STRENGTHS AND LIMITATIONS OF THIS STUDY

This was the first study that evaluated the association between fear of falling and performance-based physical function and low back pain among Iranian older adults.

The study examined different aspects of performance-based physical function, using objective physical performance tests.

Mild pain in other participants’ joints (eg, knees or hips) may have affected the study’s results.

Participants in the study were mostly classified as young-old, which may limit the generalisability of the results.

The study’s cross-sectional design limits its evidence level.

Introduction

Among older adults, falls and fear of falls seriously threaten their safety and independence. The experience of a fall can lead some older adults to disengage from physical activity due to fear of falling, which is recognised as a psychological factor that contributes to avoiding physical activity and influencing clinical outcomes in older adults.1–3 Studies have shown that older individuals who fear falling have poorer balance, lower muscle strength and lower physical activity levels.3 4

Regular physical function is essential for healthy ageing and long-life.5 Moreover, it contributes to the prevention of several chronic diseases (such as cardiovascular disease, hypertension and obesity) as well as improving social interactions, mobility and cognitive performance. Physical function deficits are associated with an increased risk of falls, limitations in living independently and poorer self-perception of health.6 Despite the positive effects of physical function, most older adults do not meet recommended physical function levels.7 8 Physical performance tests have increasingly been used in research and geriatric assessment.9 Compared with self-reported physical performance measures, objective physical performance tests use standardised methodology and provide a more comprehensive measure of a person’s function.10 Physical performance tests such as the Timed Up and Go (TUG), the 30 s Sit-To-Stand (30s-STS), the single leg stance with open and closed eyes (Open/Close Eyes SLS) and the gait speed test are used in clinical practice to assess different aspects of older adults functioning.11–14

Low back pain (LBP) is the most common health issue among older adults resulting in disability.15 16 The prevalence of LBP among older adults ranges from 21% to 75%, suggesting this is a highly prevalent health issue.17 There has been consistent evidence that LBP adversely affects both physical and psychological well-being.18–20 Approximately 30% of older adults who suffer from degenerative spinal changes associated with LBP are at risk of losing function and independence, which represents a major threat to healthy ageing.21 22

Extensive studies on the fear of falling have been done in previous research, particularly on its association with sociodemographics and health-related factors.23–25 Also, previous studies have shown older adults with a fear of falling had poorer physical activity levels,26 27 balance and lower muscle strength4 than those without. Moreover, in the study of well-functioning elderly individuals, those who reported some fear of falling, but had no criteria of frailty, had similar gait performance as those with one or more frailty criteria and no fear of falling.28

Overall, previous studies demonstrate that fear of falling is common among older adults and is associated with numerous negative outcomes. Although the association of fear of falling with many risk factors has been widely explored, few have explored other influencing factors such as LBP and physical function status. It is unclear which factors (LBP and physical function) could be a stronger indicator of fear of falling in older adults. Understanding the association of fear of falling with performance-based physical function and LBP can be helpful to develop interventions that aim to modify these determinants in older adults. This study evaluated the association between fear of falling and performance-based physical function and LBP among older adults. The study hypotheses were (a) a high fear of falling is associated with lower levels of physical function and (b) a fear of falling is positively associated with having LBP.

MethodsStudy design

This cross-sectional study is reported according to Strengthening the Reporting of Cross-sectional Observational Studies and was conducted in the physiotherapy department of the Iran University of Medical Sciences laboratory between March 2022 and April 2023.

Participants

140 subjects over 60 years, with and without LBP were recruited. The study recruited older adults with LBP from Iran University orthopaedic and/or physiotherapy outpatient clinics. Older adults with a history of LBP lasting more than 3 months in the past year, recurrent LBP for at least two episodes of pain, lasting two consecutive days in the last year29 and with a pain score between 30 and 70 mm on a Visual Analogue Scale (VAS)30 were included.

Older adults without LBP were recruited through advertisements at the university and in the local community. The inclusion criteria for the non-LBP subjects were no LBP in the previous year or back pain lasting more than 1 week in the last year.31 One physiotherapist checked the eligibility criteria of the participants and conducted the assessments.

Exclusion criteria for LBP and non-LBP subjects were pelvic or spinal surgery, congenital spinal malformation or scoliosis, degenerative neurologic disease, severe labyrinthitis; history of dizziness and use of medicine affecting balance, history of foot, knee and hip surgery, chronic cardiovascular or respiratory diseases, rheumatoid arthritis, falls in the past year, Mini-Mental State Examination score <21 and Oswestry Disability Index scores >25, pain score ≥30 mm according to VAS in any part of the body other than the lower back (neck, hips, knees, etc) and ambulatory limitation caused by persistent lower-extremity pain.

MeasuresDependent variableFear of falling

Fear of falling was assessed using the Falls Efficacy Scale International (FES-I). This questionnaire has 16 items that assess a person’s concern about falling during daily activities. Each item is scored on a scale of 1–4 with a total score ranging from 16 to 64. Higher scores indicate a greater fear of falling.32 FES-I has shown acceptable measurement properties for assessing the fear of falling in Iranian older adults.33 The cut-point to differentiate between the low and high concern about falling was considered 16–22 and 23–64 out of 64, respectively.34

Independent variableLow back pain

In the baseline survey, participants were asked if they had experienced chronic LBP lasting more than 3 months in the past year or recurrent LBP for at least two episodes of pain, lasting two consecutive days in the past year. Eligible subjects were classified into two groups based on having or not having LBP.

Performance-based physical function measuresTimed Up and Go

TUG test was used to assess functional mobility.35 Participants were asked to stand up from a chair, walk 3 m at their comfortable speed, turn, walk back towards the chair and sit down. The duration of the test was measured in seconds using a stopwatch.11 This test is recommended as a screening tool for fall risk36 and a valid tool to predict impaired activity and daily living functions in older people.37

30s-Sit-To-Stand

The 30s-STS test was used to evaluate lower extremity muscle function. Participants were instructed to sit on a chair with their feet on the ground and arms crossed in front of their chest, then perform STS transitions as quickly and safely as comfortably over 30 s. The number of complete repetitions was measured as the outcome, and a higher number indicates better lower extremity function.13 The 30s-STS is a reliable and valid tool for use in the general geriatric population.38

Open/close eyes SLS

The Open/Close Eyes SLS test has been widely adopted, for assessing static balance and fall risk in older adults.39 40 The participants were timed while standing barefoot on their dominant leg, and lifting the foot of their remaining leg approximately 2 inches off the ground and 2 inches from the medial malleolus of the stance leg.39 The test was terminated on the participant stepping down, touching the standing leg with their other leg, touching the adjacent wall or opening the eyes in the eye-closed trials. The test had a time limit of 45 s. Participants took the test three times with their eyes open and three times with their eyes closed. The order of each trial was first done with eyes open, then closed. The average of tests was computed.41 The SLS indicates good reliability and validity in older adults.12 39

Gait speed test

The gait speed test was used to assess functional mobility and was measured by walking an 8 m distance. Participants were instructed to walk three times at a regular speed, and the meantime was recorded. The stopwatch was used to record walking time. The test has shown reliability and validity properties in older adults.14

Procedures

Demographic data were recorded at baseline. The Persian version of the FES-I was completed by all participants to assess fear of falling during daily activities. Participants perform TUG, 30s-STS, open/close eyes SLS and gait speed tests in random order during the same session to assess performance-based physical function. To minimise fatigue, 5 min of rest was taken between each test. One experienced physiotherapist conducted all the tests.

Patient and public involvement

There was no patient or public involvement in the design, conduct or dissemination plans of this study.

Statistical analysis

The sample size was calculated with G*Power, V.3.1.9.2 (Heinrich-Heine-Universität, Düsseldorf, Germany) for a linear multiple regression model. From a priori analysis, with an effect size of f2=0.15, the total number of predictors and covariates was 9, α=0.05 and the desired power of 85%, considering a 10% attrition rate the required sample size was 140.

Data analysis was conducted by using SPSS software, V.26. The normality of the data was assessed using a combination of the Shapiro‐Wilks test, histograms and skew/kurtosis. Spearman’s correlation was used for investigating the bivariate correlation between physical performance and LBP with a fear of falling. Correlation coefficient values were considered very weak (0–0.19), weak (0.20–0.39), moderate (0.40–0.69), strong (0.70–0.89) and very strong (0.90–1).42

The relationship between independent variables (physical function, LBP) and the dependent variable (fear of falling) was examined using multiple linear regression analysis. To control for demographic variables (age, gender, body mass index (BMI)) that may affect fear of falling, these variables were chosen prior to the study as potential covariates. In the model, only variables with significant bivariate correlation were included.

The following assumptions were tested to perform linear regression analysis: linearity (scatterplots), normality of residuals and homoscedasticity, which was tested by plotting the standardised residuals versus the fitted values. The variance inflation factor>3 was used to determine the presence of multicollinearity. Using a standardised β coefficient, the direction and strength of the association between each independent and dependent variable were depicted.

Stepwise regression analysis was conducted with the fear of falling as the dependent variable and only the significant independent variables from the preliminary multivariable analysis. The statistical significance level was set at p<0.05.

Results

Out of 293 potential subjects, 140 older adults were included in the study (figure 1). All variables except age followed an approximately normal distribution. Study participants mainly comprised young older adults (83.5%) with a mean age of 67.29 years. Detailed characteristics of the sample is shown in table 1.

Figure 1

Strengthening the Reporting of cross-sectional Observational studies (STROBE) flow diagram.

Table 1

Demographic and clinical characteristics of participants and separate data for participants with and without LBP

Bivariate association

Bivariate analysis revealed a significant correlation between fear of falling and physical function tests (TUG, gait speed, Open/Close Eyes SLS and 30s-STS), LBP and gender (p<0.05). According to Spearman’s r coefficient, there was a positive and moderate correlation between fear of falling and TUG, gait speed and female gender, positive and weak correlation with age, and also a negative and moderate correlation with Open/Close Eyes SLS, 30s-STS and not having LBP (table 2).

Table 2

Bivariate correlation analysis (n=140)

Linear regression analysis

All tested assumptions met the criteria for performing a linear regression analysis. The results indicated that 33.7% of the variance of the fear of falling was predicted by age, gender, BMI, having or not having back pain and physical function (F=8.84; p<0.001). Table 3 shows a significant direct association between gender as a covariate and fear of falling, with women reporting higher fears. Also, there was a significant indirect association between the 30s-STS test results and fear of falling; participants with a higher fear of falling performed fewer test repetitions. A stepwise regression was conducted only with significant independent variables from the multivariable regression analysis. The results of stepwise regression analysis revealed that the 30s-STS test (model 1) accounted for 17.8% of the variance score of the fear of falling. Adding gender to the model (model 2), increased the explained variance score to 31.5% (table 4).

Table 3

Multivariable linear regression analysis, representing the association between dependent variables (physical function, LBP and demographics as covariate) with the independent variable (fear of falling) (n=140)

Table 4

Stepwise linear regression analysis

Discussion

This study aimed to determine the association between fear of falling and performance-based physical function and LBP among older adults. The results revealed a significant association between fear of falling and the 30s-STS test score and the sex in older adults. In contrast, LBP and other performance-based physical function tests were not related to fear of falling. Female gender was the strongest indicator of fear of falling.

The findings support using 30s-STS as an alternative to the TUG, Open/Close Eyes SLS and gait speed tests when evaluating physical function and screening for fear of falling among older adults. Although this is the first known study that examined the relationship between fear of falling and 30s-STS in older adults with and without LBP, previous articles have examined the relationship between falling or fear of falling and other forms of STS test (eg, modified 30s-STS, five times STS) among healthy older adults. The modified 30s-STS predicted falls and the number of falls in older adults in long-term care.43 Also, older adults unable to complete the five times STS test had a marginally greater risk of falling than those who completed the test in a shorter time.44

Despite the significant relationship between fear of falling and the 30s-STS test scores, the relationship between fear of falling and the TUG, Open/Close Eyes SLS and the gait speed test was not significant. Some studies have examined the relationship between physical function and fall prediction. A systematic review examining older adults revealed that SLS was not a predictor of falls.12 Similarly, a systematic review and meta-analysis found no association between TUG and older adults falling.45 Also, a cohort study found no associations between gait speed and fear of falling among community‐dwelling older adults.46 Considering the current results and previous studies, fear of falling has the strongest relationship with the 30s-STS test. The 30s-STS test indicates lower extremity strength and lower extremity weakness is a risk factor for falls47 so the 30s-STS test should be considered when assessing older adults for fear of falling.

According to the results of the present study, having or not having LBP was not an indicator of fear of falling. Including older adults with moderate pain and low levels of disability may have resulted in this insignificant finding. Fear of falling may be more pronounced in older adults with LBP, suffering from greater pain and disability. Older adults with severe pain and higher disability levels might experience greater functional limitations and psychological distress, which could increase their fear of falling.48 49 Thus, extrapolation of the results to older adults with severe LBP and moderate to high disability should be undertaken with caution. Different results may emerge with those having severe pain intensity or moderate to high disability levels.

The findings of the present study showed that the female gender as a covariate, had the strongest association with a fear of falling. Previous studies have also found a sex influence on fear of falling. Consistent with the present study’s findings, the female sex was correlated independently with severe fear of falling50 and was a significant predictor of fear of falling in community‐dwelling older adults.51 52 It may be due to the fact that older females have a weaker musculoskeletal system and are more likely to develop osteoporosis. Consequently, their muscle strength and postural control deteriorate which can cause more fear of falling.53

Limitations

This study has some limitations. First, although FES-I is a valid and reliable questionnaire, recall bias may have occurred due to its self-reported nature. Second, study results may have been affected by mild pain in other joints of the participants (eg, knees or hips). Third, most of the participants were classified as young-old, which may limit the results’ generalisability. Fourth, the study included older adults with no or low disability to minimise safety concerns during performance-based physical function tests. Therefore, results cannot be generalised to those with moderate or severe disability. Finally, the study’s cross-sectional design limits its evidence level.

Conclusion

The presence of an association between fear of falling and lower extremity muscle function (measured by 30s-STS test) was supported in older adults. Also, fear of falling was associated with the female gender as a covariate. However, the association between fear of falling and LBP and some aspects of physical function could not be confirmed.

The results suggest that interventions designed to improve lower extremity muscle function should be recommended for older adults with a fear of falling. Furthermore, the observed association between the fear of falling and the female sex confirms the need for effective interventions in reducing the fear of falling among older women.

Data availability statement

Data are available on reasonable request. The data presented in this study are available on reasonable request from the corresponding author.

Ethics statementsPatient consent for publication

Consent obtained directly from patient(s).

Ethics approval

The study was conducted in accordance with the Declaration of Helsinki and approved by the Human Research Ethics Committee of the Iran University of Medical Sciences (IR.IUMS.REC.1400.272). Written informed consent has been obtained from all subjects involved in the study.