We identified the incidence rate and multidimensional falls risk predictors at 18-month follow-up among 1763 community-dwelling older Malaysians in the present study. The incidence rate of occasional and recurrent falls observed in our present study was 8.47 and 3.21 per 100 person-years respectively, with no increase with age. Falls prevalence of 15–18% [16, 17] and 27% over a six-month follow-up period [18] had previously been reported among community-dwelling older Malaysians. The prevalence of recurrent falls has been reported as 8.3% [19].
Despite the apparent association between age and decline in both physical and cognitive functions [20], our results showed that advancing age did not predict the incidence of occasional and recurrent falls. In an age-specific population, the incidence of falls was not age-dependent, as opposed to the prevalence of falls, which was reported to be age-dependent [21]. In other words, while the number of cases of falls does not increase with increasing age, cumulatively, the number of individuals who would have fallen within the older population over any given period would be observed due to the consistent addition of new cases.
Occasional falls could be accidental and are usually associated with extrinsic factors [22, 23]. In comparison, recurrent falls among older adults are usually related to multifactorial intrinsic factors and are usually associated with a more complex risk profile model. However, our current findings showed that the identified predictors for both occasional and recurrent falls were similar, with the exception of being single was a predictor of occasional falls while having a history of stroke and higher percentage body fat were identified as predictors of recurrent falls. Having a higher depression scale score, lower hemoglobin levels, and taking longer to complete the chair stand test appeared as robust predictors of both occasional and recurrent falls in community-dwelling older adults.
Depression has been shown to be associated with both occasional and recurrent falls among community-dwelling older adults previously [24, 25]. Depressive symptoms may affect the older adult’s mobility and executive function [26]. The causal relationship between depression and falls was not fully explained by adjustment for the medical comorbidities, nutritional, physical and laboratory factors. The use of medications was not adjusted for within this study, which may account for the increased risk of falls among individuals with symptoms of depression [27]. Depression in older adults has been attributed to structural brain changes that interfere with cortical-subcortical circuits, basal-ganglia, and limbic networks, which in turn affect postural stability leading to the occurrence of falls [27]. Furthermore, antidepressants have been associated with single and recurrent falls [28, 29]. The proposed mechanisms for the antidepressant related falls include orthostatic hypotension, dizziness, compromised vision and mental confusion [29].
Lower hemoglobin levels increased the risk of both occasional and recurrent falls. Potential mechanisms linking the age-associated decline in hemoglobin and falls include fatigue, reduced muscle strength and muscle quality. The decline in oxygen delivery is attributed to the reduction of hemoglobin levels, whereby hemoglobin functions as an oxygen carrier to skeletal muscles, leading to a reduction in muscle function and declining mobility. This finding was in agreement with the three-year Longitudinal Aging Study Amsterdam demonstrating frequent episodes of falls among older adults with anemia as compared to their non-anemic counterparts [30]. Low hemoglobin levels were also shown to increase the risk of recurrent falls among the U.S. population, aged 45 years and above [31]. The presence of lower hemoglobin may also reflect underlying nutritional deficiencies or chronic conditions affecting hemoglobin production. Others include undetected causes of hemoglobin loss due to medical conditions such as peptic ulcer disease or malignancy and medications, including ulcer-inducing drugs and those that inhibit marrow function. However, these factors had not been fully accounted for within this study.
The chair stand test, a measure of lower extremity muscle strength, has been demonstrated to be beneficial in determining fall risk [32]. Older adults who were unable to perform the chair stand test were reported to be associated with a higher risk of fall-related injuries [33]. Moreover, lower extremity weakness was reported to increase the odds of occasional and recurrent falls in older adults [34] since it was associated with abnormal gait, loss of balance, declined mobility, flexibility and functional performance [35]. Besides, strengthening of lower limb muscles has been reported to be effective in preventing falls in older adults [35]. Similarly, we have demonstrated that muscle strength was associated with falls among Malaysian community-dwelling older adults in our earlier pooled data findings [36].
Our study results also showed that the risk of recurrent falls at 18 months was increased among older adults with higher percentage body fat. One of the probable reasons for the existence of a relationship between higher percentage body fat and increased risk of falls could be due to declined lower extremity muscle strength following excess adiposity, which could affect postural stability and balance [37]. Excess adipose tissue accumulation may also lead to dynapenic obesity, a condition linked to a decline in muscle strength, loss of muscle mass, and sarcopenic obesity [38, 39]. As a result, it may lead to impaired mobility and balance and consequently, increase fall risk in older adults. In an observational study involving 164,737 participants between the ages of 19 to 106 years, older adults with obesity had the odd ratio of 1.10 and 1.12 for one fall and two or more episodes of falls respectively [40].
Increased body fat predisposes individuals to underlying medical conditions such as diabetes, hypertension, heart disease, stroke and osteoarthritis and may also be an indicator of reduced physical activity. Recent studies have also linked adiposity with low-grade inflammation, which not only predisposes individuals to osteoarthritis and dementia but also increases the risk of sarcopenia and osteoporosis [41]. Further, stroke also has been identified as one of the major risk factors of falls and recurrent falls [42]. Stroke survivors also tend to develop a fear of falls, which is associated with physical and functional decline, decreased quality of life, impaired social interaction, depression and anxiety [43, 44]. Previously, having depressive symptoms and loss of dynamic balance has been demonstrated to increase the risk of falls among stroke survivors [45, 46].
Lastly, being single (unmarried) was a risk factor of occasional falls during the 18th-month follow-up in this current longitudinal study. Single older adults were often associated with living alone, having loneliness, depressive symptoms, and poor health [47, 48]. All of these characteristics were also associated with increased risk of falls in older adults. In addition, older adults living alone were reported to have a higher risk of declined physical fitness due to limited participation in physical activity with higher possibilities of fall-related injuries and elevated risk of mortality and morbidity [49, 50].