BURST
Obesity climbed 7.74 per cent in Canada thanks to the COVID-19 pandemic.
According to a new report released Monday in the Canadian Medical Association Journal, obesity increased at an accelerated rate after the onset of the pandemic.
Investment in research and interventions is needed, say the authors, to prevent and treat obesity in Canada. It should be an urgent priority for policymakers, they insist.
Obesity was recognized early on as a significant risk in exacerbating the severity of COVID-19, as well as the risk of death, say the authors. However, the impact of the pandemic on chronic disease, such as obesity, has received less scientific attention.
Researchers Laura N. Anderson, Rabiul Islam and Arthur Sweetman looked at a cross-section of data collected from 2009–2023 as part of the Canadian Community Health Survey. They drew on two studies, one pre-pandemic (2009-2020) and a second completed during the pandemic (2020-2023).
“The pandemic led to unprecedented and rapid changes in the daily lives of people in Canada, including adverse changes in sedentary time, physical activity, diet, food insecurity, stress, mental health, and the worsening of many socioeconomic factors, including job loss and higher costs of living,” they write in the report. “Many of these … factors have been associated with a greater risk of developing obesity.”
How have obesity numbers changed since 2009?
In 2023, 32.69 per cent of adults in Canada (10.6 million people) were overweight with a Body-Mass Index (BMI) of 30 or higher (27.5 or higher for people of Asian descent). This was an absolute increase of nearly 8 per cent from 2009, when the prevalence was 24.95 per cent.
Compared with the 11 years before the pandemic, obesity increased at a greater rate during the four years after the pandemic arrived.
Did obesity climb more in some groups of Canadians?
Specific subgroups of the population were affected more than others by increased obesity, particularly females and younger adults, the researchers concluded.
Is obesity prevalence in Canada different from elsewhere?
The overall findings of an increase in obesity during the COVID-19 pandemic are consistent with studies from several other countries and populations, according to the researchers.
What about weight-loss drugs?
GLP-1 medications (such as Ozempic, Wegovy, Contrave or Rybelsus) for treatment of diabetes and weight loss were introduced in Canada during the study period, though they were not widely available for obesity treatment. But the researchers question the impact of these medications going forward, and wonder whether they will dampen pandemic exacerbated obesity trends.
Hasn’t BMI been questioned as a measurement tool for obesity?
The authors conceded that BMI as a measurement tool has limitations. BMI is calculated as the weight in kilograms divided by the height in metres squared. It has been the standard measure for defining obesity because it is quick, inexpensive, noninvasive, and has some correlation to metabolic disease prevalence.
However, BMI categories indicating underweight, normal, overweight, obese, etc., differ for Asian Americans who have a higher risk of metabolic disease at lower BMI values. The researchers say they used different thresholds for people of Asian (South Asian, Chinese, Filipino, Southeast Asian, Korean and Japanese) descent.
Another anomaly is that some men who are deemed overweight according to BMI but don’t have excess middle-body fat can have lower overall mortality risk than men in other BMI weight categories. There is also evidence of an obesity paradox where obesity has protective effects for patients with a history of previously diagnosed heart failure.
Despite these caveats, the researchers argue that for population-level screening and surveillance, using “BMI categories as a proxy for obesity in adults continues to be recommended.”
What could future studies show?
The researchers are advocating for future studies to understand longer-term trends, specifically to evaluate whether the steep increase in obesity during the pandemic continues as a trend or falls to pre-pandemic levels.
And they wonder about the causes of upward trends among females and younger adults – whether they were driven by increased stress or adverse mental health related to occupation or caregiving during the pandemic.
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