Falls associated with indoor and outdoor environmental hazards among community-dwelling older adults between men and women

Falls among older adults have received considerable attention as a major public health concern in the United States. Approximately one-fourth of community-dwelling adults aged 65 years or older in the United States experience falls each year [1]. Among those who fall, one-third suffer serious injury, including hip fractures and traumatic brain injury that may require hospitalization [2]. Injuries from falls were shown to result in various individual health and behavior outcomes, including functional decline, loss of independence, fear of falling, and social isolation [3].

Falls among older adults are a result of complex factors, involving individual and environmental circumstances [4, 5]. Individual factors for risk of falling include sociodemographic, health, and behavioral characteristics. For example, older adults who have functional limitations, muscle weakness, comorbidities, anxiety, and lack of physical activity tend to be exposed to the risk of falling [6]. Environmental factors refer to all attributes that are external to the human host, which include slippery or uneven surface, obstacles, stairs, abrupt vertical transitions, and weather condition [7]. These individual and environmental factors are known to be independently associated with the occurrence of falls [8].

In terms of individual risk factors for falls, gender is frequently reported as a risk factor of falling [9]. The majority of studies reported higher rates of falling in women than men [10, 11]. These gender disparities in fall are known to be associated with differences in a wide range of health, behavioral, and psychosocial factors. For example, women reported poor self-rated health conditions, vision impairment, and deterioration in muscle and bone mass, which makes females more vulnerable to risks of falling [12]. Other gender differences in risk factors for falling include sleep deprivation [13], diabetes [14], and vitamin D deficiency [15]. In addition, perceptions about falling may be different by gender. Men tend to underreport their challenges related to falling and report higher self-efficacy related to falls, compared to women. Men were also more likely to be reluctant to admit having a fear of falling, compared to women [16].

Several studies have identified the importance of the home settings and neighborhood environments for individual health and well-being of older adults [17]. Most older adults prefer to age in place in their homes and neighborhoods. As people age with reduced mobility and functional loss, they tend to spend more time in the home and in their communities. Especially for community-dwelling older adults, they could be directly and indirectly influenced by home and neighborhood environments that include barriers and problems or lack supportive features. Common barriers in the home environment include poor flooring conditions, poorly designed tubs, badly arranged furniture, inadequate lighting, and obstructed walkways, all of which potentially increase fall risks [18].

Besides the environmental barriers in the home, several outdoor environment features in the neighborhood including bumpy walking surfaces, steep curb ramps, and poorly maintained street conditions have been identified as barriers that limit activity [19]. For example, older adults who reported poorly maintained street conditions in their neighborhoods have more activity limitations, while those living in areas with better public transportation and accessible parks have less activity limitations [20]. Relatively limited studies, have identified the neighborhood environment as a risk factor of falls. Uneven surfaces on streets have also been reported as a risk factor of falls [21, 22]. Qualitative studies showed that older individuals reported uneven walking surfaces, inadequate maintenance, poor lighting, and traffic patterns as perceived risk factors [23].

Another line of research has classified fall risk factors into those that can cause indoor and outdoor falls. Previous studies have shown that older adults at high risk for outdoor falls were different from those at high risk for indoor falls [24]. Indoor falls tended to occur among frail individuals while outdoor falls were more likely to occur among more active people with healthier characteristics. Specifically, Kelsey et al. [25] found that older participants with poor baseline health characteristics had elevated rates of indoor falls while healthy and younger older adults had elevated rates of outdoor falls. Previous studies also showed different consequences of indoor and outdoor falls [26]. Mänty, Heinonen [27] found that indoor falls were associated with future mobility limitations in Finnish women while outdoor falls were not.

The circumstances surrounding indoor and outdoor falls may also differ by age and gender. Compared to outdoor fallers, indoor fallers were more likely to be women and older [28]. In the location-specific analyses, women reported higher fall rates in the kitchen while performing household activities, but there were no gender differences in their rates of outdoor falls (Duckham et al., 2013). Although the exact mechanism of why there were gender differences in the likelihood of falls is still unclear, men and women differ in their time spent indoors and outdoors, which could potentially result in different fall tendencies in different locations [29]. For example, older women are more likely to spend time doing housework inside the home compared to older men [30]. Although men have tended to spend more time inside the home and have tended to do more housework after retirement in recent years [31], the types of household labor are still unequal between older men and women. Specifically, older women are typically responsible for routine and repetitive tasks such washing dishes, preparing meals, and cleaning the house inside the house while men engage in more occasional tasks, such as household repairs, yard work, and vehicle maintenance, which is done more outside the house [32]. These differences should be considered when developing prevention programs and environmental interventions for falls.

Although numerous studies have identified risk factors of falling and even environmental risk factors for falls, few studies have comprehensively examined how indoor and outdoor environmental hazards are associated with increased falls simultaneously. Additionally, no study has been conducted to understand such relationship across genders. To address these concerns, we analyzed the prevalence of falls in relation to the environmental hazards inside home and outside home environments among community-dwelling individuals aged 65 or older by gender. Since women and men have different activities and social roles within the home and neighboring areas, we hypothesized that the men’s and women’s prevalence of falls were differently associated with environmental factors in locations. The present study contributes to the literature by improving our understanding of environmental risk factors for falls by gender. The findings will be useful for creating tailored and optimal fall prevention strategies for both male and female older adults.

Gender differences in falls have been reported in many previous studies of older adults. However, environmental hazards associated with falls by gender are not well understood. The purpose of this study was to examine the gender differences in the associations of indoor and outdoor environmental hazards with the odds of falls. We found that indoor environmental hazards were more likely to influence the odds of falls among women while outdoor environmental hazards were more important factors influencing falls among men. Although we were unable to capture where falls occurred across gender, this study comprehensively incorporated each indoor and outdoor environmental hazards variable in the study. To the best of our knowledge, this study provides the first gender-specific prevalence of falls in relation to the indoor and outdoor environmental attributes. This study contributes to the literature on gender differences in the associations between falls and environmental hazards among older adults.

Our results confirm previous findings that older men were less likely to fall than older women [36]. Such gender disparities in fall incidence might reflect the differences in underlying sociodemographic, health, and behavioral factors. We found that individual health conditions were more associated with falls in women than in men. For example, poor self-rated health status, depression, medication use, and frequency of going outside were significantly associated with falls in women but not in men after adjusted for all variables, which was also similar findings reported by other studies [13]. Such symptoms were known to influence different lifestyles, physical activities, and living arrangement, which may result in the risk of falls in women especially while staying at home [37].

Gender-specific analysis in our study indicated that there were gender differences in the relationship between the environmental hazards and falls. On one hand, the finding showed that indoor environment was significantly associated with elevated falls for women, implying that older women may experience falls due to the complex factors between individual factors and indoor environmental hazards. This may be because compared to older men, older women tend to have more individual health problems with age and spend more time inside the home doing household activities. Previous studies have also supported that older women frequently experienced falls in the kitchen while preparing meals and washing dishes [38]. For men, indoor environmental hazards were not associated with falls, but outdoor environmental hazards were found to be an important predictor of the odds of experiencing falls even after adjusting for individual factors. This implies that older men are more likely to be influenced by outside home environments, such as problems with an uneven pavement as they walk home, for example. It may be because compared to women, men not only tend to go outside more frequently and do outdoor activities, but they may be less likely to pay attention to the areas in front of and around the home, such as the garden, access path, and neighborhood streets. This result was identified when looking at the presence of an interaction term between environmental factors and gender. We found a significant interaction between gender and outdoor environmental hazard in this study, indicating that the presence of outdoor environmental hazards increased the risks of falling in men but marginally decreased the risks of falling in women shown in Fig. 2. It is not clear if women may not go outside due to increased outdoor environmental hazards, but previous studies have reported that women were more likely to restrict their outdoor physical activity due to fear of falling outside, compared to men [39]. This result suggests that increased outdoor environmental hazards may block the possibility of falling outside among older women or rather increase their falls influenced by indoor environmental hazards, which may warrant further investigation.

Despite the importance of general home modification and maintenance of street conditions in preventing falls, few solid methods are available to evaluate fall-related environmental hazards in different locations, which makes it difficult to determine which environmental factors from the home to the neighborhood boundary could influence fall incidents. In the present study, we were able to consider the environmental hazards in different locations (i.e., indoor environment- inside the home and outdoor environment- in front of and around the home). However, we were unable to capture various environmental hazards and barriers for older fallers in the study. For example, path conditions, change in level, and obstructions around the home and even neighborhood environments were missing in our study. Although our study would contribute to the understanding of environmental factors causing falls by using limited variables, further study will need to develop comprehensive indoor and outdoor environmental checklist and incorporate life-space mobility, a concept for assessing spatial patterns of the mobility of older adults [40], to understand where a person experiences falls from the home environment to the neighborhood environment.

The strengths of this study include examining the use of multiple environmental hazards in both indoor and outdoor locations and how the hazards impact falls in older adults by gender. Most previous studies have exclusively focused on either indoor or outdoor environments, but this study enhances our understanding of environmental contributions to the risk of falling by considering indoor and outdoor environments simultaneously. In addition, this study used data from a large population-based sample of community-dwelling older adults, which helps increase the generalizability of the results. Although the number of environmental variables captured in this study were limited, the variables were relatively objective given that they were measured by an interviewer using an environmental checklist.

This study has several limitations. First, this study was based on a cross-sectional design with relatively old but baseline data which limits our ability to determine causal relations of the environment on falls across genders. Due to some missing items and selection bias due to loss to follow-up in the latest assessment dates, we decided to test indoor and outdoor environmental hazards associated with falls by gender by using baseline data although it is unclear if there is no obvious change in behavior and environmental hazards over 10 years. Further research should will consider the prospective relationship between environmental hazards and falling. Second, there were no data on where the reported falls occurred (e.g., kitchen, living room, yards, streets, or parks), which does not allow us to explain the exact mechanism of the characteristics of falls by location as well as by gender. It would be helpful to collect information about the locations of falls and the activities of the older adults when they fell in a future study. Third, we measured each built environmental hazard by indoor and outdoor, but the built environments, especially outdoor environments, are highly influenced by neighborhood socioeconomic status and quality, which was not considered in our study. We also acknowledge that this study only considered the negative environmental characteristics potentially causing risk of falling but a further study should consider the positive environmental characteristics that can help prevent falls and promote each safe indoor and outdoor activities, such as grab bars and handrails inside the home and quality of trees and maintenance of street conditions outside the home. Another limitation is that we were unable to capture how much time each participant spent in different locations although this study included a variable of frequency of going outside (days per a week) as a proxy variable for the time spent outdoors. Future studies should collect detailed information of frequency of time spent and types of activities in different locations to further understand the differences in fall incidents among men and women in responding to different built environments. Finally, further study needs to include the perceived environmental characteristics because it is reasonable to expect that the same physical environment may be perceived differently by different participants.

Any older adult can experience falls at home settings and near their home. This study revealed gender differences in environmental risk factors for falls. The presence of indoor environmental hazards was an indicator of the fall risk for women but not for men while the presence of outdoor environmental hazards was an indicator of the fall risk for men but not for women. Although the present study was unable to capture where falls occur, this study can help us understand how indoor and outdoor environment could differently influence falls across gender groups. Understanding these differences and gathering information about the different risk factors across genders could help improve healthy aging promotion programs and develop effective interventions to mitigate the risks of falling among community-dwelling older adults across genders.