One in 3 people who drowned in Canada had a pre-existing medical condition that contributed to the death in almost half the cases, according to new research in CMAJ (Canadian Medical Association Journal) https://www.cmaj.ca/lookup/doi/10.1503/cmaj.211739.

The study analyzed all 4288 unintentional drownings in both children and adults over 10 years from 2007 through 2016 in Canada. Researchers found that people with ischemic heart disease and seizure disorders were at increased risk. Young women with seizure disorders aged 20–34 years, while not the largest group, had a risk of drowning 23 times greater than the general population.

The most common activities leading to drowning were aquatic activities such as swimming (25%) and boating (24%) and most often occurred in lakes or ponds (36%), and most deaths (63% to 84%) occurred when the person was alone or not witnessed. The majority (81%) of people who drowned were male, and about two-thirds (63%) drowned in urban areas.

Of note were the number of drownings in bathtubs in people with seizure (53%) or neurocognitive disorders (28%).

Drowning in bathtubs is common among those with seizure disorders, as well as most other pre-existing medical conditions. This may be an important first target for public health messaging as it is relevant to other medical conditions, and safety planning is easier to implement than in other locations."

Dr. Cody Dunne, emergency resident physician, University of Calgary and coauthors

The authors emphasize that people with seizure disorders should use a shower instead of tub bathing and, if possible, do so when another person is home.

As swimming is good for overall health and quality of life, people with ischemic heart disease who are at higher risk of drowning should not avoid swimming. Rather, the authors recommend a safe, informed approach to water activities.

"People with cardiovascular disease should speak with a health care provider before water activity, gradually increase intensity, wear a life jacket and participate in a supervised setting or with a trained buddy," they write.

Prevention strategies tailored to specific groups and ages, including guidance for safely performing daily activities such as bathing, will help manage the risk of drowning.