In this large cohort study, we investigated the independent effects of anxiety symptoms and depressive symptoms on fear of falling and activity restriction using a nationally representative sample of older adults in the United States. We found that (1) 10% and 13% of participants at T1 reported experiencing symptoms of anxiety or depression, and approximately 20% and 11% reported “Had fear of falling but not activity restriction” or “Had activity restriction” at T2, respectively; (2) anxiety symptoms were associated with a higher risk ratio of “Had fear of falling but not activity restriction” and “Had activity restriction” one year later adjusting for depressive symptoms; and (3) depressive symptoms did not seem to have any association with fear of falling and activity restriction.
Consistent with previous studies (12, 34), our results showed that anxiety symptoms increased the risk of future fear of falling. The reason could be that fear and anxiety symptoms are similar as they are the basis of anxiety disorders (35) and the presence of anxiety symptoms could be the driving factor of fear of falling (34). Moreover, we found that anxiety symptoms remained a significant independent factor that is associated with “Had fear of falling but not activity restriction” even after controlling for depressive symptoms. More specifically, participants with anxiety symptoms were 1.33 times more likely to develop fear of falling in the following year compared to those without anxiety symptoms. This result was consistent with Payette et al’s study (27), a pilot study that concluded the significant relationship between anxiety symptoms and fear of falling while controlling for depressive symptoms, fall risk, and sociodemographic variables. Payette’s study was a small, pilot study (N = 25) with a high proportion of women (88%). However, we can say that the results of our study can be better interpreted and generalizable because of the large sample size and a more balanced female proportion (58.1%) (27).
We also found that anxiety symptoms increased the risk of future activity restriction independently. This result also supported the previous studies (25, 26). For example, Hull and colleagues found that anxiety symptoms measured by the Geriatric Anxiety Inventory were a significant factor of fall-related outcome expectancy in a sample of 205 community-dwelling older adults, and activity restriction was a component of this outcome index (25). Painter and colleagues found anxiety symptoms assessed by the Hamilton Anxiety Scale could predict activity restriction through the indirect influence of fear of falling rather than directly among 99 community-dwelling older adults (26). Though these studies found a significant association between anxiety symptoms and activity restriction, it should be noted that they failed to establish a direct, independent, and longitudinal association. First, they did not use activity restriction as a direct target outcome but measured it via other variables such as fear of falling. Second, they did not control for depressive symptoms. Third, the longitudinal association could not be established due to their cross-sectional study design. Our study not only provided evidence of whether anxiety symptoms were directly and independently related to activity restriction, but presented the significant longitudinal effects of anxiety symptoms for future fall worry levels. Therefore, our results underscored the importance of screening older adults with anxiety symptoms to prevent future development of fear of falling and activity restriction, as well as related adverse health outcomes.
Our results showed that depressive symptoms had no significant associations with fear of falling and activity restriction in the fully adjusted model. This result was a surprise because previous studies showed opposite results (24). For example, Namkee and colleagues found “onset of depression” (no depression at baseline but depression one year later) and “continued depression” (had depression at baseline and continued at one year later) were significantly associated with greater odds of activity restriction at one year after the baseline (30). We speculated that the significant correlation in this study was because both “onset of depression” and “continued depression” were more focused on the concurrent relationship between depressive symptoms and activity restriction, as opposed to our focus on the longitudinal association between depressive symptoms at baseline and activity restriction one year later. Please be noted that depressive symptoms in our study were measured via PHQ-2 which may have lower acceptable accuracy for screening for depression compared to other tools (36) (e.g., PHQ-9) commonly used in studies investigating the association between depressive symptoms and fall-related outcomes. This could also explain the opposite results.
The different results of the association between depressive symptoms and activity restriction with or without controlling for anxiety symptoms should be highlighted. Taking anxiety symptoms into account, the association between depressive symptoms and activity restriction became insignificant, suggesting anxiety symptoms may weaken the effects of depressive symptoms on activity restriction. Therefore, further investigations are needed to clarify the role of anxiety symptoms on the pathway from depressive symptoms to activity restriction and determine its effect size.
Our findings provided some evidence that anxiety symptoms may be able to predict future levels of fear of falling and activity restriction. This finding has implications for guiding the strategies for preventing fear of falling and activity restriction among older adults from the context of tertiary prevention. First, the knowledge of the scientific relationship of anxiety symptoms and future levels of fear of falling and activity restriction should be shared with and disseminated to the public so that the public, especially older adults and their caregivers, can be aware that anxiety symptoms affect future fear of falling and activity restriction levels, and subsequently may lead to more adverse health outcomes such as falls and functional impairment. Second, it is recommended that anxiety symptoms should be screened for early detection and diagnosis. Then we can identify and treat older adults with a high risk of developing fear of falling and activity restriction better as secondary prevention. Moreover, the assessment tool used in this study (GAD-2) is readily available and easy to use in the community (12) and therefore, may benefit the public. Finally, older adults who already have been evaluated for anxiety symptoms should receive timely and effective targeted interventions. On the other hand, the issue of the high comorbidity of anxiety symptoms and depressive symptoms can not be ignored. Using multiple years of follow-up measurements, as well as different measurement tools, further investigations are needed to examine the effect size of anxiety symptoms and depressive symptoms.
The strengths of this study include its longitudinal design and a large nationally representative sample of the study population. However, several study limitations should be noted. Selected variables were all based on retrospective self-reported interviews. Recall bias may influence the accuracy of the data and may have caused a lack of significant associations between depressive symptoms with fear of falling and activity restriction. The GAD-2 and PHQ-2 were used to measure participants’ anxiety symptoms and depressive symptoms respectively. These tools were originally developed for not diagnostic but screening purposes. Therefore, the data may be limited to the state of emotion at the time of the interview only.