In the description of the studies included in the systematic review and meta-analysis by Deandrea et al., care was taken to ascertain and report the gender balance within the study cohorts. (12) Cohorts with a predominance of female subjects constitute the bulk of research in terms of incidence, prevalence and risk identification. Of the 74 studies included in the meta-analysis, 20 studies consisted of female only cohorts and an additional 22 studies consisted of cohorts with greater than 60% female subjects. (12) In the analysis by Deandrea et al., male gender was protective against having one or more falls in the next 12 months. Female gender was associated with increased risk for one or more falls in all studies (OR 1.30; 95% C.I. 1.18 – 1.42), in studies that reported multivariate analyses (OR 1.28; 95% C.I. 1.06 – 1.54) and in those studies with high frequency falls ascertainment (OR 1.37; 95% C.I. 1.21 – 1.55). Female gender was associated with increased risk of recurrent falls in the next 12 months in studies that had high frequency falls outcome assessment (OR 1.34; 95% CI 1.08 – 1.68), but the association became non-significant in the studies that undertook multivariate analyses (OR 1.68; 95% CI 0.97 – 2.89). (12)
Acknowledging that gender affects the risk of falling, it is important to examine the risk predictors for falling in community dwelling older men. In reviewing studies on cohorts with a mixed population, the majority of the multivariate analyses undertaken reported adjustment for gender along with other covariates, but did not report a specific risk profile for the male subjects within the cohort. An assumption is made, therefore, that the risk factors identified in these mixed cohorts are the same for males as they are for females. As discussed above, Campbell et al. reported a difference in the association between polypharmacy and the risk of falls between genders, with the association being weaker in males. (39) Vellas et al. reported both combined and gender specific risk factor analyses in a community dwelling cohort in the
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U.S. (51) The gender specific multivariate analyses reported only slight differences in risk factors for men compared to women. In men, low physical health score was associated with increased risk of all falls (RR 1.66; 95% C.I. 1.03 – 2.69) and low mobility score associated with reduced risk of injurious falls (RR 0.25; 95% C.I. 0.10 – 0.61) compared to that seen in women.
Although Deandrea et al. included six prospective studies with male only cohorts, 3 of the published studies provided analyses based on the same cohort. (52-56) In a cohort of men recruited from Veterans’ ambulatory care clinics in the U.S., Duncan et al. examined the risk factors for one or more falls and recurrent falls in 6 months of follow-up. (55) Fall outcomes were ascertained from monthly calendar returns and phone calls to participants. In
comparison to non-fallers, fallers were significantly older, had reduced functional reach and were more likely to have a history of depression. Recurrent fallers in comparison to non- fallers were also older, had reduced functional reach and were more likely to have a history of depression. In addition, recurrent fallers, as a group, had significantly lower MMSE scores. Further analysis demonstrated an association between impaired functional reach and recurrent falls, with the strongest association seen in those with who were unable to reach at all (OR 8.07; 95% CI 2.48 – 26.2). In a further study of Veterans in the U.S., Weiner et al. examined the association between central nervous system (CNS) active medications and falls in 305 men aged 70 to 104 years. (56) In the 6 months of follow-up 33% of men fell at least once, and 28% used one CNS active medications and 10% used 2 or more CNS active medications. Once adjusted for age, cognition, depression and mobility, use of CNS active medications was significantly associated with one or more fall (one CNS mediation OR 1.54; 95% CI 1.07 – 2.22; two or more CNS active medications OR 2.37; 95% CI 1.14 – 4.94).
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The Osteoporotic Fractures in Men (MrOS) Study is a prospective cohort study of men 65 years and older recruited from 6 academic medical centres in the U.S., designed to identify risk factors for falls and fractures. Three studies examined the influence of a range of factors on the risk of falling in the cohort of 5,995 community-dwelling older men.(52-54) Fink et al. examined the relationship between Parkinson’s disease (PD) and falls in the next year. (52) A significantly greater number of subjects with PD experienced 2 or more falls (28.6%)
compared to those without PD (11.7%; p<0.0001). In the adjusted model, PD was associated with more than double the risk of multiple falls when adjusted for age and prior history of falls (OR 2.30; 95% C.I. 1.15 – 4.59), but the association was no longer significant in the fully adjusted model (OR 1.62; 95% C.I. 0.77 – 3.38). Cawthon et al. examined the
relationship between alcohol intake and falls in the next year in the same cohort. (53) The 4 question CAGE questionnaire was administered to define a history of problem drinking., with an answer of “yes” to 2 or more questions indicating problem drinking. (57) Light alcohol intake was associated with reduced risk of recurrent falls in the multivariate analysis (RR 0.77; 95% C.I. 0.65 – 0.92), but a history of problem drinking was associated with increased risk of falls (RR 1.59; 95% C.I. 1.30 – 1.94) as was a history of heavy drinking (drinking >5 drinks most days) (RR 1.43; 95% C.I. 1.16 – 1.76). In the same cohort, Orwoll et al.
examined the association between testosterone, physical performance measures and falls in the MrOS cohort. (54) A history of falling at least once in the preceding 12 months was associated with increased risk of falling in the follow-up period (RR 2.63; 95% C.I. 2.29 – 3.03). Age was also strongly associated with risk of falling, with increased incidence of falls (0.6 falls per year in 65-69 years versus 1.0 falls per year in ≥80 years) and age was
associated with increased frequency of falls. Measures of poor physical performance were also associated with falls risk. Subjects with grip strength in the lowest quartile or who could not perform the test, had a 40% increased risk of falling compared to those in the highest
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quartile of grip strength (RR 1.7; 95% C.I. 1.4 – 2.1). Reduced leg power, and inability to perform the narrow walk test were both associated with increase in falls risk. Testosterone level did have an association with increased risk of falling, but the association was strongest in the youngest sub-group of men, with the association weakening with increasing age (65-69 years RR 1.8; 95% C.I. 1.2 – 2.7; versus ≥80 years RR 1.15; 95% C.I. 0.7 – 1.8). In all men, the association with increased risk of falling was strongest in the lowest quartile of
testosterone level and remained significant even when adjusted for multiple confounders, such as the physical parameters previously described (RR 1.40; 95% C.I. 1.17 – 1.67).
An additional cross-sectional study in the United Kingdom examined the association between prior falls history, fear of falling and other health status and demographic characteristics in a group of older men recruited from primary care. (58) Men were asked to wear an
accelerometer for 7 days to map their physical activity. Those who had experienced recurrent falls in the previous year had lower daily activity levels as measured by fewer steps per day (942 steps; 95% C.I. 503 – 1381), less minutes in light (12 minutes; 95% C.I. 2 –22) and moderate to vigorous activity (10 minutes; 95% C.I. 5 – 15) and more minutes in sedentary activity (22 minutes; 95% C.I. 9 – 35). The reduction in physical activity was even more pronounced in those with fear of falling; 1766 fewer steps per day (95% C.I. 1391 – 2142), 27 minutes less in light activity (95% C.I. 13 – 22), 18 minutes less in moderate to vigorous activity (95% C.I. 13 – 22) and 45 minutes more sedentary activity (95% C.I. 34 – 56), than those who did not fear falling. When adjusted for history of falls, exercise outcome
expectations, exercise self-efficacy, number of days leaving the house, mobility limitations, fear of falling, depression and quality of life, these associations were no longer significant either for one fall, or 2 or more falls.
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There remains a gap in the knowledge about the baseline risk predictors for falls in community dwelling older men, and how much of the previous assumptions about similar risk factors for future falls between the sexes holds true. Female sex is associated with greater risk of falling and many studies adjust for sex, even if a significant association between sex and falls is not demonstrated in their cohort. Females make up the majority of subjects in cohort studies examining the risk of falls, and may have a greater influence on the association between risk factors and falls in mixed gender cohorts.
In male-only cohorts a question arises about the representativeness of the cohorts. Two of the prospective cohort studies on male cohorts were Veterans’ studies and the MrOS study is a volunteer study, which influences the representativeness of these samples. In addition, the MrOS study was designed to understand the risk of osteoporosis in men and therefore has reported the risk of falling in terms of known risk factors for low bone mineral density. As far as we are aware, there has not been a prospective cohort study that has looked at the risk factors for falls in a large, representative sample of community-dwelling older men.
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