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Obesity and Psychological Distress: The Risk of Disability
In Session With Norbert Schmitz, PhD:
Obesity and Psychological Distress: The Risk of Disability
Associate Professor of Psychiatry; Associate Member, Department of Epidemiology, Biostatistics & Occupational Health, McGill University, Montréal, Quebec
First published in Psychiatry Weekly, Volume 7, Issue
3, on February 6, 2012
Q: How can co-occurring obesity and psychological distress affect health outcomes and functioning?
A: Our previous research on chronic conditions suggests that there is a synergistic relationship between obesity with a high level of psychological distress or depression and poor functioning and disability. In the present study, we examined data from a large prospective study, the Canadian National Population Health Survey, with over 18,000 participants, and 14 years of follow-up data, to assess the risk of developing disability as a result of obesity, psychological distress, or both.
Body Mass Index (BMI) and levels of psychological distress, measured by Kessler 6 (K6), were collected for obese and non-obese people at baseline, in 1994. To distinguish short-term incidental distress from chronic psychological distress, people with medium to high distress scores both at baseline and 2-year follow-up were categorized as having psychological distress. Disability was gauged by the Health Utility index, an 8-domain self-report outcome measure that focuses on functioning related to, but not limited to, the ability to see, speak, hear, or walk; mobility; cognition and memory; emotional health; and pain status.
In subjects with both obesity and distress at baseline, there was a much higher risk of disability than expected.
We compared 4 groups of people: (1) no obesity and no distress, (2) obesity and no distress, (3) distress but no obesity, and (4) both obesity and distress. The no obesity and no distress group was our reference group. We looked at the incidence of disability for people who had no disability at baseline but developed disability later. As expected, we found that obesity is a risk factor for disability (hazard ratio, 1.7), which is well known and well established. Psychological distress without obesity was also a risk factor for disability (hazard ratio, 1.8). But when we looked at those with both obesity and distress at baseline, there was a much higher risk of disability than expected (hazard ratio, 3.4), which would suggest that there is a synergistic effect of some interaction between co-occurring obesity and distress to create a much higher chance of developing disability.
Q: How might psychological distress affect the risk of developing disability?
A: The psychosocial aspect here is very important. Those with psychological distress very often have poorer lifetime behavior, more smoking and alcohol consumption to deal with stress, and less physical activity. If some or all of these behaviors coincide with obesity, which is already an independent risk factor for chronic conditions and disability, it may have an additional effect of poorer risk outcomes. It would therefore be important to focus on psychological distress in people with obesity.
Disclosure: This work was supported by a grant from the Canadian Institutes of Health Research (MOP-9924), awarded to Dr. Schmitz.
References:
1. Gariepy G, Wang J, Lesage A, Schmitz N. Obesity and the risk of disability in a 12-year cohort study: the role of psychological distress. Soc Psychiatry Psychiatr Epidemiol. 2011;46:1173–1179.