Sunday, June 1, 2008

Obesity and Weight Loss Surgery in Older Age

Older age has been defined differently in different studies, as either 60 or 65 years of age.

The average body weight and BMI gradually increase during most of adult life and reach peak values at age 50–59. After the age of 60 years, the average population body weight and BMI tend to decrease. Notice that those who die prematurely because of obesity will be removed from the count of older population, and hence the lower average BMI. There is evidence that, in reality, body weight and BMI do not change, or decrease only slightly, in older people. In persons who are more than 80 years of age, obesity is about one-half that observed in the age group of 50–59. As you may see, this is another evidence that the chances that a morbidly obese patient survive through the age 80 are markedly diminished.

How about weight loss in older age? Well, we have to be very careful reading the data, because it is very easy to jump into the wrong conclusions. Several studies evaluated the relationship between weight loss and mortality in older age. Population data from all studies found that losing weight or experiencing weight variability in older age was correlated with higher mortality compared with those whose weight did not change on the average. But read carefully, because the studies did not show if the weight changes were intentional or unintentional. Older patients may lose weight, without intending to, because of serious health problems, terminal disease, or dementia. So, it is no wonder if weight loss on the average is associated with higher mortality, if the population includes those who did not intend to lose weight. Indeed, a study from the Royal Free and University College Medical School, London, England, concluded that intentional weight loss was associated with a significant reduction in mortality in markedly overweight men. The data also suggested that the earlier the intervention, the greater the chance of benefit. So, older patients can benefit from the health advantages of losing some extra weight. Another statistical twist for the mathematically inclined, is that obese patients who survive through older years represent already a pre-selected subgroup that has already defeated the fatal effects of obesity, and their survival represents selection bias, skewing the statistics in favor of better health for higher BMIs. However, it is hard to predict if an individual obese person will be one of those who will defeat the obesity, or will suffer the consequences.

There are changes that are likely to develop with age, like loss of muscle mass and loss of bone (osteopenia and osteoporosis). Whether weight loss is intentional or unintentional, there is a higher risk of bone loss (osteopenia and osteoporosis) and bone fractures, including hip fractures. Therefore, it cannot be emphasized enough that older patients (and, of course younger patients, too) who seek bariatric surgery should adhere to the dietary instructions, supplements and maintain a high level of activity, including exercise. They also should check their bone density, vitamin D and parathyroid hormone levels periodically.

Stay Healthy!


Villareal DT, Apovian CM, Kushner RF, Klein S; American Society for Nutrition; NAASO, The Obesity Society. Obesity in older adults: technical review and position statement of the American Society for Nutrition and NAASO, The Obesity Society. Am J Clin Nutr. 2005 Nov;82(5):923-34. Review. [PMID: 16280421] (Full Text)

Wannamethee SG, Shaper AG, Lennon L.Reasons for intentional weight loss, unintentional weight loss, and mortality in older men. Arch Intern Med. 2005 May 9;165(9):1035-40.[ PMID: 15883243] (Abstract)

French SA, Folsom AR, Jeffery RW, Williamson DF.P rospective study of intentionality of weight loss and mortality in older women: the Iowa Women's Health Study. Am J Epidemiol. 1999 Mar 15;149(6):504-14. [PMID: 10084239] (Abstract)