Abstract
Background:
Older adults with visual impairments experience a higher risk of falling, and are more vulnerable to adverse health consequences associated with falls than those with normal vision. This study characterizes longitudinal changes in objectively measured physical activity and fear of falling (FoF) occurring after various types of falls in visually impaired older adults.
Design:
Prospective cohort study.
Setting:
Hospital-based enrollment.
Participants:
People with glaucoma or suspected glaucoma.
Measurements:
Falls were defined as unintentionally coming to rest on the ground or a lower level, and injurious falls were determined though follow-up calls. Study participants were categorized into three groups–fallers with injurious consequences, fallers without injurious consequences, and non-fallers based on fall status in the first year. Physical activity was assessed by waist-bound accelerometer. FoF was evaluated by questionnaire, with Rasch modeling generating FoF scores where higher scores reflected worse FoF. The three-year longitudinal changes of physical activity and FoF were modeled using mixed-effects models.
Results:
In linear models fully adjusted for visual field damage and other covariates, physical activity among injurious fallers showed greater annual (per year) declines in daily steps (−425 steps/day, 95% confidence interval [CI]: −793, −57), daily active minutes (−13 minutes/day, 95% CI: −21, −6), and daily moderate and vigorous physical activity (MVPA) minutes (−3 MVPA minutes/day, 95% CI: −5, 0) over the three-year period as compared to non-fallers; however, physical activity did not significantly decline among non-injurious fallers. No longitudinal increases in FoF scores were observed in injurious or non-injurious fallers when compared to non-fallers.
Conclusion:
Among visually impaired older adults, injurious falls identified prospectively over 12 months contributed to a significant decline in physical activity over a three-year period, while minimal changes were observed in FoF.
Keywords: activity, injury, mobility, falls, vision impairment
Introduction
Falls are the leading cause of morbidity among older adults worldwide.1 More than 30% of community-dwelling adults aged 65 years or older fall at least once each year and half of these falls lead to some form of injury, including fractures, activity limitations, less social engagement and poorer quality of life.2–5 Older adults with reduced vision have a two-fold (or higher) risk of injurious and non-injurious falls compared to older adults without vision loss.6–9 Understanding the long-term impact of injurious and non-injurious falls is important for understanding the potential adverse outcomes resulting from falls among visually impaired older adults.
One potential downstream consequence of a fall is the restriction of physical activity, but surprisingly little work has quantitatively assessed declines in physical activity after falls. Physical activity is important to preserve after a fall given that it is a strong determinant of overall health,10,11 and less active individuals demonstrate compromise in physical functioning,12 cognitive performance declines,13 and a higher risk of losing physical independence.14 Previous cross-sectional and prospective studies have noted that those who have recently fallen are at high risk for decline in self-reported physical activity,15 and those who engage less physical activity are more likely to experience recurrent falls.16,17 However, the literature quantitatively measuring the magnitude of decline in physical activity after injurious or non-injurious falls is lacking. Indeed, previous research evaluating physical activity after falls has assessed physical activity using self-reported questionnaires,16–19 which is subject to measurement error20,21 and less associated with objective health biomarkers than activity quantified objectively by wearable technology;22,23 these devices allow measurements of daily activity intensity and duration that are often overlooked using subjective questionnaires.24 Moreover, the retrospective assessment of self-reported falls is subject to recall bias, such that, those who recall their falls are more likely to sustain injuries, while less intense falls may be forgotten.25
Another potential downstream consequence of a fall is the psychological component;26–30 however, little research has approached this relationship rigorously and quantitatively by evaluating fear of falling (FoF) levels over time, and comparing changes in fallers and non-fallers. FoF often contributes to a low perceived ability to avoid falls and/or loss of confidence in daily activities, thus becoming a driver of activity restriction.31 Visually impaired persons with greater FoF are less physically active than those with less FoF.30 Additionally, older adults with greater FoF are more likely to reduce travel outside the home, have less frequent social interaction, and transit to assisted living.29,32–34 Previous studies have noted cross-sectional associations between a self-reported fall and FoF,35 and those reporting multiple or injurious falls are more likely to report FoF,28 but the impact of injurious and non-injurious falls on long-term changes in FoF, measured quantitatively along a continuous scale, is not well understood.
Using data from Falls in Glaucoma Study (FIGS), a prospective cohort study, we sought to characterize the longitudinal changes in objectively measured physical activity and FoF related to different types of falls (i.e. injurious vs. non-injurious) in a sample of visually impaired older adults. We hypothesized that participants who experienced either injurious or non-injurious falls in the initial one-year study period would demonstrate a greater decline in physical activity and increase in FoF over the full three-year observational period as compared to their counterparts who did not fall. Our findings can be used to guide therapies to prevent the deleterious consequences of falls, particularly for eye diseases (e.g., glaucoma) where there is no restorative therapy.
Methods
Participants
Study participants were recruited from a single-center cohort study, known as FIGS, conducted at the Johns Hopkins Wilmer Eye Institute from 2013 to 2015. Participants were eligible if they were: aged 60 or older, lived within 60 miles of hospital, diagnosed with primary/suspected glaucoma, and were able to conduct visual field testing. Detailed eligibility criteria are described in prior publications.36. All participants provided written consent.
We compared the characteristics of participants to the study-eligible population (258 patients) visiting the same hospital over a one-week period. Recruited participants were more likely to report falling within the last year compared to general study-eligible population.
Assessment of falls and injurious falls
Falls were defined for study participants as unintentionally coming to rest on the ground or a lower level, and further explained to participants using an instructional video.30,37 Participants were given falls calendars to begin using after their baseline assessment, and were asked to mark calendars daily to indicate whether a fall occurred or not. Subjects returned calendars monthly. Injurious falls were distinguished from non-injurious falls via follow-up calls initiated after falls were reported by participants. An injurious fall was judged by the presence of one or more of the following: pain, bruising, swelling, pulled muscle, sprained ligament, joint dislocation, or fracture.38 For this analysis, study participants were categorized into three groups – fallers with injurious consequences (injurious fallers), fallers without injurious consequences (non-injurious fallers), and non-fallers based on fall calendar data from the first year. Persons reporting one or multiple falls in the first study year were categorized as injurious fallers if any of the falls indicated an injury. None of the falls occurring in the first year had missing injury data.
Evaluation of physical activity and fear of falling
Physical activity was assessed at four annual intervals (baseline and each annual follow-up visit) using a waist-bound accelerometer (Actical, Respironics Inc., Murrysville, PA). Participants wore the accelerometer for seven-days annually and average daily activity was estimated to infer the amount of physical activity for that year. People were instructed to wear the accelerometer during all waking hours except when bathing or swimming. We restricted our analyses to time points in which at least four days of valid accelerometer data were available for analysis.39 Valid accelerometer data were used for participants who wore the device for at least eight hours per day. Steps during each one-minute interval were quantified by the accelerometer, which recorded activity in one-minute epochs for up to 7 days annually over the study period. The intensity of motion during one-minute period was quantified as “counts”, an arbitrary unit transformed from total acceleration. The count data were used to classify physical activity level for each minute as sedentary, light, moderate or vigorous using the thresholds defined by Colley and Tremblay.40 Daily moderate and vigorous physical activity (MVPA) minutes were calculated as the sum of moderate and vigorous active minutes, and daily active minutes were identified as the sum of light and MVPA minutes.
FoF was also assessed four times (baseline and each annual follow-up visit) by the University of Illinois at Chicago FoF Questionnaire.41 The 18 different tasks queried from easy activities (such as getting out of a car) to hard activities (such as walking on icy ground). For each task, participants selected one of three responses to indicate if they were “very worried”, “moderate or a little worried” or “not worried” about falling when performing given activity. We then applied Rasch models to match personal ability (i.e., person measure scores) to task difficulty (i.e., item measure scores) on the same linear scale using MPlus Version 7.0.42,43 Both person measure and item measure scores were expressed in log-odds (logit) units.42 Lower FoF scores reflected less FoF and higher scores reflected greater FoF. To obtain all FoF scores from the same Rasch model, we anchored FoF scores in follow-up visits to the baseline FoF score for each participant.
Visual assessment and characterization of covariates
Visual function was evaluated through visual acuity testing (ETDRS chart) and visual field testing (Humphrey HFA-2 perimeter [Carl Zeiss Meditec, Carlsbad, California, USA]). Integrated VF (IVF) sensitivity was derived by combing pointwise sensitivities from each eye to create a sensitivity at each spatial coordinate through the maximum sensitivity approach.36 Next, we converted the decibel sensitivity values in the IVF to raw sensitivity values, then averaged all points in the full visual field, and retransformed average raw sensitivity back to decibel values to derive mean IVF sensitivity values. The average IVF in people with normal VFs was in the range of ≥31 dB, while <31 dB indicated visual field damage. The severity of visual field damage was further classified as following: normal/mild (IVF >28 dB), moderate (IVF 23–28 dB), or severe (IVF <23 dB) 44.
Demographic characteristics including age, race, sex, living arrangement (living alone vs. living with another), education, and any fall occurrence last year were collected at baseline using a standard questionnaire. Polypharmacy was defined as using ≥ five non-eyedrop medications by direct observation of medication bottles or questionnaire. The number of comorbidities was the sum of comorbidities collected from a list of comorbid conditions described elsewhere.45 Cognitive function was obtained using the Mini-Mental State Exam for visually impaired (MMSE-VI) questionnaire.
Statistical analysis
Study participants were included in the analyses if they had both valid accelerometer and FoF data at baseline, and at one or more of the three follow-up visits. Differences in demographic and clinical characteristics of study participants by fall status were evaluated using t-test for continuous variables and χ2 test for categorical variables. Fitted plots of physical activity outcomes (including average steps, active minutes and MVPA minutes) and FoF scores over the three-year follow-up period were created to visualize the direction and magnitude of longitudinal changes in each fall group (Figure 1&2). Based on the appearance of the physical activity and FoF changes over time, linear mixed-effects models were used to study the longitudinal change in each outcome (average steps, active minutes, MVPA minutes and FoF) as a function of first-year falls categorization (non-faller, non-injurious faller, or injurious faller) by including fall category, follow-up time (in years), and an interaction of falls category and follow-up time in each model. Other model covariates included age, IVF, race, sex, living arrangement, education, polypharmacy, comorbidity, and cognitive function. For all models, unstructured correlation models were employed and standardized residuals were compared to predicted values to ensure goodness of fit. Statistical significance was defined using two-sided hypothesis testing with α of 0.05. All analyses were performed using Stata STATA 15.0 (StataCorp LP, College Station, Texas, USA).
Figure 1.
(A) Average daily steps by fall status at each assessment over the three-year follow-up period. (B) Active minutes by fall status at each assessment over the three-year follow-up period. Note: Error bars represent 95% confidence intervals.
Figure 2.
(A) Moderate & vigorous active minutes by fall status at each assessment over the three-year follow-up period. (B) Rasch-derived fear of fall scores by fall status at each assessment over the three-year follow-up period. Note: Error bars represent 95% confidence intervals.
Results
For the 234 study participants, mean age was 70.5 (Standard Deviation [SD]=7.6), 51.3% were men, 20.5% lived alone, 85.2% had some college degree or higher, and 42% reported a fall in the prior year. Mean IVF sensitivity was 27.1 dB (SD=4.5 dB), and roughly half of participants had normal/mild vision field damage, while 40.6% and 10.3% had moderate and severe visual field damage, respectively. The mean visual acuity-logMAR for better-seeing eye was 0.10 (SD=0.20), nearly one third (32%) used five or more non-eye prescription medications, and the average MMSE-VI value was 20.0 (SD=2.0). Over the first year, roughly half (54.7%) of participants were non-fallers, while 20.9% and 24.4% were classified as non-injurious fallers and injurious fallers, respectively (Table 1). Of these injurious fallers (N=57), 12% were admitted to hospital, 19% had a fracture, 13% had joint dislocation, 20% sprained a ligament, 25% pulled a muscle, 65% had swelling, 71% had bruising, and 94% had pain. Number of comorbidities varied across first-year fall status (ANOVA p<0.01), with a higher proportion of injurious fallers describing two or more comorbidities (82%) as compared to non-fallers (57%) and non-injurious fallers (64%).
Table 1.
Participant baseline demographic and clinical characteristics by non-faller, non-injurious faller and injurious faller
| Non-faller N = 128 |
Non-injurious faller N = 49 |
Injurious faller N = 57 |
P-value | |
|---|---|---|---|---|
| Demographic characteristics | ||||
| Age, mean (SD) | 69.6 (7.8) | 71.1 (7.8) | 71.7 (7.0) | 0.18 |
| Male, n (%) | 70 (55) | 24 (50) | 26 (46) | 0.49 |
| African American, n (%) | 40 (31) | 15 (31) | 13 (23) | 0.49 |
| Live alone, n (%) | 26 (20) | 10 (20) | 12 (21) | 0.99 |
| Education | 0.78 | |||
| ≤ High school, n (%) | 21 (16) | 8 (16) | 7 (12) | |
| Some college, n (%) | 18 (14) | 7 (14) | 6 (11) | |
| Bachelor, n(%) | 35 (27) | 12 (25) | 12 (21) | |
| ≥ Master, n (%) | 54 (42) | 22 (45) | 32 (56) | |
| Any falls occurrence last year | 51 (40) | 21 (42) | 27 (47) | 0.63 |
| Clinical characteristics | ||||
| IVF sensitivity, mean (SD) | 27.1 (4.9) | 26.7 (4.5) | 27.3 (3.4) | 0.75 |
| Normal/mild VF damage (%) | 64 (50) | 22 (45) | 29 (51) | |
| Moderate VF damage (%) | 50 (39) | 21 (43) | 24 (42) | |
| Severe VF damage (%) | 14 (11) | 6 (12) | 4 (42) | |
| Better-eye visual-acuity logMAR, mean (SD) |
0.11 (0.21) | 0.11 (0.23) | 0.06 (0.12) | 0.23 |
| Polypharmacy, n (%) | 37 (32) | 30 (32) | 9 (38) | 0.86 |
| No. of comorbidities | 0.01 | |||
| ≤ 1, n (%) | 55 (43) | 18 (37) | 10 (18) | |
| 2–3, n (%) | 49 (38) | 19 (39) | 35 (61) | |
| 4–5, n (%) | 24 (19) | 12 (25) | 12 (21) | |
| MMSE-VI, mean (SD) | 20 (2) | 20 (2) | 20 (2) | 0.82 |
Note. SD: standard deviation; IVF: integrated vision field (in decibels); VF: visual field; Normal/mild VF damage: IVF >28 dB; Moderate VF damage: IVF: 23–28 dB; Severe VF damage: IVF <23 dB; Polypharmacy: ≥ 5 systemic prescription medications; MMSE-VI: Mini-Mental State Examination-Vision Impairment (maximum as 22).
Baseline physical activity measurements were available in all 234 participants, while 210 (89.7%), 190 (81.2%), and 171 (73.1%) had physical activity data available at the end of the 1st, 2nd, and 3rd study years, respectively. Similarly, all participants completed FoF questionnaire in the first year, while 219 (93.6%), 199 (85.0%) and 182 (77.8%) completed the FoF after the 1st, 2nd, and 3rd study years, respectively.
When assessing activity changes over the three-year study period within groups defined by first-year fall status, average daily steps (−350 steps/day, 95% confidence interval [CI]: −653, −47) and active minutes (−11 minutes/day, 95% CI: −17, −4) declined per each year for injurious fallers (Table 2); however, both steps and active minutes remained unchanged for non-fallers and non-injurious fallers (p>0.27 for all) (Figure 1). No significant changes in time spent in MVPA were noted within for any group (p>0.18 for all) (Figure 2A). When comparing activity changes over the three-year study period across groups defined by first-year fall status, physical activity among injurious fallers showed greater annual (per year) declines in daily steps (−425 steps/day, 95% CI: −793, −57), daily active minutes (−13 minutes/day, 95% CI: −21, −6), and daily moderate and MVPA minutes (−3 MVPA minutes/day, 95% CI: −5, 0) over the three-year study period as compared to non-fallers (Table 2); non-injurious fallers, however, did not show significant differences in the three activity measures compared to non-fallers (including average steps, active minutes, MVPA minutes) (p>0.11 for all).
Table 2.
Longitudinal changes in physical activity and self-reported measures across fall status
| Outcomes | Non-faller (β, 95% CI) |
Non-injurious faller (β, 95% CI) |
Injurious faller (β, 95% CI) |
Difference between non-injurious vs non-faller (β, 95% CI) |
Difference between injurious vs non-faller (β, 95% CI) |
|---|---|---|---|---|---|
| Physical activity | |||||
| Average steps (steps/day) |
74.83 (−133.36, 283.02) |
−118.41 (−447.00, 210.19) |
−349.93 (−653.24, −46.62)* |
−193.24 (−582.14, 195.67) |
−424.76 (−792.63, −56.90)* |
| Active minutes (minutes/day) |
2.50 (−1.93, 6.93) |
−1.50 (−8.50, 5.50) |
−10.89 (−17.33, −4.45)* |
−4.00 (−12.29, 4.29) |
−13.39 (−21.21, −5.57)* |
| Moderate & vigorous active minutes (minutes/day) |
1.04 (−0.46, 2.854) |
−1.26 (−3.62, 1.11) |
−1.47 (−3.66, 0.71) |
−2.29 (−5.10, 0.51) |
−2.51 (−5.16, −0.14)* |
| Self-reported measures | |||||
| Fear of falling (units/day) |
0.04 (0, 0.08) | 0.06 (0, 0.13) | 0.08 (0.02, 0.13)* | 0.03 (−0.05, 0.10) | 0.04 (−0.03, 0.11) |
Note. Mixed effects estimates adjusted for age, integrated vision field (IVF) sensitivity, race, sex, living arrangement, education, comorbidity, polypharmacy, and cognitive function.
CI: confidence interval.
p<0.05 by comparing with non-faller groups
When assessing FoF changes over the three-year study period within groups defined by first-year fall status, Marginally significant increases in FoF over three-year study period were observed for injurious fallers (0.08 units, 95% CI: 0.02, 0.13), while no statistically significant increases were observed for non-fallers (0.04 units, 95% CI: 0, 0.08) or non-injurious fallers (0.06 units, 95% CI: 0, 0.13) (Figure 2B). When comparing FoF changes over the three-year study period across groups, greater FoF levels over time was not observed by comparing either injurious fallers (0.04 units, 95% CI: −0.03, 0.11) or non-injurious fallers (0.03 units, 95% CI: −0.05, 0.10) to non-fallers.
Model estimates for year-by-year values of physical activity and FoF measures across first year fall status were displayed in Table 3.
Table 3.
Model estimated physical activity and self-reported measures at each follow-up year across fall status
| Follow-up | Outcomes | Non-faller | Non-injurious faller | Injurious faller |
|---|---|---|---|---|
| Baseline | Average steps | 3809.74 | 4282.95 | 4581.31 |
| Active minutes | 139.43 | 149.12 | 171.45 | |
| Moderate & vigorous active minutes | 9.62 | 12.12 | 13.85 | |
| Fear of falling | −0.03 | 0.09 | 0.07 | |
| 1st year | Average steps | 3926.36 | 4206.33 | 4273.17 |
| Active minutes | 142.95 | 148.63 | 161.59 | |
| Moderate & vigorous active minutes | 10.88 | 11.09 | 12.61 | |
| Fear of falling | 0 | 0.15 | 0.14 | |
| 2nd year | Average steps | 4019.95 | 4106.69 | 3942 |
| Active minutes | 145.81 | 147.49 | 151.06 | |
| Moderate & vigorous active minutes | 12.08 | 10.00 | 11.30 | |
| Fear of falling | 0.04 | 0.21 | 0.21 | |
| 3rd year | Average steps | 4111.67 | 4005.17 | 3608.96 |
| Active minutes | 148.75 | 146.44 | 140.62 | |
| Moderate & vigorous active minutes | 13.19 | 8.82 | 9.90 | |
| Fear of falling | 0.08 | 0.28 | 0.29 | |
Note. Mixed effects estimates adjusted for age, integrated vision field (IVF) sensitivity, race, sex, living arrangement, education, comorbidity, polypharmacy, and cognitive function.
Discussion
In a longitudinal study of changes in physical activity and FoF levels in persons with varying degrees of visual impairment, we found a long-lasting impact of falls on mobility (specifically physical activity) after injurious falls, but not after non-injurious falls. Specifically, first-year injurious falls were associated with a significant decline in physical activity over the three-year study period, but with minimal changes in FoF. However, non-injurious falls were not associated with a drop in physical activity nor a worsening of FoF over the full study period, nor were such changes observed in non-fallers. Our findings indicate that among persons with varying degrees of visual impairment, including some with normal visual fields, injurious fallers lower their daily activity over time but do not demonstrate higher levels of FoF compared to their counterparts who do not fall.
Our results add to the published literature examining whether falls, or injuries occurring with falls, are associated with restriction of physical activity.4,15 A cross-sectional study from the Baltimore Longitudinal Study of Aging (BLSA) did not find associations between self-reported falls in the last year and accelerometer-defined physical activity.4 However, the impact of fall status on the within-individual change in activity over time was not evaluated. A three-year longitudinal study did find that injurious falls were associated with lower physical activity levels; however, physical activity was obtained by self-report, which typically shows very poor correlations with objective measures of physical activity,20–22 and is less reflective of important biological parameters such as BMI, diabetes and hypertension.46 As such, our longitudinal study, which captured falls prospectively through monthly mail in calendars, and examined physical activity objectively over four annual visits, provides greater accuracy and is less subject to bias than prior studies. Our data also allow for a more quantitative understanding of physical activity decline after falls. In the BLSA, investigators demonstrated an average drop of 1.3% per year in overall activity from mid-to-late life,22 similar to our non-faller and non-injurious faller groups, but less than the decline observed in our injurious fallers (roughly 7% fewer steps and 7% fewer active minutes per year).
Our study also examined whether fall status was associated with changes in FoF over time. Previous research has demonstrated that retrospective report of a fall within the last 3 or 12 months were associated with a higher likelihood of FoF, as judged by the individual’s response to the question “do you ever limit activities because you are afraid of falling?” or “have you been worried or afraid that you might fall?”47 The use of a single question to evaluate FoF will have less precision for measuring within-person changes in FoF as compared to the current approach which uses a reliable and valid questionnaire that enables quantifying FoF levels and changes in levels. Our study demonstrated that first-year injurious fallers had marginally significant worsening of FoF over the three year study period; however, worsening of FoF at a rate just short of statistical significance was also observed in the non-faller and non-injurious faller groups, and the rate of FoF changes over time were not significantly different between those with injurious falls, non-injurious falls, or no falls over the first study year. Thus, it is not clear that fall-related injuries, when evaluated over a single study year, have a clear influence on the longitudinal trajectory of FoF, though it remains possible that severe injuries and/or repeated falls may impact FoF over time. Our study supports the notion that factors other than falls contribute to FoF, as persons who did not experience falls also developed FoF. Other factors leading to FoF may include psychological factors (e.g., fall experience with friends or family), and instances of near-falls.
Our findings strongly suggest that older adults with varying degrees of vision impairment are more vulnerable to future adverse mobility outcomes after an injurious fall as compared to those experiencing a fall that is non-injurious. Injurious falls in this study, not non-injurious falls, were associated with reductions in physical activity over the three-year study period. An observational study of 8188 healthy women aged 70–75 in Australia reported that lower physical activity was associated with an increased risk of fall-related bone fracture;16 our findings emphasize these relationships could be reciprocal, with fall-related injuries may also resulting in less physical activity. Of note, the present study suggests that fall-related injuries may contribute to functional decline over a long period extending well past the fall occurrence (up to 3 years).
The magnitude of annual declines in activity (−425 steps/day and −13 active minutes/day) in injurious falls compared to non-fallers is significant given that previous studies report that 30 fewer daily minutes of walking is associated with a 23% higher risk of coronary heart disease,48 and fewer steps per day is significantly associated with higher all-cause mortality (hazard ratio=2.04 for 4000 steps/day vs. 8000 steps/day).49 We also observed an annual average of 3 fewer minutes of MVPA/day (roughly 20 fewer weekly minutes) for injurious fallers as compared to non-fallers, which is substantial given that World Health Organization (WHO) recommends older adults should conduct at least 150 minutes of moderate-intensity physical activity a week to maintain functional capability and overall well-being. Our data add compelling evidence about the impact of substantial mobility declines associated with injurious falls on longevity and well-being, which supports the need for interventions to prevent injurious falls and rehabilitation programs to enhance the recovery from any detrimental effects of falls, particularly with regards to safely resuming/increasing physical activity.
Our study has several limitations. First, study participants were recruited from one study site and had varying degrees of visual impairment, including some with normal visual fields; therefore our results may not be generalizable to all visually impaired older people, or patients without visual impairments. As such, it remains unclear whether any fall occurrences with respect to other illnesses (other than visual damage) also influence the longitudinal change of physical activity and FoF in the same manner. Additionally, other factors (e.g., home hazard modification)50 might confound the association between falls status and activity in observational studies, though such factors would only affect results if they were differential across fall status. Moreover, such changes, if protective, would tend to bias our results towards the null. Additionally, we did not conduct subgroup analysis by types of injurious falls in more details that could impact function and FoF, as there were too few participants in each injury type subgroup to make statistical comparisons meaningful. Further, it was our original hypothesis (set forth in our grant) that first-year fall events would have implications for physical activity and fear of falling over the full 3 year study period (declines were still expressed as change per year, given that complete follow-up was not present in all participants). However, it is quite possible, perhaps even likely, that the impact of injurious falls varied over time. Indeed, it might appear from Figure 1A that injurious falls were associated with physical activity decline in the year of the fall, with these declines sustained in later years, while non-injurious falls created a decline that was temporary. We did not formally test the significance of these trends noted post-hoc, though they should be evaluated in future studies. Finally, participants were categorized by types of falls based on falls data collected from initial first year, and it is possible that in real lives people could make transitions from one group to another, e.g., people who were initial non-fallers might become fallers in follow-up years and those who were fallers might not fall again. However, the overall fall frequency remained similar in the 3-year period and the risk of falling in follow-up years was higher for fallers vs. non-fallers in the first year, hence, we did not include fall frequency for the follow-up years in present study.
In summary, our study found that in older adults with varying degrees of visual impairment, injurious falls contributed to a substantial change in physical activity over the three-year study period, although FoF levels remained almost unchanged. However, non-injurious falls were associated with neither a drop in physical activity over the full study period nor worsening of FoF. Further work is needed to identify effective interventions to prevent injurious falls and evaluate rehabilitation programs to improve physical and mental recovery from falls, particularly those resulting in injury.
Key points:
Injurious falls were associated with a significant decline in physical activity over the three-year study period, but not with changes in fear of falling.
Non-injurious falls were not associated with a drop in physical activity nor worsening in fear of falling.
Therapies to prevent falls and improve physical and mental recovery from falls, particularly those resulting in injury, are important for older adults with visual impairment.
Why does this paper matter?
This paper characterizes how longitudinal changes in objectively measured physical activity and fear of falling are related to injurious and non-injurious falls in visually impaired older adults.
Acknowledgement
The research was supported in part by National Institutes of Health Grant EY022976.
Sponsor’s Role:
The founding organization play no role in the design and conduct of this research.
Footnotes
Conflict of Interest
Authors have no conflict of interest to declare.
Reference.
- 1.Stevens JA, Mack KA, Paulozzi LJ, Ballesteros MF. Self-reported falls and fall-related injuries among persons aged>or=65 years - United States, 2006. J Safety Res. 2008;39:345–349. [DOI] [PubMed] [Google Scholar]
- 2.Hausdorff JM, Rios DA, Edelberg HK. Gait variability and fall risk in community-living older adults: a 1-year prospective study. Arch Phys Med Rehabil. 2001;82:1050–1056. [DOI] [PubMed] [Google Scholar]
- 3.Black AA, Wood JM, Lovie-Kitchin JE. Inferior field loss increases rate of falls in older adults with glaucoma. Optom Vis Sci. 2011;88:1275–1282. [DOI] [PubMed] [Google Scholar]
- 4.Nastasi AJ, Ahuja A, Zipunnikov V, Simonsick EM, Ferrucci L, Schrack JA. Objectively measured physical activity and falls in well-functioning older adults: findings from the Baltimore Longitudinal Study of Aging. Am J Phys Med Rehabil. 2018;97:255–260. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Kallinen M, Markku A. Aging, physical activity and sports injuries. An overview of common sports injuries in the elderly. Sports Med. 1995;20:41–52. [DOI] [PubMed] [Google Scholar]
- 6.Evans JR, Fletcher AE, Wormald RP, et al. Prevalence of visual impairment in people aged 75 years and older in Britain: results from the MRC trial of assessment and management of older people in the community. Br J Ophthalmol. 2002;86:795–800. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Haymes SA, Leblanc RP, Nicolela MT, Chiasson LA, Chauhan BC. Risk of falls and motor vehicle collisions in glaucoma. Invest Ophthalmol Vis Sci. 2007;48:1149–1155. [DOI] [PubMed] [Google Scholar]
- 8.Kumar A, Carpenter H, Morris R, Iliffe S, Kendrick D. Which factors are associated with fear of falling in community-dwelling older people? Age Ageing. 2014;43:76–84. [DOI] [PubMed] [Google Scholar]
- 9.Parry SW, Deary V, Finch T, et al. The STRIDE (Strategies to Increase confidence, InDependence and Energy) study: cognitive behavioural therapy-based intervention to reduce fear of falling in older fallers living in the community - study protocol for a randomised controlled trial. Trials. 2014;15:210. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Piercy KL, Troiano RP, Ballard RM, et al. The physical activity guidelines for Americans. JAMA. 2018;320:2020–2028. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.E JY, Schrack JA, Mihailovic A, et al. Patterns of daily physical activity across the spectrum of visual field damage in glaucoma patients. Ophthalmology. 2020;127 (Epub). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.West CG, Gildengorin G, Haegerstrom-Portnoy G, Schneck ME, Lott L, Brabyn JA. Is vision function related to physical functional ability in older adults? J Am Geriatr Soc. 2002;50:136–145. [DOI] [PubMed] [Google Scholar]
- 13.Chen SP, Bhattacharya J, Pershing S. Association of vision loss with cognition in older adults. JAMA Ophthalmol. 2017;135:963–970. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Sengupta S, van Landingham SW, Solomon SD, Do DV, Friedman DS, Ramulu PY. Driving habits in older patients with central vision loss. Ophthalmology. 2014;121:727–732. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Tinetti ME, Williams CS. The effect of falls and fall injuries on functioning in community-dwelling older persons. J Gerontol A Biol Sci Med Sci. 1998;53:M112–119. [DOI] [PubMed] [Google Scholar]
- 16.Heesch KC, Byles JE, Brown WJ. Prospective association between physical activity and falls in community-dwelling older women. J Epidemiol Community Health. 2008;62:421–426. [DOI] [PubMed] [Google Scholar]
- 17.Caban-Martinez AJ, Courtney TK, Chang WR, et al. Leisure-time physical activity, falls, and fall injuries in middle-aged adults. Am J Prev Med. 2015;49:888–901. [DOI] [PubMed] [Google Scholar]
- 18.Chan BK, Marshall LM, Winters KM, Faulkner KA, Schwartz AV, Orwoll ES. Incident fall risk and physical activity and physical performance among older men: the Osteoporotic Fractures in Men Study. Am J Epidemiol. 2007;165:696–703. [DOI] [PubMed] [Google Scholar]
- 19.Ballemans J, Zijlstra GA, van Rens GH, Schouten JS, Kempen GI. Usefulness and acceptability of a standardised orientation and mobility training for partially-sighted older adults using an identification cane. BMC Health Serv Res. 2012;12:141. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Washburn RA. Assessment of physical activity in older adults. Res Q Exerc Sport. 2000;71:79–87. [DOI] [PubMed] [Google Scholar]
- 21.Prince SA, Adamo KB, Hamel ME, Hardt J, Connor Gorber S, Tremblay M. A comparison of direct versus self-report measures for assessing physical activity in adults: a systematic review. Int J Behav Nutr Phys Act. 2008;5:56. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Schrack JA, Cooper R, Koster A, et al. Assessing the “physical cliff”: detailed quantification of age-related differences in daily patterns of physical activity. J Gerontol A Biol Sci Med Sci. 2016;71:1039–1048. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Troiano RP, Berrigan D, Dodd KW, Masse LC, Tilert T, McDowell M. Physical activity in the United States measured by accelerometer. Med Sci Sports Exerc. 2008;40:181–188. [DOI] [PubMed] [Google Scholar]
- 24.van Poppel MN, Chinapaw MJ, Mokkink LB, van Mechelen W, Terwee CB. Physical activity questionnaires for adults: a systematic review of measurement properties. Sports Med. 2010;40:565–600. [DOI] [PubMed] [Google Scholar]
- 25.Garcia PA, Dias JMD, Silva SLA, Dias RC. Prospective monitoring and self-report of previous falls among older women at high risk of falls and fractures: a study of comparison and agreement. Brazilian journal of physical therapy. 2015;19:218–226. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26.van Landingham SW, Massof RW, Chan E, Friedman DS, Ramulu PY. Fear of falling in age-related macular degeneration. BMC Ophthalmol. 2014;14:10. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27.Arfken CL, Lach HW, Birge SJ, Miller JP. The prevalence and correlates of fear of falling in elderly persons living in the community. Am J Public Health. 1994;84:565–570. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 28.Howland J, Lachman ME, Peterson EW, Cote J, Kasten L, Jette A. Covariates of fear of falling and associated activity curtailment. Gerontologist. 1998;38:549–555. [DOI] [PubMed] [Google Scholar]
- 29.Scheffer AC, Schuurmans MJ, van Dijk N, van der Hooft T, de Rooij SE. Fear of falling: measurement strategy, prevalence, risk factors and consequences among older persons. Age Ageing. 2008;37:19–24. [DOI] [PubMed] [Google Scholar]
- 30.Ramulu PY, van Landingham SW, Massof RW, Chan ES, Ferrucci L, Friedman DS. Fear of falling and visual field loss from glaucoma. Ophthalmology. 2012;119:1352–1358. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 31.E JY, Mihailovic A, Kuo PL, et al. Characterizing the impact of fear of falling on activity and falls in older adults with glaucoma. J Am Geriatr Soc. 2020;68:1847–1851. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 32.Jorstad EC, Hauer K, Becker C, Lamb SE. Measuring the psychological outcomes of falling: a systematic review. J Am Geriatr Soc. 2005;53:501–510. [DOI] [PubMed] [Google Scholar]
- 33.Dias RC, Freire MT, Santos EG, Vieira RA, Dias JM, Perracini MR. Characteristics associated with activity restriction induced by fear of falling in community-dwelling elderly. Rev Bras Fisioter. 2011;15:406–413. [PubMed] [Google Scholar]
- 34.Yardley L, Smith H. A prospective study of the relationship between feared consequences of falling and avoidance of activity in community-living older people. Gerontologist. 2002;42:17–23. [DOI] [PubMed] [Google Scholar]
- 35.Lachman ME, Howland J, Tennstedt S, Jette A, Assmann S, Peterson EW. Fear of falling and activity restriction: the survey of activities and fear of falling in the elderly (SAFE). J Gerontol B Psychol Sci Soc Sci. 1998;53:43–50. [DOI] [PubMed] [Google Scholar]
- 36.Mihailovic A, Swenor BK, Friedman DS, West SK, Gitlin LN, Ramulu PY. Gait implications of visual field damage from glaucoma. Transl Vis Sci Technol. 2017;6:23. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 37.Davalos-Bichara M, Lin FR, Carey JP, et al. Development and validation of a falls-grading scale. J Geriatr Phys Ther. 2013;36:63–67. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 38.Ramulu PY, Mihailovic A, West SK, Friedman DS, Gitlin LN. What is a falls risk factor? factors associated with falls per time or per step in individuals with glaucoma. J Am Geriatr Soc. 2019;67:87–92. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 39.Togo F, Watanabe E, Park H, et al. How many days of pedometer use predict the annual activity of the elderly reliably? Med Sci Sports Exerc. 2008;40:1058–1064. [DOI] [PubMed] [Google Scholar]
- 40.Colley RC, Tremblay MS. Moderate and vigorous physical activity intensity cut-points for the Actical accelerometer. J Sports Sci. 2011;29:783–789. [DOI] [PubMed] [Google Scholar]
- 41.Velozo CA, Peterson EW. Developing meaningful fear of falling measures for community dwelling elderly. Am J Phys Med Rehabil. 2001;80:662–673. [DOI] [PubMed] [Google Scholar]
- 42.Boone WJ. Rasch analysis for instrument development: why, when, and how? CBE Life Sci Educ. 2016.15:rm4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 43.Muthén LK, Muthén BO. Mplus User’s Guide, 7th edition. Los Angeles, CA: Muthén & Muthén; 1998. [Google Scholar]
- 44.Hodapp E, Parrish PK, Anderson DR. Clinical decisions in glaucoma. St. Louis, MO: Mosby Co; 1993. [Google Scholar]
- 45.Turano KA, Broman AT, Bandeen-Roche K, Munoz B, Rubin GS, West S. Association of visual field loss and mobility performance in older adults: Salisbury Eye Evaluation Study. Optom Vis Sci. 2004;81:298–307. [DOI] [PubMed] [Google Scholar]
- 46.Atienza AA, Moser RP, Perna F, et al. Self-reported and objectively measured activity related to biomarkers using NHANES. Med Sci Sports Exerc. 2011;43:815–821. [DOI] [PubMed] [Google Scholar]
- 47.Friedman SM, Munoz B, West SK, Rubin GS, Fried LP. Falls and fear of falling: which comes first? A longitudinal prediction model suggests strategies for primary and secondary prevention. J Am Geriatr Soc. 2002;50:1329–1335. [DOI] [PubMed] [Google Scholar]
- 48.Zheng H, Orsini N, Amin J, Wolk A, Nguyen VT, Ehrlich F. Quantifying the dose-response of walking in reducing coronary heart disease risk: meta-analysis. Eur J Epidemiol. 2009;24:181–192. [DOI] [PubMed] [Google Scholar]
- 49.Saint-Maurice PF, Troiano RP, Bassett DR Jr., et al. Association of daily step count and step intensity with mortality among US adults. JAMA. 2020;323:1151–1160. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 50.E JY, Li T, McInally L, et al. Environmental and behavioural interventions for reducing physical activity limitation and preventing falls in older people with visual impairment. Cochrane Database Syst Rev. 2020;9:Cd009233. [DOI] [PMC free article] [PubMed] [Google Scholar]