From: Doug Skrecky (oberon@vcn.bc.ca)
Date: Thu Oct 08 1998 - 10:44:20 MDT
"US Weight Guidelines: Is it Also Important to Consider Cardiorespiratory
Fitness"
International Journal of Obesity 22(Sup 2.): S2-S7 1998
Authors: CD Lee, AS Jackson and SN Blair
Abstract:
Background: The health consequences of weight ranges across low to moderate
and high levels of cardiorespiratory fitness are known.
Objective: To evaluate the validity of the 1995 US weight guidelines, while
considering cardiorespiratory fitness.
Methods: We followed 21,856 men, aged 30-83 y, who had a complete
preventive medical examination, including a maximal treadmill exercise test
and body composition assessment. There were 427 deaths (144 cardiovascular
disease (CVD); 143 cancer; 140 others) during an average of 8.1 y of
follow-up. We used Cox proportional hazards regression to examine the
relations among cardiorespiratory fitness, body mass index (BMI, kg/m2),
and all-cause and CVD mortality.
Results: After adjustment for age, examination year, cigarette smoking and
alcohol intake, we observed that men with a BMI of 19.0 to <25.0 and who
were unfit had 2.3 times the risk of all-cause mortality (95% confidence
interval (95% CI), 1.59-3.17, P<0.001) compared with fit men in this BMI
group (reference category). Unfit men with a BMI of 25.0 to <27.8 also had
a greater risk of all-cause mortality than unfit and normal weight men. Fit
men of normal weight had substantially higher CVD mortality than fit men in
each BMI group.
Conclusions: Unfit men had higher all-cause and CVD mortality than fit men.
The health benefits of normal weights appear to be limited to men who have
moderate or high levels of cardiorespiratory fitness. These data suggest
that the 1995 US weight guidelines may be misleading unless
cardiorespiratory fitness is taken into account.
Additional quote from text of the report:
"In this study, we do not intend to minimize the risk of overweight, but
we do emphasize that increasing fitness may be more important than
maintaining healthy weights. It is well documented that higher levels of
physical fitness are associated with lower incidence of all-cause and CVD
mortality. It is also established that an increase in fitness improves CVD
risk factors and extends longevity. Thus we strongly recommend to public
health policy makers the importance of maintaining acceptible levels of
cardiorespiratory fitness.
Although our findings are limited to Caucasian men in middle and upper
socioeconomic levels, this is the first study that presents data on
longevity for the US weight guidelines categories, combined with
cardiorespiratory fitness levels. Our data clearly show that greater
longevity in men meeting the normal weight criterion of the 1995 US weight
guidelines is limited to men who have moderate or high levels of
cardiorespiratory fitness. These data suggest that cardiorespiratory
fitness should be considered when defining body weight standards."
(from Table 2) Multivariate Relative Risk of Death
BMI Fit Unifit
19.0 - <25.0 1.0 2.25
25.0 - <27.8 0.96 1.68
>=27.8 (obese) 1.08 2.24
Additional comment from the poster:
Which is the more important factor affecting mortality rates: fitness or
fatness? It looks like fitness is all important, and how fat you are is
irrelevant. Data from other studies shows that dieters have an elevated
mortality rate, while for those who exercise it is lower. The medical
establishment's recommendations to lose weight in whose who are judged to
be overweight is thus shown to be misguided. Sloth, not fatness kills.
As far as diet goes, a number of factors are associated with decreased
mortality rates. Increased fruit, vegetable, legume, grain fiber, fish, and
nut intake appear to reduce mortality, while greater (non-fish) meat intake
increases mortality. Research is ongoing to further clarify which fruits
and vegetables are associated with reduced morality rates. Artichokes,
garlic and tomatoes appear to be three stand-outs in this regard.
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