10/15/2013 07:22 EDT | Updated 01/23/2014 06:58 EST

Taser, other stun gun deaths 'extremely rare'

The use of stun guns can potentially cause fatal respiratory and cardiac complications in some people, but those health effects are "extremely rare,"  a new Canadian report indicates.

However, better evidence is needed to understand the relationship between Tasers and other conductive energy weapons and adverse health affects, according to a report from the Council of Canadian Academies, in collaboration with the Canadian Academy of Health Sciences.  

The report looked at the medical and physiological impacts of such weapons.

- Facts about stun guns and their use in Canada

- Some tested Tasers fire stronger current than company says: CBC/Radio-Canada probe

- Amnesty urges moratorium on Taser use after CBC/Radio-Canada probe

"Available studies suggest that while fatal complications are biologically plausible, they would be extremely rare," the report says.

However, the report noted the absence of high-quality evidence makes it difficult to determine the health risks linked to stun guns.

A small number of cases have revealed a “temporal relationship” between stun guns and fatal cardiac arrhythmias (irregular heartbeat), but there isn’t enough evidence to confirm or exclude a causal link, the report said.

But if there is such a link, the likelihood of someone suffering a cardiac death from being the target of stun gun is low, the report added.

Health factors may contribute to death

It also looked into the relationship between sudden in-custody deaths and stun guns.

The study found that while the “electrical characteristics” of stun guns could potentially contribute to such deaths, there wasn’t enough evidence to confirm or exclude the weapons as a cause.

Drugs or alcohol, pre-existing health conditions and stress are among some of the factors that can potentially contribute to death, making it "difficult to isolate the contribution of any single factor."

The likelihood that a stun gun would be the sole cause of a sudden in-custody death is low, and what role it may play is unclear and dependent on other factors, the report said.

There are approximately 9,174 conducted energy weapons or stun guns in use in Canada. Since the late 1990s, at least 33 people have died following their use.

The Council of Canadian Academies is an independent, non-profit organization that works to provide information for public policy development. The Canadian Academy of Health Sciences is an independent assessor of science and technology issues relating to health.