One group of researchers conducted an individual level data meta-analysis of the results of four trials conducted by their fall prevention research group to estimate the overall effect of the Otago individualised strength and balance exercise programme on falls and injuries.14 The study demonstrated a 35% reduction in the risk of an injurious fall (moderate or serious), a result similar to that presented here, but it failed to show a significant reduction in serious fall related injuries. A more recent review including three additional trials of the Otago exercise programme,52 failed to support the previous finding that the programme significantly reduced the risk of injurious falls, possibly because of a lack of access to individual level data or because of differences in the implementation and supervision of the programme (as suggested by the significantly lower compliance rates reported in the three additional trials than in the first four).
The recent Cochrane review of fall prevention interventions conducted a specific analysis to examine the effect of exercise interventions on the risk of fall related fractures and obtained similar results (pooled relative risk 0.34, 95% confidence interval 0.18 to 0.63).7 Of the six trials included in the Cochrane analysis, five are also included in our analysis. We excluded the one study because participants were recruited in the hospital while in the acute phase of an injury (hip fracture) so that the results of this trial may not be comparable to those not recruiting on the basis of an injury.53 Inversely, we included one study29 that compared an exercise intervention including balance, gait, and strengthening and flexibility exercises to a “wellness” exercise programme designed decrease the severity of the resulting trauma, which may explain why the estimated protective effect of exercise is stronger for severe injurious falls than for all injurious falls, the latter including severe but also minor and moderate injuries.
Although exercise reduces the severity of injury, the pooled effect of exercise on reducing all injurious falls (37%) was larger than the effect of exercise on falls resulting in medical care (30%) (which are presumably more severe). However, medical care seeking behaviour is influenced by the type and availability of care and sociodemographic characteristics as well as by other personal factors such as personality, pain tolerance, and anxiety.42 43 Accordingly, the mere fact that medical care was sought does not necessarily imply that an injury was more severe, although this is probably less true when different categories of injurious falls are examined within the same population. Of the 10 studies included in the analysis of all injurious falls, five also contributed to the analysis of falls resulting in medical care,13 21 25 26 28 and three also contributed to the analysis of severe injurious falls.13 25 26 Within these studies, the point estimate of the effect of exercise decreased from all injurious falls to falls resulting in medical care for all studies but one, and from falls resulting in medical care to severe injurious falls for all studies. These results support the argument that exercise reduces the severity of the injuries caused by falls.
Other risk factors are specific to the risk of trauma during a fall, and correction of these factors by exercise may also help explain the larger protective effect of exercise on serious injuries such as fractures. In particular, low bone mass is a major determinant of the risk of fracture once a fall begins. In three of the five trials included in the analysis of fall related fractures,29 33 34 the intervention was specifically designed to improve bone mass and hence included high intensity impact exercise in addition to balance, gait, and functional exercises. It resulted in a significant positive effect on bone mass at bone sites that varied with the study. However, these interventions were tested in women who were on average less than 75 years of age and did not have specific risk factors for falling. Hence, they may not be appropriate for older people aged more than 75 years, who are at the highest risk of falls and fractures, especially hip fractures.
The large estimated pooled effect of more moderate intensity exercise training on serious injuries found in this meta-analysis suggests that reducing the risk of falling and improving protective responses during a fall are important and feasible means of preventing fractures and other serious injuries in elderly people, as others have emphasised.44 45 46 47 48 This finding is especially important because large epidemiological studies have shown that most fractures in the population occur in people at moderate “bone risk” for their age.49 50 Hence, while prescription of antiosteoporotic drug treatments is currently recommended for older people with low bone mass, who are at the highest risk of fracture, additional effective strategies t