HEALTH NEWS

Study Title:

Weight History and Mortality Risk

Study Abstract

We sought to determine whether the Edmonton Obesity Staging System (EOSS), a newly proposed tool using obesity-related comorbidities, can help identify obese individuals who are at greater mortality risk. Data from the Aerobics Center Longitudinal Study (n = 29 533) were used to assess mortality risk in obese individuals by EOSS stage (follow-up (SD), 16.2 (7.5) years). The effect of weight history and lifestyle factors on EOSS classification was explored. Obese participants were categorized, using a modified EOSS definition, as stages 0 to 3, based on the severity of their risk profile and conditions (stage 0, no risk factors or comorbidities; stage 1, mild conditions; and stages 2 and 3, moderate to severe conditions). Compared with normal-weight individuals, obese individuals in stage 2 or 3 had a greater risk of all-cause mortality (stage 2 hazards ratio (HR) (95% CI), 1.6 (1.3-2.0), stage 3 HR, 1.7 (1.4-2.0)) and cardiovascular-related mortality (stage 2 HR, 2.1 (1.6-2.8), stage 3 HR. 2.1 (1.6-2.8)). Stage 0/1 was not associated with higher mortality risk. Lower self-ascribed preferred weight, weight at age 21, cardiorespiratory fitness, reported dieting, and fruit and vegetable intake were each associated with an elevated risk for stage 2 or 3. Thus, EOSS offers clinicians a useful approach to identify obese individuals at elevated risk of mortality who may benefit from more attention to weight management. Further research is necessary to determine what EOSS factors are most predictive of mortality risk, and whether these findings can be generalized to other obese populations.

From press release:

Fat and Healthy? Study Finds Slim Isn't Always Superior

ScienceDaily (Aug. 17, 2011) — A study out of York University has some refreshing news: Being fat can actually be good for you.

Published in the journal Applied Physiology, Nutrition and Metabolism, the study finds that obese people who are otherwise healthy live just as long as their slim counterparts, and are less likely to die of cardiovascular causes.

"Our findings challenge the idea that all obese individuals need to lose weight," says lead author Jennifer Kuk, assistant professor in York's School of Kinesiology & Health Science, Faculty of Health. "Moreover, it's possible that trying -- and failing -- to lose weight may be more detrimental than simply staying at an elevated body weight and engaging in a healthy lifestyle that includes physical activity and a balanced diet with plenty of fruits and vegetables," she says.

Kuk's team looked at 6,000 obese Americans over a 16-year span, comparing their mortality risk with that of lean individuals.

They found that obese individuals who had no (or only mild) physical, psychological or physiological impairments had a higher body weight in early adulthood, were happier with this higher body weight, and had attempted to lose weight less frequently during their lives. However, these individuals were also more likely to be physically active and consume a healthy diet.

Researchers used a newly-developed grading tool, the Edmonton Obesity Staging System (EOSS), which has been found to be more accurate than body mass index (BMI) for identifying who should attempt to lose weight. Developed by University of Alberta researchers, it is modelled on staging systems that classify the extent and severity of other diseases such as cancer, mental illness and heart disease. It offers five stages of obesity based on both traditional physical measurements such as BMI and waist-to-hip ratio, plus clinical measurements that reflect medical conditions often caused or aggravated by obesity (such as diabetes, hypertension and heart disease).

Kuk stresses that in order to determine whether or not they should lose weight, individuals should see a physician to be evaluated using the EOSS criteria.

Study Information

Jennifer L. Kuk, Chris I. Ardern, Timothy S. Church, Arya M. Sharma, Raj Padwal, Xuemei Sui, Steven N. Blair.
Edmonton Obesity Staging System: Association with weight history and mortality risk.
Appl Physiol Nutr Metab.
2011 August
School of Kinesiology and Health Science, York University, Toronto, ON M3J 1P3, Canada.