Original Research Communications Cardiorespiratory fitness body composition and all cause and cardiovascular disease mortality in men1 3 Chong Do Lee Steven N Blair and Andrew S Jackson ABSTRACT Background Cardiorespiratory fitness and body fatness are both related to health but their interrelation to all cause and cardiovascular disease CVD mortality is unknown Objective We examined the health benefits of leanness and the hazards of obesity while simultaneously considering cardiorespiratory fitness Design This was an observational cohort study We followed 21 925 men aged 30 83 y who had a body composition assessment and a maximal treadmill exercise test There were 428 deaths 144 from CVD 143 from cancer and 141 from other causes in an average of 8 y of follow up 176 742 man years Results After adjustment for age examination year cigarette smoking alcohol intake and parental history of ischemic heart disease unfit low cardiorespiratory fitness as determined by maximal exercise testing lean men had double the risk of all cause mortality of fit lean men relative risk 2 07 95 CI 1 16 3 69 P 0 01 Unfit lean men also had a higher risk of all cause and CVD mortality than did men who were fit and obese We observed similar results for fat and fat free mass in relation to mortality Unfit men had a higher risk of all cause and CVD mortality than did fit men in all fat and fat free mass categories Similarly unfit men with low waist girths 87 cm had greater risk of all cause mortality than did fit men with high waist girths 99 cm Conclusions The health benefits of leanness are limited to fit men and being fit may reduce the hazards of obesity Am J Clin Nutr 1999 69 373 80 KEY WORDS Body composition cardiorespiratory fitness epidemiology mortality cardiovascular disease mortality all cause mortality fat mass fat free mass waist girth men INTRODUCTION Obesity is a public health problem in the United States 1 and the prevalence of obesity has increased substantially over the past few decades 2 However the health effects of body fatness in relation to longevity are unclear Many studies show increased mortality in the leanest as well as the most obese individuals 3 6 but others do not observe this trend 7 9 Manson et al 9 suggest that findings of high mortality rates in individuals with low weight forheight are associated with methodologic limitations such as failure to control for cigarette smoking failure to eliminate early mortal ity due to preexisting disease and inappropriate control for obesity related biological factors Nonetheless a recent meta analysis documented elevated mortality in association with leanness after accounting for smoking and preexisting disease 10 Another unexplored methodologic limitation in obesity research is that body mass index BMI in kg m2 is commonly used to examine the obesity mortality association even though BMI is not an accurate measure of obesity Rather it mainly indicates overweight for height but does not discriminate between fat mass and fat free mass FFM Some studies show higher death rates in individuals with low BMIs and high waist to hip circumference ratios WHRs but not in those with high BMIs and low WHRs 11 13 The health effects of overweight on height and body composition in relation to cardiovascular disease CVD risk factors need further research 14 15 There has been little research on the relation between measured body fatness and mortality 16 We believe that cardiorespiratory fitness should also be considered in examining the relation between body composition and mortality Cardiorespiratory fitness is a powerful predictor of all cause and CVD mortality 17 19 and appeared to attenuate the relation between BMI and mortality in an earlier study 20 However the health effects of body fatness and cardiorespiratory fitness in relation to longevity remain unexplored Therefore the purpose of this study was to examine the health consequences of body fatness and cardiorespiratory fitness in relation to all cause and CVD mortality in men We also assessed the associations of fat mass FFM and waist circumference to mortality after taking cardiorespiratory fitness into account SUBJECTS AND METHODS Subjects and measurements Subjects were 21 925 men aged 30 83 y who had complete preventive medical evaluations between 1971 and 1989 at the 1 From the Division of Epidemiology Clinical Applications Cooper Institute for Aerobics Research Dallas and the Department of Health and Human Performance University of Houston 2 Supported in part by US Public Health Service research grant AG06945 from the National Institute on Aging Bethesda MD and Polar Electro Oy Kempele Finland 3 Address reprint requests to SN Blair 12330 Preston Road Dallas TX 75230 E mail sblair cooperinst org Received February 11 1998 Accepted for publication August 4 1998 Am J Clin Nutr 1999 69 373 80 Printed in USA 1999 American Society for Clinical Nutrition 373 374 LEE ET AL Cooper Clinic in Dallas All subjects were residents of the United States and had no personal history of myocardial infarction stroke or cancer at baseline All received body composition assessments and reached 85 of their age predicted maximal heart rate 220 age in y during their treadmill tests The study protocol was reviewed and approved annually by the Institutional Review Board All subjects gave their informed written consent for the medical evaluation and subsequent registration in the follow up study The medical evaluation performed after subjects had fasted overnight for 12 h included a physical examination anthropometric measurements electrocardiogram blood chemistry analyses blood pressure assessment maximal exercise treadmill test self report of health habits and recording of demographic characteristics Additional details of examination procedures are published elsewhere 17 19 Serum samples were analyzed by automated techniques in a laboratory that participates in the Centers for Disease Control and Prevention Lipid Standardization Program and blood pressure was measured by auscultatory methods with a mercury sphygmomanometer Body weight and stature were measured with a standard physician s scale and stadiometer In a subgroup of 14 043 men waist circumference was measured at the level of the umbilicus with a plastic tape measure Body composition was assessed either by hydrostatic weighing by skinfold thickness measurements or both following a standard procedure 21 We determined percentage body fat in men by