In a Statistics Canada study released Wednesday, researchers found that quitting smoking or cutting back on the number of daily cigarettes were the changes most commonly reported, although most smokers continued the habit after their diagnosis.
"Studies have shown that there are positive benefits in terms of longevity, quality of life and reducing recurrence or progression of a disease," said Pamela Ramage-Morin, a senior analyst at Statistics Canada and a study co-author.
"But I don't think it's as simple as just saying: 'Well, people just can't be bothered. Why wouldn't they (make changes) when they get such a wake-up call?'" she said Wednesday from Ottawa.
In previous research, survey subjects have reported a number of barriers to making lifestyle changes that would improve their health.
"They often said things like they were too tired or their illness was preventing them from doing so," said Ramage-Morin, referring to increasing physical activity.
A stroke, for instance, could lead to paralysis on one side of the body, she said. "So if there's mobility or a disability issue that results from the condition, then clearly that's a barrier to making change to becoming physically active."
People taking medications for their condition may also suffer side-effects that make exercise difficult, she added. That can be particularly true for older people, who often must take multiple prescription and over-the-counter drugs.
In the 12-year study, which followed more than 5,000 Canadians aged 50 and older from 1994-1995 to 2006-2007, those diagnosed with diabetes or cancer were the most likely to make behaviour changes, although the lifestyle improvements were modest overall.
Participants who developed diabetes accounted for the biggest changes: they reduced smoking, drank less alcohol, exercised more, and ate more fruit and vegetables.
But those who developed a respiratory disease like chronic bronchitis or emphysema reported little alteration in smoking behaviour or eating habits, and they also became less physically active. Their only noticeable behaviour change was a reduction in excessive drinking.
The finding that a high percentage of those with respiratory disease continued to smoke may seem surprising, but Ramage-Morin said it's possible that many of these people were more likely to be smokers in the first place and could be more severely addicted to nicotine.
Twenty-five per cent of those with lung and/or airway disease were smokers before their diagnosis, "and that didn't change substantially, nor did the average number of cigarettes that they smoked each day," she said.
"The bad news there is that three-quarters of the people who smoked prior to diagnosis continued to smoke afterwards."
The study looked at five chronic conditions — heart disease, cancer, stroke, respiratory disease and diabetes — which are among the leading causes of death in Canada. Worldwide, these disorders account for 60 per cent of all deaths, but are considered largely preventable with healthier lifestyle habits.
Ramage-Mortin said chronic conditions are more common as people age, and with the baby-boom generation entering retirement age, the proportion of Canadians with such disorders will go up dramatically.
"So we know that there are probably going to be a lot more people with chronic conditions living in our community," she said.
"I think what this study can demonstrate is there are things we can do individually and ... and as a community to manage these chronic conditions, so that we increase longevity but increase quality of life at the same time and potentially stop these conditions from progressing."