Bone health in older people

Age and Ageing is the journal of health in older age and it is not surprising that there has been a rich seam of publications on aspects of bone health over the years. It is timely to review some of these papers in order to present a critical mass of material that may engage readers and enhances their understanding of common conditions, particularly osteoporosis and fragility fractures, which are the unwanted consequences of poor bone health.

Kyphosis and vertebral fracture

Thirty years ago, Milne and Williamson published the results of their longitudinal study on kyphosis in older men and women. They found an increase in kyphosis and vertebral wedging with advancing age, but wedging accounted for less than 50% of the kyphosis. They also reported that kyphosis, but not vertebral wedging, predicted mortality in men but not in women. More recently, Siggeirsdottir et al studied a cohort in Iceland, finding that over more than five years’ follow up, clinical vertebral fracture was associated with the worst function and greatest health burden (including a greater length of hospital stay) when compared with those who had sustained fractures at other sites or no fracture at all.

Predictors of fracture and fracture outcome

The combined cost of hospital and social care for patients with a hip fracture in England has been estimated at £1.9billion per annum. The identification of predictors of fracture risk is important to both develop case finding tools and strategies to modify risk factors. Rapp et alreviewed the prediction of 44,000 femoral fractures during 5,319,438 person-years of follow in Germany. Comparing those at home without “care needs” with those at home with “care needs” and care home residents, there was a gradient of fracture rate of 6.13, 34.53 and 43.05 femoral fractures/1,000 person-years for women and 2.66, 20.34 and 31.09 for men, showing a higher fracture rate in women than men at all ages but a similar difference between those who are more and less independent for both genders.

In a study using population-based health survey data from England for 24,725 adults aged over 55 years, Scholes et al rather surprisingly found that 49% of men and 40% of women reported a previous fracture in their lifetime. It is interesting that hip and forearm fractures were commoner in women but the greatest discrepancy between the genders was in fractures classified as “other”, comprising 22% and 11.7% of fractures in men and women respectively. Perhaps this relates to historic trauma, rather than fragility fracture risk? Of further interest is that higher alcohol consumption is a risk factor in both sexes, while former smoking habit and long-standing illness are risks for men but being separated or divorced, poorer self-reported health and obesity are risk factors for women.

Kannergard et al found that, among 41,000 Danish patients sustaining a hip fracture, men had a greater mortality, which could not be explained by comorbidity or medications alone and, in a meta-analysis incorporating fifty-three studies including 544,733 participants,Smith et al also found that men had a greater mortality from hip fracture. Mortality was also greater in those care home residents, those with poorer anaesthetic assessment scores or sustaining an intracapsular fracture, while an abnormal ECG, cognitive impairment, older age and pre-fracture immobility were the greatest predictors of death up to 12 months. Further focusing on men, in another large prospective study of fall and fracture risk in more than 10,000 males (MrOS), Rosengren et al reported that hand-grip and a timed six-metre walk discriminated fallers with a fracture from both fallers with no fracture and non-fallers. A picture is emerging that female sex is associated with increased fracture risk, but worse outcomes are seen in men after fracture.

Lifestyle, frailty and bone health

While osteoporosis-specific advice can focus on aspects of nutrition, activity and other factors, there may be tensions in offering wider advice for those at increased risk of, say, osteoporosis and cardiovascular disease. It is therefore reassuring to see that Khatib et alstudied fracture outcomes in 26,335 adults, aged 55 years or older, participating in antihypertensive drug treatment trials. They found that smoking and low physical activity were significantly associated with greater fracture risk and that, together with higher alcohol consumption, these effects were cumulative, with an associated hazard ratio of 1.17 for one; 1.73 for two and 2.37 for three risk factors (P for trend <0.001).

However, among our more dependent patients, frailty is becoming a significant challenge, and in a study of 1,504 community-dwelling men aged 60–79 years, Tajar et al found that frailty was positively associated with lower plasma 25(OH) vitamin D and higher PTH levels in older men, while Krishnan et al found that frailty predicted mortality after hip fracture in men better than the results of Comprehensive Geriatric Assessment (CGA). However, the debate continues as to whether this reflects reverse causality: frailty causing (rather than caused by) poor vitamin D status and, importantly, whether treating poor vitamin D status is worthwhile in these highly dependent patients.

Environment and fracture

Whatever the gender differences and the potential impact of sarcopenia and frailty, fracture risk may potentially be modified by the environment, with Simpson et al finding that wooden carpeted floors were associated with the lowest rates of fractures, among care home residents and it good to see this observation complemented as Drahota et al piloted the introduction of special flooring (8.3-mm vinyl floor over fibreglass mat with PVC foam backing), compared with normal flooring in a general hospital setting. Although this was a small trial and the intervention was not blinded, fall rates were similar in both arms 35 falls (31 fallers) in the intervention group, of which 22.9% were injurious, compared with 42.4% of 33 falls (22 fallers) in the control group with an injury incident rate ratio (IRR) of 0.58 [95% CI = 0.18–1.91], which was not significant but favoured the intervention. The researchers estimated that a future trial would need more than 33,000 person bed-days per arm. Surely this is worth considering in the NHS?

Exercise

Finally, Ebrahim et al showed the complexity of lifestyle modification outcomes in their study of advice to promote brisk walking in older women, compared with a control group performing upper limb exercises. They saw a greater fall in bone mineral density at the femoral neck in the placebo group compared with the intervention, which just failed to meet statistical significance (p= 0.056), but the cumulative risk of falls was higher in the brisk-walking group (excess risk of 15 per 100 person-years, 95% CI 1.4–29 per 100 person-years, P < 0.05). The study was not large enough to show a difference in fracture incidence, but the risks of increasing exercise in older people is a potentially unwelcome message.

Conclusions

These papers were chosen for their novelty and their influence, with more than 350 citations in peer reviewed journals. They share themes of clinical relevance, looking at bone health in the old and the oldest old to come up with some surprising results. The earlier studies ofMilne and Williamson and Ebrahim have anticipated more recent research in the areas of vertebral deformity and falls risk. The observations on male osteoporosis and fracture risk remain novel, as we learn more about the differences in ageing between the genders, and the importance of frailty and sarcopenia will continue to challenge some of our former preconceptions about bone mineral density compared with the importance of age and other clinical risk factors in determining the risk of fragility fracture and its outcomes.

The Collection

Pilot cluster randomised controlled trial of flooring to reduce injuries from falls in wards for older people
By Drahota, A. K., Ward, D., Udell, J. E., Soilemezi, D., Ogollah, R., Higgins, B., Dean, T. P., and Severs, M.

Randomized placebo-controlled trial of brisk walking in the prevention of postmenopausal osteoporosis
By Ebrahim, S., Thompson, P. W., Baskaran, V. and Evans, K.

Excess mortality in men compared with women following a hip fracture. National analysis of comedications, comorbidity and survival
By Kannegaard, P. N., van der Mark, S., Eiken, P. and Abrahamsen, B.

Pre-operative indicators for mortality following hip fracture surgery: a systematic review and meta-analysis
By Smith, T., Pelpola, K., Ball, M., Ong, A., and Kyaw Myint, P.

Predicting outcome after hip fracture: using a frailty index to integrate comprehensive geriatric assessment results
By Krishnan, M., Beck, S., Havelock, W., Eeles, E., Hubbard, R. E. and Johansen, A.

A longitudinal study of kyphosis in older people
By Milne, J. S. and Williamson, J.

Femoral fracture rates in people with and without disability
By Rapp, K., Becker, C., Cameron, I. D., Klenk, J., Kleiner, A., Bleibler, F., König, H. H. and Büchele, G.

Epidemiology of lifetime fracture prevalence in England: a population study of adults aged 55 years and over
By Scholes, S., Panesar, S., Shelton, N. J., Francis, R. M, Mirza, S., Mindell, J. S., and Donaldson, L. J.

Inferior physical performance test results of 10,998 men in the MrOS Study is associated with high fracture risk
By Rosengren, B. E., Ribom, E. L., Nilsson, J. Å, Mallmin, H., Ljunggren, Ö, Ohlsson, C., Mellström, D., Lorentzon, M., Stefanick, M., Lapidus, J., Leung, P. C., Kwok, A., Barrett-Connor, E., Orwoll, E. and Karlsson, M. K.

Effect of vertebral fractures on function, quality of life and hospitalisation the AGES-Reykjavik study
By Siggeirsdottir, K., Aspelund, T., Jonsson, B. Y., Mogensen, B., Launer, L. J., Harris, T. B., Sigurdsson, G. and Gudnason, V.

Does the type of flooring affect the risk of hip fracture?
By Simpson, A. H. R. W., Lamb, S., Roberts, P. J., Gardner, T. N., and Evans, J. G.

Impact of lifestyle factors on fracture risk in older patients with cardiovascular disease: a prospective cohort study of 26,335 individuals from 40 countries
By Khatib, R., Yusuf, S., Barzilay, J. I., Papaioannou, A., Thabane, L., Gao, P., Joseph, P. G., Teo, K., and Mente, A.

The association of frailty with serum 25-hydroxyvitamin D and parathyroid hormone levels in older European men
By Tajar, A., Lee, D. M., Pye, S. R., O'Connell, M. D. L., Ravindrarajah, R., Gielen, E., Boonen, S., Vanderschueren, D., Pendleton, N., Finn, J. D., Bartfai, G., Casanueva, F. F., Forti, G., Giwercman, A., Han, T. S., Huhtaniemi, I. T., Kula, K., Lean, M. E. J., Punab, M., Wu, F. C. W. and O'Neill, T. W.