Abstract
Background: An understanding of the risk factors contributing to disease burden is critical for determining research priorities and informing national health policy. We aimed to identify the risk factor trends in Canada. Methods: As part of the Global Burden of Disease (GBD) study (1990-2016), we conducted an analysis of country-level estimates for Canada to assess the burden of diseases and injuries attributable to risk factors. For both 1990 and 2016, metabolic, environmental and behavioural risk factors were ranked according to their contribution to disability-adjusted life years (healthy years of life lost), total deaths and years lived with disability. Results: In 2016, the risk factors accounting for the largest percentage of disability-adjusted life years in Canada were (1) tobacco, (2) diet, (3) high body mass index, (4) high fasting plasma glucose, (5) high systolic blood pressure, (6) alcohol and drug use, (7) occupational risks, (8) high total cholesterol, (9) impaired kidney function and (10) air pollution. Risk factor rankings remained similar from 1990 to 2016 despite some substantial declines in burden, including a 47% (± 3%) decline in the age-standardized disability-adjusted life years rate attributable to tobacco since 1990. Risk factors with an increasing contribution to disability-adjusted life years rates from 1990 to 2016 included high body mass index, high fasting plasma glucose and alcohol and drug use. Interpretation: Metabolic and behavioural risk factors, including modifiable factors such as tobacco use and diet, remain the leading risk factors contributing to the burden of diseases and injuries in Canada. This work identifies priorities and targets for reducing premature death and disability burden in Canada.
Generated Summary
This research, part of the Global Burden of Disease (GBD) Study, analyzes country-level estimates for Canada from 1990 to 2016 to assess the burden of diseases and injuries attributable to various risk factors. The study ranks metabolic, environmental, and behavioral risk factors based on their contribution to disability-adjusted life years (DALYs), total deaths, and years lived with disability. The GBD study employs a comparative risk assessment approach to quantify the influence of risk factors on disease burden, using data from various sources, including randomized controlled trials, cohort studies, and census data. The methodology, which is reviewed and updated annually, adheres to the Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER). The study’s aim is to inform national health policy and programs by identifying the leading risk factors contributing to health loss in Canada and evaluating their trends over time. The primary goal is to offer insights into risk factors to reduce the burden of premature death and disability in Canada. The analysis includes an examination of trends from 1990 to 2016 for DALYs, deaths, and years lived with disability, focusing on the drivers of the observed trends in risk-attributable DALYs. The study also provides a comprehensive Canadian analysis of both disability and premature death on the same scale in relation to risk factors.
Key Findings & Statistics
- In 2016, the leading risk factors accounting for the largest percentage of disability-adjusted life years (DALYs) in Canada were: (1) tobacco, (2) diet, (3) high body mass index, (4) high fasting plasma glucose, (5) high systolic blood pressure, (6) alcohol and drug use, (7) occupational risks, (8) high total cholesterol, (9) impaired kidney function, and (10) air pollution.
- The study estimated that in 2016, 39.6% (36.9% to 42.3%) of DALYs, 56.0% (53.6% to 58.2%) of deaths, and 24.2% (22.7% to 25.8%) of years lived with disability in Canada could be attributed to the assessed risk factors.
- In 2016, the 10 leading risk factors contributing to all-cause DALYs in Canada (reported as % of total DALYs [95% UI]) were: tobacco (10.6% [9.4 to 11.9]), dietary risks (9.4% [7.7% to 11.2%]), high body mass index (BMI) (9.0% [6.2% to 11.8%]), high fasting plasma glucose (7.3% [5.8% to 9.2%]), high systolic blood pressure (7.1% [6.0% to 8.2%]), alcohol and drug use (6.9% [5.8% to 8.1%]), occupational risks (4.8% [4.4% to 5.3%]), high total cholesterol (3.7% [2.9% to 4.6%]), impaired kidney function (2.1% [1.9% to 2.3%]), and air pollution (1.3% [1.0% to 1.7%]).
- In terms of total deaths in 2016, the 5 leading all-cause, all-age attributable risk factors (reported as % of total deaths [95% UI]) were: dietary risks (17.6% [14.7% to 20.5%]), tobacco (17.5% [16.6% to 18.5%]), high systolic blood pressure (14.7% [12.3% to 17.2%]), high fasting plasma glucose (11.2% [7.9% to 15.3%]), and high BMI (10.8% [6.9% to 15.0%]).
- High BMI was the top risk factor contributing to years lived with disability in Canada (7.3% [5.1% to 9.4%]), followed by high fasting plasma glucose (5.5% [4.8% to 6.3%]) and alcohol and drug use (5.4% [4.5% to 6.5%]).
- Since 1990, exposure to tobacco has continued to be the leading risk factor for all-cause DALYs even though declines in the tobacco-attributable all-age DALY rate (-25.7% [-30.1% to -21.1%]) and the tobacco-attributable age-standardized DALY rate (-47.4% [-50.5% to -44.1%]) were observed over the last 27 years.
- High BMI and high fasting plasma glucose have both increased in ranking to become the third and fourth leading risk factors.
- Alcohol and drug use attributable all-age and age-standardized DALY rates have increased by 13.3% (0.0% to 30.4%) and 8.5% (-5.4% to 26.4%) since 1990.
- The all-age attributable DALY rate has decreased for high systolic blood pressure (-34.4% [-38.6% to -30.0%]) and high cholesterol (44.5% [-48.8% to -39.8%]) since 1990, leading to improvements in their respective rankings.
- Among the leading risk factors contributing to all-cause total deaths, the risk factor contributing to a substantial increase in the death rate from 1990 to 2016 was high BMI, which increased by 22.3% (4.2% to 54.8%).
- Alcohol and drug use ranked ninth as an attributable risk for deaths, but its contribution to the all-age and age-standardized death rates has risen by 66.4% (13.6% to 251.1%) and 36.4% (-7.8% to 202.2%), respectively, since 1990.
- The risk factors contributing to all-cause years lived with disability have changed from 1990, with high BMI and high fasting plasma glucose becoming the top 2 risk factors, reflecting a 61.0% (46.0% to 85.8%) and 40.2% (26.5% to 55.3%) increase in the all-age attributable years lived with disability rates associated with these risk factors.
Other Important Findings
- The leading risk factors for DALYs were similar for men and women, except for alcohol and drug use (ranked higher for men) and high systolic blood pressure (ranked higher for women).
- The leading risk factors for disability were high BMI and high fasting plasma glucose (through endocrine and musculoskeletal disorders).
- The leading risk factors for mortality were diet and tobacco (through cancer and cardiovascular disease).
- Decomposition analysis showed that communicable and noncommunicable diseases attributable to risk factor exposure are declining in Canada.
- Injuries resulting from risk factor exposure are increasing in Canada.
Limitations Noted in the Document
- The present analysis used Canadian data from numerous sources across the country; however, important sources of data may not yet be included in the GBD study.
- With current GBD Canada estimates, the study is unable to explain why risk factors rose or fell in their rankings or to stratify by province/territory.
- The study could not incorporate data on the social determinants of health (e.g., housing, income, ethnicity, education) that strongly influence risk factors.
- There may also be other risk factors that are important but not included in the GBD, including psychosocial factors such as social isolation.
- Estimates of the GBD study have not been validated against a similar study because no initiative of the same scope exists for comparison.
Conclusion
The study identifies that in Canada, modifiable metabolic and behavioral risk factors, such as tobacco use and diet, continue to be the leading contributors to the burden of diseases and injuries. This aligns with the observation that these risk factors have remained relatively unchanged since 1990, despite substantial declines in burden related to diet and tobacco. High systolic blood pressure and high total cholesterol have decreased in ranking but remain significant. The contribution of alcohol and drug use, high BMI, and high fasting plasma glucose to the burden of diseases and injuries increased from 1990 to 2016. Despite the declines, the study highlights that tobacco exposure remains a major risk factor, particularly among older Canadians. The trends observed in Canada are similar to those reported in analyses of US and UK GBD data, with tobacco and diet as the primary risk factors. The long latency period associated with tobacco-related diseases and the complex interplay of factors influencing dietary risks underscore the need for long-term, comprehensive strategies. The study underscores the importance of sustained efforts to reduce risk factors, as these can influence the population for a substantial duration. Future research should focus on specific risk factors for a more detailed understanding of their complexities and to continuously inform the reduction of health burden.