A high incidence of falls and related injuries is seen in people with intellectual disabilities (ID) (Cox et al., 2010, Enkelaar et al., 2013b, Hale et al., 2007, Hsieh et al., 2012 and Sherrard et al., 2001). Falling is not restricted to the elderly in the population of ID (Sherrard et al., 2001), but fall risk does increase with advancing age (Chiba et al., 2009, Cox et al., 2010, Hsieh et al., 2001 and Willgoss et al., 2010).
A number of personal and medical characteristics can lead to an increased fall risk. In people with ID, older age, being female, more severe level of ID, impaired mobility, physically active, back pain, arthritis, fracture history, cerebral palsy, good visuo-motor capacity, good attentional focus, urinary incontinence, heart condition, epilepsy, visual impairments, polypharmacy, and behavioral problems have been mentioned as possible risk factors for falls (Cox et al., 2010, Enkelaar et al., 2013b and Finlayson et al., 2010Hsieh et al., 2012 and Willgoss et al., 2010). Having Down syndrome (DS) was found to reduce the risk for falls and related injury (Finlayson et al., 2010).
Next to personal and medical characteristics, physical fitness may be an important aspect for falls in people with ID. Older adults with ID have poor balance, strength, muscular endurance, and slow gait speed (Hilgenkamp et al., 2012b and Oppewal et al., 2013). In the general population, these physical fitness components are well-established risk factors for falls (American Geriatrics Society et al., 2001, Close et al., 2005, Deandrea et al., 2010, Muraki et al., 2013, Quach et al., 2011, Stenhagen et al., 2013 and Tinetti and Kumar, 2010). However, results from prospective studies performed in the general population may not apply to older adults with ID. The predictive value of physical fitness for falls in the general population is related to an age-related decrease in physical fitness or due to diseases. This relationship may be confounded by the lifelong cognitive impairment of people with ID. This lifelong cognitive impairment may negatively influence their motor development since childhood, which may negatively influence their balance, strength, endurance, and gait throughout their life, and not just at an older age. This line of thinking is supported by the finding that motor and cognitive functioning are fundamentally interrelated, with similar developmental trajectories and the use of similar brain structures (Diamond, 2000). Impairments in physical fitness may not necessarily be related to an increased fall risk in the same amount as in the general population because people with ID may have developed different compensation strategies and utilize them over their entire lifespan. For example, people with DS show more variability in gait than people with normal intelligence, but they use this variability functionally to optimize their movement. This implies the use of different control strategies to compensate for their limitations (Black et al., 2007 and Smith et al., 2011). Based on this hypothesis, the correlation between a decrease in physical fitness and falls may be less strong.
A recent prospective study investigating risk factors for falling in older adults with mild to moderate ID did not find balance and gait speed to differ between fallers and non-fallers. However, adults who fell indoors, performed worse on balance and gait tests (Enkelaar et al., 2013b). In contrast, retrospective studies did find strength and gait impairments to be associated with an increased fall risk in people with ID (Chiba et al., 2009, Hale et al., 2007 and Hsieh et al., 2012). More knowledge is needed to identify the predictive value of the physical fitness in predicting fall risk. This will help to identify people at risk and thereby the decision-making for treatment.
The aim of this study was to assess the predictive value of balance, gait speed, strength, and muscular endurance for falls, over a 3-year period, in a large sample of older adults with ID.
