A study published in the Canadian Medical Association Journal (CMAJ) said that more than one third of Canadians who died by drowning had a pre-existing medical condition.
One part of the study urged caution before people are told to do swimming or aquafit activity for better health.
The study was carried out by Cody L. Dunne, Julia Sweet and Tessa Clemens; researchers in the faculties of medicine at the University of Calgary, the University of Ottawa and the Drowning Prevention Research Centre in Toronto. Their study was done by analyzing data from the 10-year period from 2007 to 2016.
The report said during that time, 4288 people died in Canada from drowning. The study said more than 43 per cent of those victims had a pre-existing medical condition.
Drowning occurred more frequently in people with ischemic heart disease (narrowed arteries) and seizure disorders, but less frequently in people with respiratory disease. One item the study noted is that females aged 20 to 34 years with a seizure disorder had 23 times a greater risk of drowning than those of the same age and gender with no disorders.
Also, in general drowning occurred more often while people were bathing or alone. Drowning was also less often in males, or in those who had used alcohol, than among those with pre-existing medical conditions, said the report.
In its interpretation, the study said the risk of fatal drowning is increased in the presence of some pre-existing medical conditions. Tailored interventions aimed at preventing drowning based on pre-existing medical conditions and age are needed. Initial prevention strategies should focus on seizure disorders and bathtub drownings.
All that being said, the study also quoted findings from the Lifesaving Society Canada by the Drowning Prevention Research Centre.
That organization published a report in 2018 that showed the number of drowning deaths in Canada was on the decline in a 25 year period from 1991 to 2015.
"Despite this long-term progress, high numbers of preventable water-related fatalities continue to occur in Canada: a total of 2,262 people lost their lives in Canadian waters between 2011 and 2015," said the Lifesaving Society.
The CMAJ study said that identifying and addressing known risk factors will help save lives.
"For example, after research showed a considerable proportion of child drownings occurred in unsecured household pools and the effectiveness of pool fencing at reducing these deaths, legislative changes were introduced in Quebec," said the study.
CMAJ also reported that overall the data is limited on pre-existing medical conditions and drownings, usually because of small sample sizes and narrow focus on certain conditions such as autism spectrum disorder and epilepsy, or being age specific such as focusing on children.
"The association between various pre-existing medical conditions and drowning in different age groups is not well understood. This information could assist with the development of targeted drowning prevention strategies and prioritizing of resources spent on prevention," said the study.
It also reported that the majority of Canadians have a medical condition that could be an issue.
"Forty-four percent of Canadian adults have at least one chronic disease, which suggests that millions of Canadians with conditions that potentially impair their heart, lungs or brain participate in water activities," said the study.
But at the same time, "swimming and aquatic fitness is often encouraged" for those with chronic illness to promote better health. The study urged caution in this respect.
"The public and physicians should be aware of pre-existing medical conditions that might place people at a higher risk of drowning, so that appropriate precautions can be taken to ensure safety while participating in aquatic activities," said the study.
