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Exercise prevents disability in older adults

 

As the population ages, the proportion of people having difficulty performing essential everyday activities is on the increase. This type of disability affects people’s quality of life, limits their independence and increases the requirements for both formal and informal care. Clearly, there is a need to develop strategies to increase older adults’ active years of life. This study examines whether an exercise programme can prevent this type of disability, known as activities of daily living (or ADL) disability.

Bottom line

Exercise reduces the short-term incidence of ADL disability in older people with knee osteoarthritis.


Reference

BWJH Penninx et al. Physical exercise and the prevention of disability in activities of daily living in older persons with osteoarthritis. Archives of Internal Medicine 2001 161: 2309-2316.

Study

Participants were 250 adults, initially free of ADL disability, from the Fitness Arthritis and Seniors Trial, a randomised controlled trial of aerobic or resistance exercise among older adults with knee osteoarthritis. Participants were recruited from the community through local advertisements and mailings. Eligibility criteria were: aged 60 years or older; pain in the knee/s on most days; difficulty with at least one activity, e.g. climbing stairs; and radiographic evidence of knee osteoarthritis. Exclusion criteria were: a medical condition that prevented safe participation in an exercise programme; inflammatory arthritis; exercising regularly; and an inability to walk 128 m in six minutes.

Participants were randomly assigned to one of three groups: 80 in the attention control group; 88 in the aerobic exercise programme; and 82 in the resistance exercise programme. Both programmes were supervised by exercise therapists.

Attention control group . Participants attended monthly group sessions on arthritis management (months 1 to 3); and were telephoned to update health status and provide support (months 4 to 18).

Aerobic exercise programme . Participants attended an indoor track three times a week for one hour, consisting of 10 minutes warm-up/cool-down and 40 minutes walking (months 1 to 3); and were visited and telephoned to offer assistance and support in developing a walking programme at home (months 4 to 18).

Resistance exercise programme . Participants attended three one-hour sessions a week, consisting of 10 minutes warm-up/cool-down and 40 minutes of 2 sets of 12 repetitions of 9 exercises, e.g. biceps curl, leg curl (months 1 to 3); and continued these exercises at home (months 4 to 18).

Demographics and clinical conditions were assessed at baseline, including hypertension, chronic co-morbid conditions (e.g. coronary heart disease) and intensity of knee pain. Self-reported disability was assessed with a 30-item questionnaire every three months during the 18-month follow-up period. ADL disability was defined as experiencing difficulty in bathing, eating, dressing, transferring from a bed to a chair or using the toilet.

Results

The average age of participants, free of disability at baseline, was 69 years and 68% were women. Demographics, co-morbidity, intensity of knee pain, walking speed and disability scores did not differ across the three groups. Adherence to the exercise programmes declined over time, with 56% completing the aerobic exercise programme and 61% completing the resistance programme.

The incidence of ADL disability was lower in the exercise groups (37%) than in the attention group (53%).

Participation in an exercise programme was associated with a 43% reduced risk of ADL disability (relative risk 0.57, 95% confidence interval 0.38 to 0.85). Those participating in the aerobic exercise programme had a 47% reduced risk and those in the resistance programme had a 40% reduced risk, compared with those in the attention group (relative risks and 95% confidence intervals: 0.53, 0.33 to 0.85; and 0.60, 0.38 to 0.97). These results were adjusted for several variables including age, body mass index, walking speed, disability and knee pain scores.

Participants who attended the most exercise sessions had the lowest risk of ADL disability. For the 28 participants who completed 78% or more of the aerobic exercise sessions, the relative risk was 0.38 (95% confidence interval 0.17 to 0.82) compared with those in the attention group. The results were similar for the 26 participants who completed 81% or more of the resistance exercise programme (0.43, 0.19 to 0.97).

Comment

This study was small so the relative risks should not be taken too literally. Nevertheless, it showed that exercise can reduce the incidence of ADL disability in older adults - with knee osteoarthritis and in the short term. Further research is needed to investigate the incidence rate in the long-term (which would include looking at whether older adults can maintain regular exercise for longer than 18 months). Participants were a selected group of patients with knee osteoarthritis (chosen because they are at high risk for ADL disability), so the results may not entirely generalise to the average population.

The preventive effect of exercise appeared to be similar for the aerobic and resistance programmes. However, further analyses examined the incidence of disability in four specific activities. Aerobic exercise was associated with a reduced risk of disability in three of the activities (bathing, dressing and transferring from a bed to a chair), whereas resistance exercise was associated with a reduced risk of disability in one activity (bathing). The lack of significance could be due to the small numbers in the analysis or it could be that aerobic exercise is more beneficial. Nevertheless, it is probable that most people, particularly older people, would choose walking as a form of exercise rather than resistance training. In any case, activities such as walking combine both aerobic exercise and a certain amount of resistance training. Swimming is another ideal activity, especially for those who suffer from joint or bone conditions.