Title of article:

Weight loss increases and fat loss decreaess all-cause mortality rate: results from two independent cohort studies

Authors: Allison DB, Zannolli R, Faith MS, Heo M, Pietrobelli A, Vanitallie TB, Pi-Sunyer FX, Heymsfield SB.
Presented at: ACSM 46th Annual meeting, 1999.

Abstract

Objective: In epidemiologic studies, weight loss (WL) is usually associated with increased mortality rate. Contrarily, among obese people, WL reduces other risk factors for disease and death. We hypothesized that this paradox could exist because weight is used as an implicit adiposity index. No study has considered the independent effects of WL and fat loss (FL) on mortality rate. We studied mortality rate as a function of WL and FL.
Design: Analysis of time to death in two prospective population-based cohort studies, the Tecumseh Community Health Study (1,890 subjects, 321 deaths within 16 years of follow-up) and the Framingham Heart study ( 2,731 subjects; 507 deaths within 8 years of follow-up), in which weight and fat (via skinfolds) loss were assessable.
Results: In both studies, regardless of the statistical approach, WL was associated with increased and FL with decreased mortality rate (p<0.05). Each standard deviation (SD) of WL (4.6 kg in Tecumseh, 6.7 kg in Framingham) was estimated to increase the hazard rate 29% (95% CI, 14%, 47%) and 39% (95% ci, 25%, 54%), in the two samples respectively. Contrarily, each SD of FL (10.0 mm in Tecumseh, 4.8 mm in Framingham) was estimated to reduce the hazard rate 15% (95% CI, 4%, 25%) and 17% (95% CI, 8%,25%) in Tecumseh and Framingham respectively. Generalizability of these results to severely (i.e. BMI>=34) obese individuals is unclear.
Conclusions: Among individuals that are not severely obese, WL is associated with increased mortality rate and FL with decreased mortality rate.

Comments and Key points

The point seems to be: Weight loss is associated with increased mortality rate, but Fat loss is associated with decreased mortality rate. But this only applies to people that are not severely obese.

In severely obese people, weight loss also reduces mortality rate.

 

References

  1. http://www.tanita.com/professional/abstracts/abstract_main.html

Review & comments by Steven B. Halls, MD, Last edited 26-May-2008 Copyright.

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