Editorials

Preventing osteoporosis, falls, and fractures among elderly people

Promotion of lifelong physical activity is essential 

In recent decades the number and incidence of injuries caused by falls among older adults have increased dramatically throughout the world, and without any population level intervention the increasing trend is likely to continuelargely because of an increasing number of older people.¹ About two thirds of these injuries are bone fractures, the hip fracture being the most common, the most devastating, and the most expensive that our healthcare systems have to face.¹

Regular exercise is probably the only method that may prevent osteoporotic fractures, the true end point of the entire osteoporosis problem, by preventing both osteoporosis and falls. The evidence seems stronger for exercise preventing osteoporosis. Human and animal studies have shown that physical activity can increase bone mass, density, and strength. ^{2 3} The starting age of activity is crucial: the benefit to bone is doubled if the activity is started before or at puberty rather than after it. ^{3 4} But bone tissue does also respond to exercise in adulthood, although this seems better at preserving bone than at adding new bone.^5-7 Nevertheless, the bone preserving action of exercise in adulthood may be important in maintaining bone strength and preventing osteoporotic fractures since only small percentages of bone mass and density preserved result in significant reductions in risk of fracture.⁸

The osteogenic effects of exercise are clearly site specificthat is, the effect is normally seen in only in loaded bone sites, ^{3 4 7} but the type, frequency, intensity, and duration of exercise that best produce the desired bone changes are not yet well determined. Current knowledge suggests that impact type exercise that creates versatile strain distributions throughout the bone structure can best improve bone strength.⁷ Regular sports such as squash, tennis, aerobics, volleyball, basketball, gymnastics, or weight and power training may best fulfil these demands. In older adults brisk walking, climbing up and down stairs, dancing, and adult age gymnastics and calisthenics seem suitable. ^{9 10}

Exercise can also improve gait, balance, coordination, proprioception, reaction time, and muscle strengtheven in very old and frail elderly people. ^{5 7} Despite this, its ability to decrease the risk of falling in general, or of injurious, fracture-inducing falling in particular, has remained questionable,¹¹ and when data from exercise trials in which an effect has been seen have been combined the average effect has usually been relatively small, 10-15%. ^{9 12} In interpreting these results we should, however, remember that the type of exercise has varied considerably between trials and an optimal exercise programme may never have been implemented. In other words, the type of activity may not have been optimal in protecting against falling, and its frequency and intensity may have been insufficient to show any clear reduction in the frequency of falling in the intervention groups. In this respect it is interesting that in a recent randomised trial in women aged 80 and over (in which particular attention was paid to these aspects of exercise) strength and balance training reduced the rate of falling by more than 30%.¹³

Although the effect of exercise in preventing falls and fractures in elderly people has not yet been proved, epidemiological studies (case-control and prospective cohort follow up studies) consistently show that both past and current physical activity does protect against hip fracture, reducing the risk by up to 50%. ^{9 10 14} Many of these studies have even found a dose response relation between the amount of exercise and the risk of fracture. The best combination seems to be vigorous past activity and moderate recent activity (vigorous activity in old age may increase the predisposition to falling accidents).¹⁰ Of various activity types, weight bearing activity seems most protective, and even daily walking and climbing stairs can be effective.⁹ Only a few epidemiological studies have focused on physical activity and fractures other than hip fracture, ^{9 15 16} and the findings have been partly contradictory.

Overall, however, the evidence strongly suggests that regular physical activity, especially if started in childhood and adolescence, is the only cheap, safe, readily available, and largely acceptable way of both improving bone strength and reducing the propensity to fall. It should therefore become an essential part of strategies aiming at controlling the alarming increase in osteoporotic fractures. Moreover, of all the methods of fracture prevention regular physical activity is the only one that provides considerable other health related benefits.¹⁷ For all these reasons, we must get both younger and older people moving.

Pekka Kannus, Chief physician. 

UKK Institute for Health Promotion Research, PO Box 30, FIN-33501 Tampere, Finland

1. Kannus P, Niemi S, Palvanen M, Parkkari J. Fall-induced injuries among elderly people. Lancet 1997; 350: 1174[Medline].
2. Gutin B, Kasper MJ. Can vigorous exercise play a role in osteoporosis prevention? Osteoporosis Int 1992; 2: 55-69[Medline].
3. Kannus P, Haapasalo H, Sankelo M, Sievanen H, Pasanen M, Heinonen A, et al. Effect of starting age of physical activity on bone mass in the dominant arm of tennis and squash players. Ann Intern Med 1995; 123: 27-31[Abstract/Free Full Text].
4. Haapasalo H, Kannus P, Sievanen H, Pasanen M, Uusi-Rasi K, Heinonen A, et al. Effect of long-term unilateral activity on bone mineral density of female junior tennis players. J Bone Miner Res 1998; 13: 310-319[Medline].
5. Nelson ME, Fiatarone MA, Morganti CM, Trice I, Greenberg RA, Evans WJ. Effect of high intensity strength training on multiple risk factors for osteoporotic fractures. A randomized controlled trial. JAMA 1994; 272: 1909-1914[Abstract].
6. Lohman T, Going S, Pamenter R, Hall M, Boyden T, Houtkooper L, et al. Effects of resistance training on regional and total bone mineral density in premenopausal women: a randomised prospective study. J Bone Miner Res 1995; 10: 1015-1024[Medline].
7. Heinonen A, Kannus P, Sievanen H, Oja P, Pasanen M, Rinne M, et al. Randomised controlled trial of effect of high-impact exercise on selected risk factors for osteoporotic fractures. Lancet 1996; 348: 1343-1347[Medline].
8. Hui SL, Slemenda CW, Johnston CC. Age and bone mass as predictors of fracture in a prospective study. J Clin Invest 1988; 81: 1804-1809.
9. Joakimsen RM, Magnus JH, Fønnebø V. Physical activity and predisposition for hip fractures: a review. Osteoporosis Int 1997; 7: 503-513[Medline].
10. Slemenda C. Prevention of hip fractures: risk factor modification. Am J Med 1997; 103: 65S-673[Medline].
11. Gillespie LD, Gillespie WJ, Cumming R, Lamb SE, Rowe BH. Interventions to reduce the incidence of falling in the elderly. In: The Cochrane Library. Cochrane Collaboration; Issue 4. Oxford: Update Software , 1997.
12. Province MA, Hadley EC, Hornbrook MC, Lipsitz LA, Miller JP, Mulrow CD, et al. The effects of exercise on falls in elderly patients. A preplanned meta-analysis of the FICSIT trials. JAMA 1995; 273: 1341-1347[Abstract].
13. Campbell AJ, Robertson MC, Gardner MM, Norton RN, Tilyard MW, Buchner DM. Randomised controlled trial of a general practice programme of home based exercise to prevent falls in elderly women. BMJ 1997; 315: 1065-1069[Abstract/Free Full Text].
14. Law MR, Wald NJ, Meade TW. Strategies for prevention of osteoporosis and hip fracture. BMJ 1991; 303: 453-459.
15. Kelsey JL, Browner WS, Seeley DG, Nevitt MC, Cummings SR, for the Study of Osteoporotic Fractures Research Group. Risk factors for fractures of the distal forearm and proximal humerus. Am J Epidemiol 1992; 135: 477-489[Abstract/Free Full Text].
16. O'Neill TW, Marsden D, Adams JE, Silman AJ. Risk factors, falls, and fracture of the distal forearm in Manchester, UK. J Epidemiol Comm Health 1996; 50: 288-292[Abstract].
17. Blair SN, Kohl HW, Gordon NF, Paffenbarger RSJ. How much physical activity is good for health? Annu Rev Public Health 1992; 13: 99-126[Medline].