It may be timely to review the body mass index (BMI) classification for older adults as new research suggests that older overweight people are less likely to die over a 10 year period than their normal weight peers.

A statistical measurement which utilises a person's height and weight, the BMI has long been used as a formula by the World Health Organization to enable health professionals to discuss weight problems objectively with their patients.

However, a decade-long research project led by Winthrop Professor Leon Flicker at The University of Western Australia found that the category of overweight based on the index may not be a useful tool for Australian men and women aged between 70 and 75.

Professor Flicker and his team assessed 9,200 men and women for their health and lifestyle as part of a study into healthy ageing.  They found that adults aged over 70 years who are classified as overweight are less likely to die than adults in the normal weight range.  The researchers also found that this holds true for the common causes of death including both cancer and cardiovascular disease; and that being sedentary doubles the risk of death for women but only increases the risk by a quarter in men.

Published in the Journal of the American Geriatrics Society, the study sheds light on the situation in Australia, ranked the third most obese country after the United States and the United Kingdom.

These results add evidence to the claims that the WHO's BMI thresholds for overweight and obese are overly restrictive for older people.  However, the benefits were only seen in the overweight category and not in those people who are obese.  This research found that the same was true for men and women. 

"The study shows that those people who survive to age 70 in reasonable health (and hence participate in these studies) have a different set of risks and benefits associated with the amount of body fat compared with younger people," Professor Flicker said.

"Concerns had been raised about encouraging overweight older people to lose weight and the object of our study was to examine the major unresolved question of ‘what level of BMI is associated with the lowest mortality risk in this group?'"

This study is published in the February issue of the Journal of the American Geriatrics Society.  Media wishing to receive a PDF of this article may contact medicalnews@wiley.com

Full citation:  Flicker L, McCaul KA, Hankey GJ, Jamrozik K., Brown WJ, Byles JE, Almeida OP; Body Mass Index and Survival in Older Men and Women Aged 70 to 75 Years; The Journal of the American Geriatrics Society (2009); DOI: 0.1111/j.1532-5415.2009.02677.x

About the Author:  Leon Flicker, MB BS, PhD, FRACP, is based at the Western Australian Centre for Health and Ageing, Centre for Medical Research, Western Australian Institute for Medical Research, The University of Western Australia.  He is a Professor of Geriatric Medicine at UWA, a Consultant Geriatrician at Royal Perth Hospital and Director of the Western Australian Centre for Health and Ageing.

About the Journal:  The Journal of the American Geriatrics Society is a comprehensive and reliable source of monthly research and information about common diseases and disorders of older adults.  The journal is published by Wiley-Blackwell on behalf of the American Geriatrics Society.  For more information, please visit www.blackwellpublishing.com/jgs. 

Media references

Professor Leon Flicker  (+61 8) 9224 3992
Janine MacDonald (UWA Public Affairs)  (+61 8)  6488 5563  /  (+61 4) 32 637 716