Excess weight is protective in the elderly? New research says no

Obesity is a known health risk. The number of epidemiological studies that have linked excess weight to cardiovascular disease, cancer, diabetes, other chronic conditions, and increased risk of death is staggering.1,2 In fact, the cutoff points for BMI into overweight and obese were created to reflect increased risk of disease and death due to excess fat.3

Photo of obese man

Then there is the “obesity paradox.” This is the term used to describe the opposite of the usual finding - there are certain groups of people, usually those with severe chronic diseases such as heart failure and kidney disease, in which a higher BMI seems to be associated with a decreased mortality risk.4,5

Elderly persons are another group in which an obesity paradox has been observed in some studies.6 However, this observation is not consistent – other studies have reported an increased risk with higher BMI in adults over age 70 or 75, similar to younger age groups, and others have shown no association at all.7-11 Overall, the relationship between BMI and mortality in the elderly has been unclear.

Several explanations have been proposed to explain the paradox – these are a few examples:

  • BMI is not a true indicator of body fat – older persons tend to have more body fat at the same BMI as younger adults.3 One study found that greater waist circumference in the elderly was associated with increased mortality risk, but greater BMI was associated with decreased risk. In these individuals, greater BMI may reflect greater fat-free mass, rather than greater body fat. Waist circumference and fat-free mass may be more important indicators than BMI for obesity-associated health risks in the elderly.12,13
  • Unintentional weight loss may be involved – many older persons in these studies who are at a low or normal BMI may be there because of disease-related weight loss. Weight loss in elderly has been shown to be associated with negative health outcomes, presumably for this reason.14 So a study of elderly persons that only takes one weight measurement and does not measure weight change over time is inherently flawed.
  • Another issue with the length of studies is that weight gain late in life is probably less dangerous than weight gained earlier in life and then maintained for many years – being obese for 50 years results in more cumulative damage than being obese for 15 years. The earlier you become obese, the greater the risk of death.15,16 Therefore, long-term data (decades, not years) is needed to get an accurate picture of health risks in the elderly due to obesity.

New research has attempted to reconcile the contradictions in previous studies by using long-term data. Although the researchers used BMI rather than waist circumference, they used two weight measurements 17 years apart, and followed subjects for a total of 29 years – importantly, they only included subjects who maintained a similar weight over the first 17 years – this helped to remove any potential effects from late life weight gain or disease-related weight loss.

Men (age 75-99) who maintained a BMI greater than 22.3 had a shorter life expectancy by 3.7 years, and an 88% increased risk of death during the study period compared to men with a lower BMI. Men who maintained a BMI greater than 27.3 had double the risk of death compared to those with a BMI less than 22.3. Women in the same age group who maintained a BMI greater than 27.4 shortened their life expectancy by 2.1 years, and had a 41% increase in risk of death compared to women with a lower BMI.17,18

This new study leads us to conclude: no matter what your age, carrying excess weight for a significant length of time is dangerous – in fact, it can be deadly.

 

References: 

1. Guh DP, Zhang W, Bansback N, et al: The incidence of co-morbidities related to obesity and overweight: a systematic review and meta-analysis. BMC public health 2009;9:88.
2. McGee DL: Body mass index and mortality: a meta-analysis based on person-level data from twenty-six observational studies. Ann Epidemiol 2005;15:87-97.
3. U.S. Centers for Disease Control and Prevention: About BMI for Adults. http://www.cdc.gov/healthyweight/assessing/bmi/adult_bmi/index.html. Accessed
4. Oreopoulos A, Padwal R, Kalantar-Zadeh K, et al: Body mass index and mortality in heart failure: a meta-analysis. Am Heart J 2008;156:13-22.
5. Schmidt D, Salahudeen A: The obesity-survival paradox in hemodialysis patients: why do overweight hemodialysis patients live longer? Nutr Clin Pract 2007;22:11-15.
6. Oreopoulos A, Kalantar-Zadeh K, Sharma AM, et al: The obesity paradox in the elderly: potential mechanisms and clinical implications. Clin Geriatr Med 2009;25:643-659, viii.
7. Calle EE, Thun MJ, Petrelli JM, et al: Body-mass index and mortality in a prospective cohort of U.S. adults. N Engl J Med 1999;341:1097-1105.
8. Janssen I, Mark AE: Elevated body mass index and mortality risk in the elderly. Obes Rev 2007;8:41-59.
9. Grabowski DC, Ellis JE: High body mass index does not predict mortality in older people: analysis of the Longitudinal Study of Aging. J Am Geriatr Soc 2001;49:968-979.
10. Kuk JL, Ardern CI: Influence of age on the association between various measures of obesity and all-cause mortality. J Am Geriatr Soc 2009;57:2077-2084.
11. Stevens J, Cai J, Pamuk ER, et al: The effect of age on the association between body-mass index and mortality. N Engl J Med 1998;338:1-7.
12. Janssen I, Katzmarzyk PT, Ross R: Body mass index is inversely related to mortality in older people after adjustment for waist circumference. J Am Geriatr Soc 2005;53:2112-2118.
13. Zamboni M, Mazzali G, Zoico E, et al: Health consequences of obesity in the elderly: a review of four unresolved questions. Int J Obes (Lond) 2005;29:1011-1029.
14. Woo J, Ho SC, Sham A: Longitudinal changes in body mass index and body composition over 3 years and relationship to health outcomes in Hong Kong Chinese age 70 and older. J Am Geriatr Soc 2001;49:737-746.
15. Adams KF, Schatzkin A, Harris TB, et al: Overweight, obesity, and mortality in a large prospective cohort of persons 50 to 71 years old. N Engl J Med 2006;355:763-778.
16. Sun Q, Townsend MK, Okereke OI, et al: Adiposity and weight change in mid-life in relation to healthy survival after age 70 in women: prospective cohort study. BMJ 2009;339:b3796.
17. Singh PN, Haddad E, Tonstad S, et al: Does excess body fat maintained after the seventh decade decrease life expectancy? J Am Geriatr Soc 2011;59:1003-1011.
18. Contrary to Earlier Findings, Excess Body Fat in Elderly Decreases Life Expectancy. 2011. ScienceDaily. http://www.sciencedaily.com/releases/2011/08/110811151325.htm. Accessed September 29, 2011.

 

Being just overweight, not obese, still shortens lifespan

It is becoming more widely known that obesity can lead to a premature death – but what about those who fall in between healthy weight and obese?  A new study suggests that even “a few extra pounds” can be dangerous.

This comes just a few months after a large study that concluded that waist circumference was associated with risk of death from all causes. These two studies used different methods of measurement, but they agree on a very important point – even a small amount of excess weight increases the risk of death. In the waist circumference study, even people who had a normal body mass index (BMI; calculated based on height and weight) were at greater risk of death if they had a 4-inch larger waist compared to others in their BMI category – that four extra inches of abdominal fat translated into a 16% (men) and 25% (women) increase in mortality risk over a nine year period.

Last week, another article was published in the New England Journal of Medicine in which the researchers analyzed risk of death from all causes according to BMI. The data they analyzed came from 19 different studies and included 1.46 million people across the U.S., Europe and Australia. The results were dramatic. The risk of death from all causes was elevated just above the ‘normal’ BMI category and continued to climb as BMI increased. Those who were overweight but not obese were still at risk.

Compared to individuals with BMI of 20-24.9, the increased risk of death was

  • 13% for those with BMI 25.0-29.9
  • 44% for those with BMI 30.0-34.9
  • 88% for those with BMI 35.0-39.9
  • 251% for those with BMI 40.0-49.9[1]

Of course, the risk is greater with more excess weight, but the key finding is that even with a moderate amount of excess weight, there is a significant increase in the risk of death.

Sixty-eight percent of Americans are overweight or obese, and about half of this group fall into the overweight but not obese category. These studies would therefore suggest that 68% of Americans are dying prematurely because of their excess weight. The prevalence of processed foods and junk food has gotten most Americans completely out of touch with hunger and satiety signals. Nutrient-dense eating, resulting in the recognition of true hunger, is an effective method for reaching and maintaining a healthy weight.

 

Reference:
1. Berrington de Gonzalez, A., et al., Body-mass index and mortality among 1.46 million white adults. N Engl J Med, 2010. 363(23): p. 2211-9.

 

Study Compares Veggie Diets vs. Low-Carb --UPDATE--

Editor’s Note: This is a guest post from Steven Acocella, MS, DC, DACBN and does NOT necessarily represent the opinions of DiseaseProof or Dr. Fuhrman.

At the Beltsville Human Nutrition Research Center in Maryland and published in the Journal of the American Dietetic Association researchers evaluated the short to medium term weight loss results of popular diets. Popular diets: correlation to health, nutrition, and obesity grouped the most popular diets into categories based upon the prescribed ratios of energy for each macronutrient. If you remember from Nutrition 101, caloric energy comes from only 3 sources, fat, carbohydrate and protein. For example, diets such as The South Beach Diet and The Atkins Diet derive 50% or more calories from fat while Dr. Fuhrman’s Eat to Live derives the majority of energy from natural, unrefined carbohydrate.

The study looked at food intake over a 2 year period and included several hundred participants who followed the various diet styles compliantly. They then analyzed the relationship between a reduction of Body Mass Index (BMI), the diet style and the Healthy Eating Index (HEI).

The Healthy Eating Index scores were highest for the vegetarian or near vegetarian diet style and lowest for the low carbohydrate, high fat diets. Conversely, energy intake was highest for the Low Carbohydrate group, often exceeding the average accepted recommendations of 2000 Kcal/day or men and 1500 Kcal/day for women. This is strange considering these were weight loss eating plans that were followed intently.

The weight loss results were no surprise. The healthiest body mass was seen in the vegetarian group. A direct, proportional relationship was seen with a rise in the percentage of calories derived from fat and BMI. As the percentage of fat calories increased so did those subject’s BMI. Total calories were also directly related to the percentage of dietary fat with the average daily energy intake for the vegetarian or nearly vegetarian group consuming 1450 Kcal/day and the high fat diet group consuming 2200 Kcal/day. Researchers noted the relationship between the Healthy Eating Index verses calorie and fat percentages were inversely related.

Putting all this together, this important study using an excellent group of subjects has made the following observations: diets low in fat have the highest Healthy Eating Index scores and are generally the lowest in total calories. Those subjects on these diets enjoyed the most favorable BMI measurements and other biomarkers of health. Conversely, the high fat, low carbohydrate diet styles have the lowest Healthy Eating Index scores and those that consumed this diet style had poor BMI measurements and other indicators of health.

It is worth mentioning that the authors of this study discuss a review of the literature suggests that weight loss is independent of dietary composition and is solely a result of total calories consumed. They suggest that their findings, although supportive of this confers that successful, healthy weight loss over time is a function of quality as well as quantity.

UPDATE: Dr. Fuhrman had some thoughts on Steven’s post:

My health equation, Health = Nutrition / Calories is almost entirely ignored by the scientific community. If the micronutrient density index of a particular diet was published along with the other characteristics researchers would place less emphasis on the relative macronutrient composition and more on the micronutrient composition. Nevertheless, the long-term health potential of a given diet is based so much more on its micronutrient profile rather than its macronutrient profile.

Image credit: altopower

Greener Kids are Slimmer Kids

A new study in the American Journal of Preventive Medicine reveals city kids living in greener neighborhoods were thinner. Researchers found a relationship between “greenness” and slower increase in body mass index over time; HealthDay News reports.

Putting kids to bed helps too. Oh, and keep them away from cockroaches!