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Age and Ageing Advance Access originally published online on May 30, 2008
Age and Ageing 2008 37(4):449-454; doi:10.1093/ageing/afn114
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Copyright © The Author 2008. Published by Oxford University Press on behalf of the British Geriatrics Society.

Psychosocial predictors of physical activity in older aged asthmatics

Shilpa Dogra, Brad A. Meisner and Joseph Baker

Lifespan Health and Performance Laboratory, York University, North York, ON, M3 J 1P3, Canada

Address correspondence to: Shilpa Dogra. Tel: +1(416) 736-2100; ext. 20553; Fax: +1(416) 736-5774. Email: shilpad{at}yorku.ca


   Abstract
Top
 Abstract
Background
 Methods
 Results
 Discussion
 Conclusion
 Key points
 Conflict of interest
 References
 
Background: there is little information available on physical activity (PA) patterns and the psychosocial determinants of PA in older adults with asthma.

Objective: to quantify the prevalence of PA in older asthmatics and to explore the potential psychosocial determinants of PA in this population.

Study Design and Setting: cross-sectional data available from the Canadian Community Health Survey (CCHS), cycle 2.1, were used. There was a total of 1,772 older asthmatics in the sample.

Results: there were significant differences in the prevalence of PA between older asthmatic females compared to middle-aged asthmatic females ({chi}2 = 23.65, P < 0.0001) and older asthmatics compared to older non-asthmatics ({chi}2 = 38.1, P < 0.0001). Logistic regression revealed a significant association between PA and perceived health in older asthmatic males (OR = 5.39, CI = 1.36–21.33) and females (OR = 4.81, CI = 1.41–16.38). Being a member of a volunteer organisation was also significantly associated with PA in older asthmatic females (OR = 1.59, CI = 1.11–2.30).

Conclusion: older asthmatics were less active than their non-asthmatic peers. Perceived health was an important predictor of PA in both older asthmatic males and females. Exercise interventions in this population should make an effort to improve self-perceived health.

Keywords: asthma, physical activity, aged, middle aged, elderly, psychosocial factors


   Background
Top
 Abstract
 Background
Methods
 Results
 Discussion
 Conclusion
 Key points
 Conflict of interest
 References
 
The age demographic of Canada is currently undergoing a shift as a result of ageing baby boomers. It is expected that by 2011, 15% of the Canadian population will be over the age of 65[1]. This raises many concerns for the health care system, as chronic diseases are more likely to manifest in this age period. Despite the many benefits of physical activity (PA) and exercise in chronic disease prevention and treatment, older adults remain the most sedentary segment of the population[2].

Asthma is a chronic respiratory disease that affects over 7% of older adults in Canada[3]. Asthma symptomatology has been shown to benefit from PA and exercise[4] and is noted to be an important component of asthma control and management[5]. However, similar to older adults, asthmatics also have lower rates of PA[6].

Older adults have many barriers associated with initiating and maintaining PA. Past research has predominantly studied physical or environmental barriers[7]. Research pertaining to the determinants of PA in asthmatics is limited to children[8, 9] and mainly focuses on asthma symptomatology as a barrier[10]. The psychosocial determinants of PA in older aged asthmatics are largely unknown. In addition, the proportion of physically active older adults with asthma has never been quantified. Thus, the purpose of this research was 2-fold: (i) to determine whether older adults with asthma are less active than older non-asthmatic adults or middle-aged adults with asthma and (ii) to explore the potential psychosocial determinants of PA in this population.


   Methods
Top
 Abstract
 Background
 Methods
Results
 Discussion
 Conclusion
 Key points
 Conflict of interest
 References
 
Participants
Data from the Canadian Community Health Survey (CCHS; cycle 2.1), a nationally representative population-based cross-sectional survey were used. The CCHS collects information on the health status, health-care use, and health determinants of Canadians. Detailed information on survey sampling methods can be found in the CCHS user guide. All respondents provided informed consent prior to participating and were informed of the survey's objectives. Cycle 2.1 was collected in 2004 and was the most current cycle available at the time of analysis.

Variables
Older adults included males and females between the ages of 65–79 years and middle-aged adults included males and females between the ages of 45–64 years. These age groups were selected on the basis of the National Library of Medicine, Medical Subject Headings[11]. Adults over the age of 80 were not included (NI) in the analysis as there were a small number of asthmatics once stratified by sex (M = 153, F = 347). Physician-diagnosed asthma was self-reported as ‘yes’, ‘no’, ‘refusal’ and ‘do not know’. The latter two categories were not included in the analysis. Estimated energy expenditure was calculated on the basis of self-reported leisure-time physical activities; a PA index was then created to classify participants as ‘active’ (≥1.5 kcal/kg/day) or ‘inactive’ (< 1.5 kcal/kg/day).

Psychosocial determinants of PA included self-perceived health, self-perceived mental health, satisfaction with life in general, self-perceived stress, sense of belonging to community, member of a volunteer organisation, mood disorder, anxiety disorder, and other physical/mental health conditions. All of these determinants were measured using single item scales. Self-perceived health and self-perceived mental health were rated as either ‘excellent’, ‘very good’, ‘good’, ‘fair’ or ‘poor’, whereas satisfaction with life, in general, was rated as ‘very satisfied’, ‘satisfied’, ‘neither satisfied nor dissatisfied’, ‘dissatisfied’ or ‘very dissatisfied’. These three variables were included as they have been shown to significantly influence PA levels in adults with asthma[12]. Self-perceived stress was included because stress has been shown to induce breathlessness in adults with asthma, thereby exacerbating symptoms and possibly compromising PA levels[13]. It was measured on a scale of 1 to 5; 1 being ‘not at all’ and 5 being ‘extremely’. Sense of belonging to the community was rated as either ‘very strong’, ‘somewhat strong’, ‘somewhat weak’ or ‘very weak’ and was essential to include as it has been demonstrated to be a direct predictor of PA in retirees[14]. The questions, member of a volunteer organisation, mood disorder, anxiety disorder, and other physical/mental health conditions included ‘yes’ or ‘no’ responses. Participating in a volunteering programme has been shown to increase PA levels in older adults[15] and was therefore considered to be an important measure for this study. Mood and anxiety disorders were included because of their strong associations with asthma[16] and PA[17].

Marital status, body mass index (BMI), education, functional limitations, and cultural/ethnic origin were included as covariates. Marital status was classified in one of four categories: ‘married’, ‘common law’, ‘widowed/divorced/separated’, and ‘single’. Marital status was included as a covariate because of its established association with health in older adults[18]. BMI (kg/m2) was a continuous variable derived from self-reported height and weight, which was then coded into BMI categories: underweight (> 18.5 kg/m2), normal weight (18.5–24.9 kg/m2), overweight (25–29.9 kg/m2), and obese (≥30 kg/m2). Education level was used to account for socioeconomic status. Highest level of education was reported as ‘less than secondary school graduation’, ‘secondary school graduation, no post-secondary education’, ‘some post-secondary education’, and ‘post-secondary degree/diploma’. Functional limitations were categorised as ‘sometimes’, ‘often’ or ‘never’. Finally, participants were asked to specify their cultural or ethnic background, which was subsequently dichotomised into ‘white’ and ‘non-white’.

Statistical analysis
All analyses were performed using SPSS 15.0. To accurately estimate the measures of variance, the population weights were rescaled, standardised, and then re-applied to the sample. Data were weighted as per the master weight in order to ensure representation of the Canadian population.

Univariate analyses were performed for all covariates. Chi-squares and standardised adjusted residuals were used to test for differences between PA levels of older asthmatics compared to middle-aged asthmatics and older non-asthmatics. These were then converted into percentages and represented graphically. Multiple logistic regression analysis was used to calculate the odds ratios (OR, 95% CI) for PA in older asthmatic males and older asthmatic females separately. All psychosocial variables were loaded into the model. Variables that were significant in the fully loaded model were then entered into a new regression analysis in order to create the final parsimonious regression model. All regressions were adjusted for the aforementioned covariates.


   Results
Top
 Abstract
 Background
 Methods
 Results
Discussion
 Conclusion
 Key points
 Conflict of interest
 References
 
Table 1 outlines the statistical differences for the descriptive characteristics of the three groups. As expected, there were significant differences in functional limitations between the middle-aged asthmatics and older asthmatics such that fewer middle-aged asthmatics responded with ‘often’ and fewer older asthmatics responded with ‘never’. Similarly, there were significant differences between marital status when comparing older asthmatics to middle-aged asthmatics but not for older asthmatics to older non-asthmatics.


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  		Table 1. Characteristics of middle-aged asthmatic and older non-asthmatic adults compared to older asthmatic males and females

 
Figure 1 illustrates the significantly higher proportion of active middle-aged asthmatic females (both sexes: {chi}2 = 20.33, P < 0.001, males: {chi}2 = 0.11, P = 0.75 and females: {chi}2 = 29.57, P < 0.001) and active older non-asthmatics (both sexes: {chi}2 = 38.1, P < 0.001, males: {chi}2 = 11.00, P = 0.001 and females: {chi}2 = 23.65, P < 0.001) when compared to older asthmatics.


Figure 1
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  		Figure 1. (a) Proportion of active middle-aged asthmatics and active older asthmatics panel (b): Proportion of active older non-asthmatics and active older asthmatics

 
The fully loaded logistic regression model revealed that self-perceived health was the only significant predictor of PA in older asthmatic males. Self-perceived health, self-perceived stress, and being a member of a volunteer organisation were all significant predictors of PA in older asthmatic females; however, in the final parsimonious model, self-perceived stress became non-significant. Table 2 contains details of the significant predictors of PA adjusted for marital status, BMI, education, functional limitations, and cultural/ethnic origin. Significant associations between PA and mental health status or cultural/ethnic origin were not found and were therefore NI in Table 2. Results indicate that older asthmatic males with ‘excellent’ self-perceived health are 5.39 times more likely to be physically active than older asthmatic males with ‘poor’ self-perceived health and older asthmatic females with ‘excellent’ self-perceived health are 4.81 times more likely to be physically active than older asthmatic females with ‘poor’ self-perceived health. Furthermore, females who were members of a volunteer organisation were 59% more likely to be physically active than those who were not. For older asthmatic females, education (less than secondary school graduation), BMI (normal and overweight) and functional limitations (often) were significant predictors of PA, whereas in older asthmatic males only education (less than secondary school graduation and some post-secondary education) and functional limitations (often) were significant predictors of PA.


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  		Table 2. Significant predictors of physical activity in older asthmatics (parsimonious regression model)

 

   Discussion
Top
 Abstract
 Background
 Methods
 Results
 Discussion
Conclusion
 Key points
 Conflict of interest
 References
 
In a nationally representative cross-sectional sample of the Canadian population, we found that older asthmatics were less active than older non-asthmatics and that older asthmatic females were less active than middle-aged asthmatic females. Moreover, we found that self-perceived health was an important predictor of PA in older asthmatics.

The observed differences between PA levels of older asthmatics and older non-asthmatics were as expected. Adults with chronic respiratory illnesses have been shown to be less active than their age-matched peers[19], which may be the result of associated functional limitations[20] and perceived barriers to PA[10]. The differences seen between males and females when comparing PA levels of middle-aged asthmatics and older asthmatics in our study were somewhat atypical; older asthmatic males and middle-aged asthmatic males had similar activity levels, whereas older asthmatic females were less active than middle-aged asthmatic females. Canadian statistics show that older adults, both male and female, are in fact, less active than younger adults[21]. However, studies have shown an increase in both exercise participation and sedentary activities upon retirement[22] while studies measuring net activity levels (i.e. accounting for work-related activity and leisure-time PA) have found decreases in the level of activity upon retirement[23]. The discrepancy observed between males and females in our study may be the result of changes in work-related PA and leisure-time PA levels after retirement, with greater decreases in work-related activity in women, specifically, work-related transportation (e.g. walking to work)[23]. Unfortunately, the CCHS does not contain information on work-related activity; therefore, we were unable to further investigate this notion.

To our knowledge, this is the first study to examine psychosocial predictors of PA in an older aged population of asthmatics. The most robust finding is that perceived health was a significant predictor of PA in both male and female older asthmatics. Our results indicate that older asthmatic males with ‘excellent’ self-perceived health are 5.39 times more likely to be physically active than older asthmatic males with ‘poor’ self-perceived health, and older asthmatic females with ‘excellent’ self-perceived health are 4.81 times more likely to be physically active than older asthmatic females with ‘poor’ self-perceived health. In fact, the results suggest a potential dose-response relationship between self-perceived health and PA, particularly in older asthmatic females. Our results are consistent with previous research that examines the role of PA and self-perceived health in adults with chronic diseases. Perceived health has been shown to be an important predictor of PA and exercise levels in individuals with chronic disease and disabilities such that being active decreases the odds of reporting ‘poor’ versus ‘excellent’ health[24]. The reciprocal relationship has also been studied. In a study of Japanese men 50–59 years, Okano et al. [25] found that leisure-time PA was the only significant predictor of self-perceived health. Finnegan et al. [26] found that comorbidity, lack of vigorous PA, and smoking were clear markers for poorer levels of self-rated health in a population of mid-life adults with chronic illnesses. Furthermore, a previous study found that greater PA involvement in Canadian adult asthmatics was associated with better self-reported health i.e. physically active asthmatics had significantly greater self-perceived health, greater self-perceived mental health, fewer chronic conditions, fewer functional limitations, and greater satisfaction with life, in general[12]. The relationship between self-perceived health and PA is so strong that changes in PA levels have been noted to change self-perceived health status[27]. This further supports the dose–response association between perceived health and PA found in our study. It is important to note that although a strong association exists between PA and perceived health, the cross-sectional nature of the CCHS does not allow us to claim a causal relationship between the two variables.

We also found that older asthmatic females who were members of a volunteer organisation were 59% more likely to be physically active compared to those older asthmatic females who were not volunteering, adjusting for all other variables in the model. This is congruent with previous research showing that social variables are more important in predicting the PA levels in females, whereas environmental variables are of greater relevance in males[28]. It is surprising, however, that no other psychosocial factor was significantly associated with PA in this sample. A study conducted by Wainwright et al. [29] found that psychosocial factors cluster among older adults with asthma, and that there is a cooccurrence of psychosocial adversity with asthma. Our finding may be the result of a strong influence of perceived barriers associated with having asthma. For example, a study conducted by Mancuso et al. [14] on adult asthmatics found that most patients reported asthma-associated limitations in daily activities as well as work and leisure-time activities. The authors concluded that asthma was a deterrent to PA.

Adults have been shown to possess ‘excellent’ and ‘very good’ self-perceived health despite having a chronic disease[23]. Therefore, not all individuals perceive disease as a barrier. Asthmatics have the ability to be active and exercise without severe limitations, provided they take necessary precautions. It is, therefore, imperative that older asthmatics are informed regarding basic preventive measures associated with exercise-induced asthma and management of asthma attacks during PA. The findings of this study suggest that PA and exercise interventions targeting older asthmatics should focus on increasing self-perceived health. The aforementioned educational interventions would likely accomplish this goal. In addition, assisting older asthmatics with accomplishing basic PA and exercise goals may assist them in realising that their disease is not a disability, thereby increasing self-perceived health. Given the importance of PA in the prevention of chronic diseases such as hypertension and type II diabetes, as well as in the management of asthma, it is pertinent that PA levels are increased in this growing segment of the population. It is also of great importance that primary care physicians prescribe PA and exercise to older asthmatics, as physician support is a recognised facilitator of initiating PA in asthmatics[14] and in older adults[30].

Limitations
Although a large population-based sample that is generalisable to all Canadian asthmatics was used, there are some notable limitations to our study. First, the CCHS uses self-reported data; therefore, variables such as BMI and PA are subject to response bias. Furthermore, the self-reported health variables may not have been sensitive enough to detect specific health issues. Future research should consider more specific and objective measures of health. Second, because this was a cross-sectional study, we were unable to exclude the possibility of reverse causality. Third, it is possible that the severity of asthma or baseline lung function played a role in the PA levels reported by this cohort. Unfortunately, the CCHS does not contain either of these variables and we were therefore unable to stratify our analyses. Fourth, our sample of asthmatics and non-asthmatics may include individuals with other chronic diseases. In addition, asthmatics have been shown to have higher rates of chronic pulmonary disease, heart disease, and allergies. Therefore, it is possible that our results were influenced by the presence of other chronic conditions. Finally, it is possible that this older cohort is not representative of the actual population in the instance that older participants who are suffering from ill health (cognitive, functional, and/or physical) are less likely to participate. This may generate a healthier sample leading to selection bias, and as a result, the odds ratios in this study may be a more conservative estimate.


   Conclusion
Top
 Abstract
 Background
 Methods
 Results
 Discussion
 Conclusion
Key points
 Conflict of interest
 References
 
In conclusion, we found that older asthmatics were less active than their age-matched peers and older asthmatic females were less active than middle-aged asthmatic females. Moreover, self-perceived health was a significant predictor of PA in this population; therefore, exercise interventions targeting older asthmatics should focus on increasing self-perceived health.


   Key points
Top
 Abstract
 Background
 Methods
 Results
 Discussion
 Conclusion
 Key points
Conflict of interest
 References
 

  • Little is known of the psychosocial determinants of PA in older asthmatics.
  • We found that older asthmatics are less active than older non-asthmatics and that older females with asthma are less active than middle-aged female asthmatics.
  • Self-perceived health is an important predictor of PA levels in older adults with asthma and hence integral to exercise and PA programmes targeting this population.


   Conflict of interest
Top
 Abstract
 Background
 Methods
 Results
 Discussion
 Conclusion
 Key points
 Conflict of interest
References
 
No conflicts of interest.


   References
Top
 Abstract
 Background
 Methods
 Results
 Discussion
 Conclusion
 Key points
 Conflict of interest
 References
 

  1. Statistics Canada. Median age reaches all-time high. (2007) Accessed on July 16, http://www12.statcan.ca/english/census01/Products/Analytic/companion/age/canada.cfm.
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  21. Statistics Canada. CANSIM, table 105–0433 and Catalogue no. 82-221-X. Last modified: 2007-04-30 (2007) http://www40.statcan.ca/l01/cst01/health46.htm (last accessed 18 June 2007).
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Received 26 July 2007; accepted in revised form 15 February 2008.


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