Abstract
Archived Content
Information identified as archived is provided for reference, research or recordkeeping purposes. It is not subject to the Government of Canada Web Standards and has not been altered or updated since it was archived. Please "contact us" to request a format other than those available.
Background
The cumulative toll of exposure to stressors (psychosocial, chemical, physical) can contribute to disease processes. The concept of allostatic load, essentially the cost of maintaining physiological stability in response to environmental demands, may be useful in assessing broad population health impacts of stressors beyond morbidity and mortality. In the present study, allostatic load scores were generated for Canadians and associations with age, sex, education and household income were examined.
Methods
Data from cycles 1, 2, and 3 (2007 to 2013) of the Canadian Health Measures Survey (CHMS) were used to generate a composite index of cumulative health burden (allostatic load score) for adults aged 20 to 79 (n=8,678) based on risk thresholds for nine biological measures: diastolic blood pressure, systolic blood pressure, heart rate, high-density lipoprotein (HDL), total cholesterol, glycated hemoglobin (HBA1c), waist-to-hip ratio, C-reactive protein (CRP), and albumin. Logistic regression models that included age (continuous), sex, education and household income were fit to generate model-adjusted predicted allostatic load scores.
Results
The most prevalent individual risk factors were elevated waist-to-hip ratio, elevated CRP, total cholesterol, and low HDL. Allostatic load scores increased with age. Males generally exhibited higher scores than females. Lower educational attainment and lower household income were found to be significantly associated with higher allostatic load scores after taking account of the effects of age and sex.
Interpretation
Age and socioeconomic gradients are associated with differences in allostatic load scores in the Canadian population. This composite measure of multisystem dysfunction, generated from a nationally representative survey that includes measurement of numerous health-relevant behaviours, biomarkers, and chemical levels, can be used in future to quantify sub-clinical impacts on health.
Keywords
allostatic load, Canadian Health Measures Survey, stress, age, sex, socioeconomic position
DOI: https://www.doi.org/10.25318/82-003-x201900600002-eng
Findings
Chronic diseases are the leading cause of death and the greatest burden on health care systems in Canada and around the world. In addition to age and heredity, determinants of morbidity and mortality include behavioural factors (e.g., diet, tobacco use, physical activity levels) and environmental stressors (e.g., neighbourhood socioeconomic deprivation, exposure to pollutants, noise). Gradients in health associated with individual and societal factors have prompted investigation of underlying mechanisms to inform risk assessment and management initiatives. Estimating cumulative or combined impacts of stressors is a significant challenge for risk assessment; there are multiple pathways to morbidity and mortality, and resulting health impacts may depend on the nature, timing, magnitude, and duration of exposures as well as individual susceptibility factors. A key knowledge gap hampering assessment of cumulative and combined effects of stressors (broadly defined and encompassing psychosocial, physical, and chemical) is the lack of metric or metrics to characterize risk due to interactions of multiple stressors in the human population. Moreover, inter-individual differences in stress response and resilience present a further complication, as these are rarely captured in epidemiological studies and may modify the effects of a given stressor. [Full article]
Authors
Errol M. Thomson (errol.thomson@canada.ca) is with the Hazard Identification Division, and Harun Kalayci and Mike Walker are with the Population Studies Division of the Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario.
Start of text box
What is already known on this subject?
- Allostatic load, or the wear and tear of responding to cumulative stressors, is a measure of chronic physiological stress and a predictor of future health problems.
- While allostatic load scores have been assessed in national studies elsewhere, there have been no comparable studies in Canada to date.
What does this study add?
- Using data from the Canadian Health Measures Survey (2007 to 2013), allostatic load scores were generated for a nationally representative population of Canadian adults.
- Allostatic load scores were higher for males than females, increased with age, and were highest in those with lower educational attainment and household income.
- This measure of physiological dysfunction can be used in future to quantify subclinical health impacts of exposure to a variety of stressors and behaviours.
End of text box
- Date modified: