Statistics Canada says the COVID-19 pandemic contributed to an average seven-month decline in national life expectancy, the largest decrease recorded since 1921 when the vital statistics registration system was introduced.

The federal agency released preliminary data Monday showing national life expectancy, which is estimated on an annual basis, was 81.7 years for those born in 2020 - down from 82.3 the year before.

The drop was greater for men, at more than eight months, than for women, at nearly five months, and the largest declines in the country were observed in Quebec, Ontario, Manitoba, Saskatchewan, Alberta and British Columbia.

There were 307,205 deaths in Canada in 2020, representing a 7.7 per cent increase from 2019. Of those, 16,151 deaths were attributed to COVID-19 during the first year of the pandemic, representing 5.3 per cent of the country's 2020 deaths.

That made COVID-19 the third leading cause of death in Canada in 2020, though Statistics Canada added that the pandemic may have also contributed indirectly to a number of other deaths across the country.

Cancer was the leading cause of death at 26.4 per cent while heart disease was second at 17.5 per cent.

Statistics Canada found that mortality rates for cancer, heart disease and COVID-19 were higher in lower-income neighbourhoods.

Unintentional injuries were the fourth leading cause of death at five per cent, with stroke, chronic lower respiratory diseases, diabetes mellitus, influenza and pneumonia, Alzheimer's disease and chronic liver disease and cirrhosis rounding out the top 10.

Though Canada's life expectancy fell in 2020, it was still among the highest in the world over that year, Statistics Canada said.

Some countries, including Spain, Italy and the United States saw greater impact on life expectancy from the pandemic, with declines up to 1.5 years. Others, including Norway, Denmark and Finland, saw life expectancy remain stable or even increase in 2020, despite the pandemic.

Statistics Canada said life expectancy for those born in 2020 is expected to return to pre-pandemic levels as the impacts of the health crisis diminish.

The data released Monday is preliminary, Statistics Canada said, and does not include information on deaths in Yukon.

The rate of influenza and pneumonia deaths in 2020 was 12.9 deaths per 100,000 population, a decline from the 15.6 deaths per 100,000 seen in 2019. That marked the lowest death rate attributed to flu and pneumonia in more than 20 years.

People aged 65 years and older accounted for 94.1 per cent of all COVID-19 deaths in Canada in 2020, with more than half - 54.6 per cent - occurring in people older than 84.

Canadians younger than age 40 were largely unaffected by the direct effects of the pandemic, Statistics Canada said, with approximately 50 COVID-19 deaths recorded among that age group in 2020. But the agency added that in younger age groups, increases in deaths attributed to other causes, including substance-related harms, were observed.

Canada recorded 4,604 deaths due to accidental poisonings, including overdoses. That figure was up from 3,705 deaths reported in 2019 but comparable to the 4,501 deaths reported in 2018 and the 4,830 deaths reported in 2017 at the height of the pre-pandemic opioids crisis.

Statistics Canada also said there were “notable increases” in alcohol-induced deaths in 2020, particularly in those younger than 65. In people under 45, alcohol-induced deaths rose to 542 in 2020, from around 360 in each of 2017, 2018 and 2019.

The agency said alcohol-induced deaths include fatalities from diseases and conditions related to chronic use of alcohol but exclude unintentional deaths such as traffic accidents where alcohol is believed to be a contributing factor.

This report by The Canadian Press was first published Jan. 24, 2022.