Health behaviour changes after diagnosis of chronic illness among Canadians aged 50 or older
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Heart disease, cancer, stroke, respiratory disease and diabetes are among the leading causes of death in Canada.1 Worldwide, these chronic conditions account for 60% of all deaths.2 Since they are influenced by modifiable behaviours, they are considered largely preventable.3,4 For people with a chronic illness, adopting a healthier lifestyle, such as smoking cessation, increased physical activity, eliminating heavy alcohol consumption and improving diet, can extend longevity, reduce the recurrence of an event and enhance quality of life.5-7
Population-level information about lifestyle changes among people diagnosed with chronic conditions is lacking. Previous studies have examined behaviour change among small samples of individuals with a specific condition, and many studies have been based on retrospective accounts.8,9 As well, most research on secondary prevention has taken place in the United States where access to health care and behaviour modification programs is variable. Only a handful of studies have been conducted in Europe or Australia where access to health care is more universal.10,11 A literature review did not reveal any studies that used population-based data for Canada.
The present analysis examines changes in smoking, physical activity, alcohol consumption and diet in a representative sample of Canadians aged 50 or older diagnosed with a major chronic condition (see The data). Based on prospective design, in which behaviours are assessed before and after the diagnosis, the study avoids potential biases from retrospective accounts of post-diagnosis behaviour change.
Smoking cessation was the most commonly reported behaviour change—the percentage of people who smoked decreased significantly following the diagnosis of heart disease, diabetes, cancer and stroke (Table 1). Among people with heart disease, for example, the prevalence of smoking declined from around 14% to less than 11%. Those diagnosed with respiratory disease were the exception―not only were they more likely to smoke before diagnosis (25%), but there was no significant decrease in the percentage who were smokers after diagnosis.
Table 1 Prevalence of health behaviours pre- and post-diagnosis of selected chronic conditions by sex and age group, household population aged 50 or older, Canada, 1994/1995 to 2006/2007
Except for those with respiratory disease, smokers' daily cigarette consumption fell significantly (Figure 1). This decline in smoking may, in part, be due to the new diagnosis, but it may also reflect a community-wide trend—even among the healthy comparison group, the percentage of current smokers (N = 1,103) decreased slightly over the two-year period from 23% to 21% (p < .05). However, regardless of the chronic condition, the majority (approximately 75%) of those who smoked continued to do so after diagnosis (Table 1).
Figure 1 Mean number of cigarettes smoked per day, pre- and post-diagnosis of chronic condition, current smokers aged 50 or older, Canada, 1994/1995 to 2006/2007
Leisure-time physical activity
Only people with diabetes reported a post-diagnosis increase in leisure-time physical activity. Initially, close to 50% of this population engaged in physical activity at least three times a week; after diagnosis, the figure was about 56%. In addition, only among people diagnosed with diabetes did average energy expenditure change significantly: from 1.1 to 1.4 kcal/kg/day (p < .001). Although significant, this increase is not large. Also, it was people aged 50 to 64 with diabetes who tended to become active; seniors were less likely to increase their activity.
And among people diagnosed with respiratory disease, the percentage who were physically active fell from 52% to 44%. Again, age was a factor, as seniors were more likely to become inactive post-diagnosis than were 50- to 64-year-olds.
This was in contrast to the pattern of physical activity among the healthy comparison group. Initially, this group (N = 1,053) was more likely to be physically active during leisure-time, and their likelihood of being active rose over the two-year period from 58% to 63% (p < .05).
Fear or concern that physical activity might be dangerous could be a deterrent for individuals with chronic conditions, particularly, heart-related ailments. However, for clinically stable patients without ischemia, exercise under the supervision of a physician has less risk than sedentary behaviour.30
Following a diagnosis of a chronic condition, individuals' alcohol consumption tended to decrease. For example, among those diagnosed with diabetes, the percentage who drank excessively (more than 2 drinks per day or more than 14 drinks a week for men; more than 2 drinks per day or more than 9 drinks a week for women) fell from about 10% to 5% (Table 1). Among those with respiratory disease, the prevalence of excessive drinking declined from almost 13% to 8%. Current drinkers diagnosed with cancer or stroke averaged significantly fewer drinks each week (Figure 2).
Figure 2 Mean number of alcohol drinks consumed per week, pre- and post-diagnosis of chronic condition, current drinkers (past 12 months) aged 50 or older, Canada, 1994/1995 to 2006/2007
Alcohol consumption among the healthy comparison group remained stable over the study period—16% drank excessively, 55% drank moderately, and 29% abstained or drank very little.
Fruit and vegetable consumption
Before they were diagnosed, the percentage of the study population who averaged five or more servings of fruit and vegetables a day ranged from 27% 42%. No significant post-diagnosis increases emerged in the percentages eating the minimum number of servings, although among those with diabetes, the average daily number of servings rose from 4.4 to 5.2 (p < .01). The fruit and vegetable intake of the healthy comparison group did not change over the study period, with approximately 32% consuming five servings a day.
Secondary prevention can improve longevity, enhance quality of life, and reduce medical expenses. This study reveals that people rarely made positive changes in lifestyle behaviours after they had been diagnosed with a chronic condition. Smoking cessation and reductions in the number of cigarettes smoked were the changes most commonly reported, but the vast majority of smokers continued to smoke.
People with diabetes were the most likely to report positive behaviour changes, although the improvements were modest. Those diagnosed with diabetes reduced smoking and excessive drinking and increased their leisure-time physical activity and fruit and vegetable consumption. By contrast, people diagnosed with respiratory disease reported no change in smoking or fruit and vegetable consumption, and were less likely to be physically active. Over the same period, a reduction in excessive drinking was the only change in health behaviours reported for this group.
This work was supported by a grant from the U.S. National Institutes of Health: National Institute on Aging R01 AG034211 (J. T. Newsom). We thank Jillian Oderkirk, Adrianne Feldstein, Javier Nieto, and Victor Stevens for helpful feedback at earlier stages of this paper.
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