A comparison of objective physical activity, muscle strength, and depression among community-dwelling older women living in sloped versus non-sloped environments

Abstract

Objective

To examine the relationship between the living location and outcomes of physical activity level and physical and psychological functioning in older women. The specific aim was to understand the association between living in a sloped versus non-sloped environment and these outcomes.

Design

Cross-sectional study.

Setting and Participants

108 older women aged 65 years or older who resided in Nagasaki prefecture participated.

Measurements

Physical activity, lung function, muscle strength (hand grip and quadriceps force) and depressive symptoms were assessed objectively.

Results

In logistic regression, activity counts per day (OR 0.779, 95%CI 0.715-0.841, p<0.01), activity times per day (OR 0.821, 95%CI 0.801-0.913, p<0.01), hand grip force (OR 0.666, 95%CI 0.558-0.796, p<0.001), and depressed (Center for Epidemiological Studies Depression Scale score ≥16) (OR 1.093, 95%CI 1.019-1.427, p<0.05) showed statistically significant inverse associations with living in a sloped ground.

Conclusions

Since dwelling on sloped ground was associated with negative (lower physical activity levels, lower grip strength, and more depression) outcomes, a comprehensive geriatric assessment, related to all aspects of older women, is recommended. Planning of home exercise programs for the elderly should take such environmental factors into consideration.

Introduction

Worldwide, over 30% of adults are physically inactivity (1). The disadvantages of such inactivity have been well documented. Disease outcomes that are inversely related to regular physical activity in prospective observational studies include cardiovascular disease, stroke, cerebral vascular disease, diabetes, osteoporosis, obesity, anxiety and depression (2). Moreover, 9% of premature mortality has been attributed to physical inactivity (3). As these reports have noted, physical activity is a particularly important determinant of health and functioning in later life (4). Increases in the proportion of elderly people, along with increases in life expectancy, require that attention be given to them.

The importance of physical activity for healthy aging is supported in a documented. Individuals who engage in physical activity such as walking for 30 minutes a day reduce their risk of stroke by 24% (5). The home exercise including the walking is a good health benefits of physical activity have been confirmed scientifically in older adults (6, 7), and many community-based interventions related to physical activity have produced improvements in physical functioning (8, 9, 10). These general factors are all relevant to the design of physical activity programs for the elderly that they can reasonably implement in everyday life. Therefore it is important that we investigate the environment that it is easy for an elderly people to perform reasonably implement (i.e. walking). The relation between the built environment and the physical activity among seniors has been the subject of a limited number of studies (11). Despite decades of research, our understanding of the environmental factors that help promote regular physical activity is still in its infancy. In previous studies, a few studies focused on accessibility to facilities. In a few studies (12, 13, 14), convenience of facilities was not significantly associated with physical activity; other studies did find a significant relationship (15, 16, 17). Convenience of facilities appeared to have the most inconsistent findings among the research. Previous studies identified different results within specific aspects of the built environment. Furthermore there were studies that focused on the independent variables included the element of the slope. They reported mixed results for safety; traffic, streetlights, and high crime were not significant, but hills were associated with physical activity (16, 18). On the other hand, a study did not find a significant relationship (14). In addition, the psychosocial and appraisal barriers that directly and indirectly affect participation in physical activity include depression, general health and self-rated health (19, 20, 21, 22). From above studies, they used self-reported data or questionnaire. There has been no formal exploration of the influence that the environmental status of location has on physical functioning and psychosocial of elderly women. Furthermore almost all studies used self-reported data.

The aim of this study was to objectively examine associations between a particular aspect of residential location (the existence of slope or stairs) and physical functioning, including physical activity levels and depressive symptoms, in elderly women.

Methods

Participants and study design

We performed a prospective, cross-sectional survey on a stratified sample of community-dwelling older women, resident in Nagasaki city, Japan. Participants were eligible for inclusion if they were aged 65 or over and were ambulant without walk assisting tool and they do not have any diseases that may disrupt walking in daily life. In addition, the exclusion criteria were: exacerbation of symptoms within the previous 4 weeks, inability to perform exercise testing, neuromuscular disease, and cognitive impairment rendering them unable to complete the questionnaires. Potential participants were excluded if they were resident in institutional care (hospital, nursing or care home), were unable to give written informed consent and were unwilling to participate. All participants have married and they don't need their support i.e. financial, physical and emotional.

We recruited 108 healthy elderly women gathered at 7 community centers in Nagasaki city. The environmental status of locations was classified as follows: The definition of sloped ground is more than 20m above sea level or more than an angle of inclination 5 degrees by the regulations rule of Nagasaki city (23). In addition, the Slope group comprised those who lived in a place that had 20 or more stairs and a slope of 100 m or more between the driveway and the house; those whose residence did not meet these criteria were designated as the Non-Slope group. This criterion is based on a regulation of the city of Nagasaki by Public Nursing Care Insurance (23). In this research, we made assessment using a map based on an address.

Subjects completed a detailed questionnaire on demographic characteristics such as age, height, weight, education level (e.g., junior high school or high school or college or diploma at university, or university masters or doctorate or professional degree), family members and comorbidity.

We obtained written informed consent from participants and the study was approved by the Human Ethics Review Committee of Nagasaki University Graduate School of Biomedical Science (approval number: 08072424-2). Participants were not compensated for participation. The study conformed to the principles of the Declaration of Helsinki.

Physical activity

Physical activity was measured by a Uni-axial accelerometer (Lifecorder GS; Suzuken Corporation; Nagoya, Japan) for two weeks. This accelerometer records vertical acceleration as counts and activity times per day. Data were stored on a computer, and the mean daily step counts and activity times were calculated. Subjects were instructed to wear the accelerometer on a belt around their waist and to remove the monitor only for sleep and showering. First and last days' usage were excluded from analysis because these days contained incomplete data. The counts and activity times per day were recorded for 12 complete days. Minimum were time 16 hours. When body movement data were not recorded for more than 2 consecutive hours, the data for that day were excluded (24). Participants underwent measurements during spring.

Lung function

Lung function was measured using an electronic spirometer (FUDAC 70; Fukuda Sangyo Inc; Chiba, Japan). Forced expiratory volume in one second (FEV₁), forced vital capacity (FVC) and vital capacity (VC) were assessed in accordance with a standard protocol (25) and were repeated until at least three reproducible forced expiratory curves had been obtained.

Muscle strength

Quadriceps muscle force and handgrip force: Quadriceps force (QF) was measured as peak force developed during a maximal isometric knee extension maneuver with hip and knee in 90° flexion with sitting position on the dominant side using a hand-held dynamometer that was attached to a fixing-belt (μTas F-1; Anima Corporation; Tokyo, Japan) in accordance with a standard protocol that has demonstrated good test-retest reliability (interclass correlation coefficient 0.94) (26). The highest value from three attempts on the dominant side was recorded. Handgrip force (HF) was measured two attempts in the dominant hand while standing using a hand dynamometer (GRIP-D; OG Giken Corp., Okayama, Japan). The highest value from the two attempts was recorded.

Depressive symptoms

We used the Center for Epidemiological Studies Depression Scale (CES-D). The CES-D is a self-administered rating scale developed by the United States National Institute of mental Health for the purpose of investigating the prevalence of depressive symptoms in the general population. The highest possible total score is 60; a score of 16 points or higher suggests the presence of clinical depressive symptoms. Subjects demonstrating a score of 15 points or less were classified as ‘not having depressive symptoms' and those exhibiting a score of 16 points or higher were classified as ‘having depressive symptoms' (27).

Statistical methods

The Shapiro-Wilk test was used to examine the distribution of the data. Non-normally distributed data were analyzed using nonparametric tests. Differences between the Slope and Non- Slope groups were assessed using univariate the unpaired t tests, the Mann-Whitney U test and the Chi- square test. Next, a logistic regression analysis was carried out. Factors founds significant at p<0.20 in univariate analysis were included in the logistic regression model. The odds ratio (OR) associated with each factors, the 95% confidence interval for the OR, and the p value were reported. All analyses were performed with the PASW software package, version 18 (SPSS, Japan Inc., Tokyo, Japan). A 2-tailed value of p < 0.05 was considered statistically significant.

Results

The characteristics of both groups are shown Table 1. Significant differences were not observed in both groups. The comparison of physical activity levels in the two groups is shown in Figures 1 and 2. The Slope group had significantly fewer steps and less minutes per day being active (p < 0.001) than did the Non-Slope group. Furthermore, HF %predicted (p < 0.01) was significantly lower in the Slope group. However, QF %predicted (p < 0.01) in the Slope group was significantly higher than in the Non- Slope group. In addition, there were significantly more women with depression (CES-D scale score ≥16) in Slope group (p < 0.05). There were no significant differences between the groups in pulmonary functions.

Table 1.

Characteristics in the Slope and Non-Slope groups

	Slope group N=43	Non-Slope group N=65	P value
Age (years)	76.7 ± 5.0	76.6 ± 5.0	0.92
Height (cm)	151.1 ± 5.2	152.8 ± 6.6	0.27
Weight (kg)	52.0 ± 9.0	52.2 ± 8.9	0.31
BMI (kg/m2)	22.8 ± 3.7	22.6 ± 3.3	0.47
Education level (%)
Junior high school	17 (39.5)	26 (40.0)
High school	19 (44.2)	30 (46.2)	0.54
Above	7 (16.3)	9 (13.8)
Live alone (%)	18 (40.9)	28 (43.1)	0.34
Number of comorbidity (%)
None	4 (9.3)	6 (9.2)
1	8 (18.6)	12 (18.5)
2	14 (32.6)	19 (29.2)
3	11 (25.6)	17 (26.2)	0.191
4	2 (4.7)	5 (7.6)
5	3 (7.0)	4 (6.2)
6 or more	1 (2.2)	2 (3.1)

BMI: body mass index; Values are presented as mean ± standard deviation, or number (%); Slope group versus Non–Slope group difference: Unpaired t- test, Mann-Whitney U test, Kruskal Wallis test and Chi-square test

Figure 1.

Comparison of Physical activity (mean activity counts) between Slope group and Non -Slope group (p<0.001)

A logistic regression model that included number of comorbidity, FEV₁, HF, QF, depression suspicion, activity counts and activity time per day demonstrated that HF (OR 0.666, 95%CI 0.558-0.796), depression suspicion (OR 1.093, 95%CI 1.019-1.427), activity counts per day (OR 0.779, 95%CI 0.715-0.841) and activity times per day (OR 0.821, 95%CI 0.801-0.913) were significant factors associated with living slope ground.

Table 2.

Outcomes for Slope and Non-Slope groups

	Slope group N=43	Non-Slope group N=65	P value
Pulmonary function
FEV1 (l)	1.69 ± 0.41	1.76 ± 0.48	0.09
FEV1 % predicted (%)	101 ± 18	100 ± 19	0.36
FVC (l)	2.18 ± 0.48	2.15 ± 0.47	0.37
VC (l)	2.32 ± 0.47	2.35 ± 0.67	0.28
FEV1/FVC (%)	78 ± 8	79 ± 8	0.43
Muscle force
HF (kg)	19.3 ± 4.8	27.2 ± 6.1	< 0.05
HF %predicted (%)	82 ± 19	93 ± 15	< 0.01
QF (kg)	22.7 ± 4.7	19.3 ± 5.7	< 0.05
QF %predicted (%)	83 ± 18	72 ± 22	< 0.01
CES-D
≥16	13 (30.2%)	6 (9.2%)
<16	38 (69.8%)	59 (90.8%)	< 0.05

Values are presented as mean ± standard deviation; FEV₁: forced expiratory volume in 1 second; FVC: forced vital capacity; VC: vital capacity; FEV₁/FVC: forced expiratory volume in 1 second/forced vital capacity; HF: handgrip force; QF: quadriceps force; CES-D the Center for Epidemiological Studies Depression Scale; Slope group versus Non–Slope group differences: Unpaired t-test, Mann–Whitney U test and Chi-square test

Discussion

We have conducted what is, to our knowledge, the first study to date that objectively measures the association between the environmental factor of residential location and physical functioning, including physical activity, in elderly women. We found that elderly women living in sloped locations had lower physical activity, HF and higher rates of depression as measured by the CES-D. These findings support the importance of considering differences in location when making recommendations on exercise for community-dwelling elderly women.

Table 3.

Independent determinants in Slope and Non-Slope groups

Variables	B	SE	OR(95% CI)	P value
Number of comorbidity	-0.235	0.207	0.966 (0.643-1.450)	0.866
FEV1	0.851	0.763	1.341 (0.525-9.449)	0.265
HG	-1.406	0.091	0.666 (0.558-0.796)	0.000
QF	0.074	0.048	1.177 (0.980-1.183)	0.126
CES-D
≥16	-0.092	0.042	1.093 (1.019-1.427)	0.044
<16
Activity counts	-2.001	0.102	0.779 (0.715-0.841)	0.002
Activity times	-0.189	0.013	0.821 (0.801-0.913)	0.004

FEV₁: forced expiratory volume in 1 second; HF: handgrip force; QF: quadriceps force; CES-D the Center for Epidemiological Studies Depression Scale

The major strengths of this study are that we have precisely defined a specific and relevant factor in the residential environment and have used objective measures of physical functioning and physical activity. The physical activity levels of elderly women living in flatter locations were higher than those of elderly women living in more sloped locations. The majority of the literature indicates that there are positive relationships between neighborhood environment characteristics (e.g., street connectivity and access to recreational facilities) and physical activity among older adults (28, 29, 30). In our study, in support of only one previous research hills employed were associated with lower physical activity (16). It is relative with that, King CC et al reported that after multivariate adjustment there were significant correlations between lower physical activity and lack of hills (18). It may seem contradictory that the presence of hills was positively associated with physical activity. We considered that this may be caused by data provided using a questionnaire. Because of that test-retest kappa values for these environmental characteristics were not in the excellent range (31). In addition, elderly women in flatter locations demonstrated greater HF than did their counterparts in sloped locations. This finding is in line with data that have shown a positive association between physical activity levels and muscle strength (32, 33, 34). In support of previous findings this study found that grip strength was significantly associated with slope ground in their strength of association with physical activity. This study of neighborhood-level geographic factors among older women indicates that such factors can affect the older population's functioning and physical activity. A awareness that slope ground influences on physical activity and HF should be used to specifically target health promotion in elderly women and the older old, including promoting physical function for as long as possible. However, elderly women in flatter locations exhibited lower QF scores than did women in sloped locations. Stair-stepping and walking on sloped terrain present a greater load to leg muscles than walking on level ground, and elderly women in the slope locations appear to demonstrate a training effect of this additional load. Regular exercise and the use of some specific training programs are powerful stimuli for improving and maintaining muscle mass and strength during the aging process (35). However elderly women living in sloped locations had lower physical activity levels. Therefore, we were not able to determine the reasons for the different relationships between sloped location and QF scores in this study. In addition, it seems important to say a little about the importance of our finding that women in sloped locations had lower levels of physical activity and higher levels of depression. In this study, we could not clear mechanism that slope ground directly and indirectly affect participation in depression. In support of previous studies, their studies found that the relationship between physical activity and depression (19, 20, 21, 22, 36). Older women who live in sloped areas may be reluctant to go outside of their homes very often. Perhaps this is a source of depression. Although older women will improve their physical activity by getting out and walking on the sloped ground, they may not do so very often because it is more difficult than if the ground were flat. The majority of the literature indicates that inactivity among elderly people could cause depression, anxiety and chronic diseases (37, 38, 39, 40, 41). Although we have demonstrated that the factor of slope is related to physical functioning and the level of physical activity, such a factor may be importance like aging. This finding indicates that policy and practice need to both be aware that those with mental health issues tend to have depression and facilitate intervention to decrease depression within this group.

The present study has several limitations. First, the number of subjects was small. Second, the findings may not be applicable to older women in more diverse prefectures in Japan because this sample was predominantly residents of Nagasaki, where health awareness tends to be relatively high. Also, the physical activity measure did not differentiate between walking and stair-stepping. If separate measures of walking and stairstepping had been available, we might have been able to detect and clarify the influence that the sloped environment has on physical functioning and physical activity.

In conclusion, the factor as sloped location may significantly decrease in older women with lower physical activity and grip strength and depressive symptoms. Moreover, these women were more likely to be depressed. Since there was a relationship between living location and lower functional status and depressive symptoms, a comprehensive geriatric assessment, related to all aspects of older women, is recommended. It is important that when we develop interventions for the purpose of improving physical activity for community-dwelling elderly women, we take such factors in the residential environment into account.

Acknowledgments: We thank the study participants, technical staff, administrative support team, and our co-workers for their help. In addition, we are grateful to Sue Jenkins, PhD, from the Lung Institute of Western Australia (Perth, Western Australia) for assistance with reviewing this manuscript. This study was supported by the Local Elderly Care Management Center, and the Special Elderly Nursing Home Keijyuen.

Conflict of Interest: The authors declare no potential conflicts of interest relevant to this article.