RE: BMI and mortality in the aged
Thu, 26 Aug 1999 13:04 +0000

I find this subject fascinating. Just one question: how do I measure m2? Is that the surface area of my skin, and if so, how could I get a ballpark estimate without, like, putting duct tape all over myself, cutting it off and measuring its area?

----Original Message-----

>From: Doug Skrecky <>
>Subject: BMI and mortality in the aged
>Date: Wednesday, August 25, 1999 8:02 PM
>Chubby old people seem to do well in the longevity sweapstakes.
>This seems to fit in with other research which associates risk factors
>such as low cardioresipratory fitness, and high blood pressure as being
>responsible for higher mortality in young people at either end of the BMI
>scale. These would tend to die early, yielding mostly survivors that are
>relatively healthy regardless of BMI.
> The "U" or "J" relation found in most studies relating human mortality
>with body weight, thus tends to naturally flatten out at progressively
>older ages.
> ---------- Forwarded message ----------
> Allison DB. Gallagher D. Heo M. Pi-Sunyer FX. Heymsfield SB.
> Obesity Research Center, St. Luke's/Roosevelt Hospital Center, Columbia
> University College of Physicians & Surgeons, NY 10025, USA.
> Body mass index and
> all-cause mortality among people age 70 and over: the
> Longitudinal Study of Aging.
> International Journal of Obesity & Related Metabolic Disorders.
> 21(6):424-31, 1997 Jun.
> OBJECTIVES: To assess the relationship between body
> mass index (BMI; kg/m2) and
> mortality in a large nationally representative sample of US
> adults over age 70 years. DESIGN: Prospective longitudinal cohort study, the
> Longitudinal Study of Aging (LSOA). Subjects were all those 7260 black and
> white people (2769 men, 4491 women) initially interviewed in 1984 for whom
> height and weight were available. These subjects were followed through to
> 1990. MEASUREMENTS: Measurements included self-reported height and weight,
> date of death if subjects died, sex, age, race, measures of socio-economic
> status, number of living first degree relatives, and responses to questions
> asking whether the subject had retired due to poor health, had difficulty
> eating, worried about their health, and felt their health was worse than
> during the prior year. Smoking status was not assessed. RESULTS: When
> analyzed via Cox proportional hazard regression, the relationship between BMI
> and mortality, represented by means of hazard ratio, was
> clearly U-shaped for both men and women. The base of the curves was fairly
> wide suggesting that a broad range of BMIs are well tolerated by older
> adults. The minimum mortality (estimated from the fitted
> proportional hazard models) occurred at a BMI of approximately 31.7 for women
> and 28.8 for men. The results were essentially unchanged, if analyses were
> weighted, if various disease states were controlled for, and if apparently
> unhealthy subjects were excluded. CONCLUSIONS: The finding of the relatively
> high BMI (27-30 for men, 30-35 for women) associated with minimum hazard in
> persons older than seventy years supports some previously documented findings
> and opposes others and, if confirmed in future research, has implications for
> public health and clinical recommendations.