1
Pain involving the back and one or more lower extremity joint may be related to a generalized disorder, such as osteoarthritis, but may also depend on pain radiation and pain-induced alterations of posture and gait, with consequent joint stress other than the primary source of pain.
Persons affected by back pain were significantly less physically active in the year before the interview. Given the cross-sectional nature of these data, we cannot make inferences on whether back pain was a cause of mobility limitation or a maintained physical activity had a protective effect against the development of back pain.