We investigated the associations between sarcopenia definitions and their individual components and the incidence of falls based on sex differences. In men, low HGS (which represents muscle strength) and low physical performance parameters such as low SPPB score and low walking speed had an impact on a history of falls; in women, only a low ASMI (which indicates muscle mass) had an effect. The definition of sarcopenia according to the AWGS, which is characterized by low muscle strength and muscle mass, did not show a significant relationship with a history of falls in either sex group. Severe sarcopenia, defined as sarcopenia plus low physical performance, showed a significant relationship with a history of falls. These results can be explained by the different risk of falls in men and women.
The risk factors for sarcopenia are similar to those for age-related conditions [15]. Since the risk factors for falls are associated with those for sarcopenia, the correlation between falls and sarcopenia has been studied. However, the association between sarcopenia and falls is controversial. Several previous studies have evaluated of the association between sarcopenia, defined by EWGSOP diagnostic criteria, and falls. In an Italian study, Landi et al. studied the relationship between sarcopenia and the 2-year risk of falls. In a total of 250 patients aged ≥ 80 years, falls were highly prevalent among older persons with sarcopenia regardless of sex differences (OR = 3.23, 95% CI = 1.25–8.29) [16]. In another study in Chile conducted in 1,006 community-dwelling participants aged > 60 years, falls were associated with sarcopenia defined by the EWGSOP [17]. However, other studies have reported a non-significant association between sarcopenia and falls. In a Columbian study conducted in 534 participants (mean age = 74.4, SD = 8.2), falls that occurred in the previous year showed no significant relationship with sarcopenia [18]. In a previous UK study conducted in 286 participants with a mean age of 76.1 years, no significant associations were observed between sarcopenia and a history of falls [19]. Previous studies mainly defined sarcopenia based on the ESGSOP criteria; however, due to the differences in body composition between Asians and Caucasians, sarcopenia defined by the AWGS was found to be more relevant in Asians. Even with the same BMI, Asians have a higher body fat percentage, lower skeletal muscle mass, and prominent abdominal obesity than Caucasians [20]. Only one study on sarcopenia, defined by the AWGS, and falls was examined. A 2-year prospective Japanese study conducted in 162 individuals showed a significant risk of falls in the sarcopenia group in the adjusted logistic regression analysis (OR = 7.68, 95% CI = 1.41–41.77) [21]. However, this study had certain limitations—it had a small sample size, 61 of the 223 participants withdrew from the study, and the study was conducted in rural areas with a limited population.
In this study, no correlation was found between falls and the overall sarcopenia definition, but a relationship was found between falls and the sarcopenia component parameters. In men, a correlation was found between low muscle strength, low physical performance, and a history of falls. These results were similar to those reported a previous study. In a recent study conducted in Taiwan, low HGS was associated with a history of falls in both sexes [22]. Our study also showed the same results when the average HGS of fallers was compared to thar of non-fallers. However, when the cutoff value of the AWGS was set, low HGS increased the incidence of falls in men, but not in women. Although a mean difference in muscle strength was observed between the faller group and non-faller group, only men showed a significant difference when the muscle strength decreased, which was one of the criteria for diagnosing sarcopenia. In both sexes, the faller group showed lower mean SPPB and walking speed values, which indicate physical function; this finding is consistent with that reported by previous studies [23]. When compared by AWGS criteria, it is still correlated in the unadjusted logistic regression analysis. However, in women, attenuation was observed in the fully adjusted regression analysis. Low physical function is thought to be an important risk factor for falls in men; in women, other covariates have a greater effect on a history of falls.
In this study, the faller and non-faller groups showed sex differences in terms of muscle mass. In men, a significant difference was observed in ASMI between the faller group and non-faller group, but a lower ASMI was observed in the female faller group. Moreover, a significant association was observed in women in the unadjusted and fully adjusted logistic regression analyses. This is thought to be due to the sex differences in body composition [24]. Women are more strongly affected by alterations in body composition as they have a high body fat percentage and low muscle mass, which leads to the differences in physical performance and balance [25]. In a previous study, Walters et al. reported that a low ASMI was associated with balance deficit and fall incidence in women, but no association was found in men [26]. This finding is consistent with the results of our study, and the sex-related differences in body composition affect balance and the risk of falls. This difference between men and women can be explained by the difference in body composition and is more strongly associated with the lack of balance due to low physical performance in men. In contrast, the fat mass and muscle mass in women are more strongly associated with a lack of balance.
This study has several limitations. This study was cross-sectional in nature. However, this study is considered significant as it is the first large cohort study with > 2,000 participants to examine the relationship between sarcopenia, defined by the AWGS, and falls. Further prospective studies and randomized controlled studies are warranted to confirm our findings. Second, we used a self-reported questionnaire, which might have led to a possible recall bias of retrospective individual memories. If falls occur during old age, it is considered as a serious event; hence, details of the a history of falls might be accurately remembered. However, the falls possibly occurred ≥ 1 year or more before the patient developed sarcopenia. Third, 4-m walking speed was used as a physical performance parameter instead of 6-m walking speed. Because the reliability of walking speed increases with gait distance, the result could be affected [27]. Finally, since this study was conducted in older adults, which is one of the component parameters of sarcopenia, the results of physical performance tests may vary depending on the patient’s fatigue status or body condition. Hence, our results may not be considered generalizable. This problem has also been addressed in other geriatric studies.