Elsevier

Mayo Clinic Proceedings

Volume 85, Issue 2, February 2010, Pages 115-121
Mayo Clinic Proceedings

ORIGINAL ARTICLE
Obesity Paradox and Cardiorespiratory Fitness in 12,417 Male Veterans Aged 40 to 70 Years

https://doi.org/10.4065/mcp.2009.0562Get rights and content

OBJECTIVE

To evaluate the influence of cardiorespiratory fitness (fitness) on the obesity paradox in middle-aged men with known or suspected coronary artery disease.

PATIENTS AND METHODS

This study consists of 12,417 men aged 40 to 70 years (44% African American) who were referred for exercise testing at the Veterans Affairs Medical Centers in Washington, DC, or Palo Alto, CA (between January 1, 1983, and June 30, 2007). Fitness was quantified as metabolic equivalents achieved during a maximal exercise test and was categorized for analysis as low, moderate, and high (defined as <5, 5-10, and >10 metabolic equivalents, respectively). Adiposity was defined by body mass index (BMI) according to standard clinical guidelines. Separate and combined associations of fitness and adiposity with all-cause mortality were assessed by Cox proportional hazards analyses.

RESULTS

We recorded 2801 deaths during a mean ± SD follow-up of 7.7±5.3 years. Multivariate hazard ratios (95% confidence interval) for all-cause mortality, with normal weight (BMI, 18.5-24.9 kg/m2) used as the reference group, were 1.9 (1.5-2.3), 0.7 (0.7-0.8), 0.7 (0.6-0.7), and 1.0 (0.8-1.1) for BMIs of less than 18.5, 25.0 to 29.9, 30.0 to 34.9, and 35.0 or more kg/m2, respectively. Compared with highly fit normal-weight men, underweight men with low fitness had the highest (4.5 [3.1-6.6]) and highly fit overweight men the lowest (0.4 [0.3-0.6]) mortality risk of any subgroup. Overweight and obese men with moderate fitness had mortality rates similar to those of the highly fit normal-weight reference group.

CONCLUSION

Fitness altered the obesity paradox. Overweight and obese men had increased longevity only if they registered high fitness.

Section snippets

PATIENTS AND METHODS

VETS is an ongoing, prospective epidemiological investigation of veteran patients that began in 1983. All patients are referred for exercise testing either as a routine evaluation or as an evaluation for exercise-induced ischemia. Participants in the current study were drawn from a cohort of 15,660 male veterans (excluding patients with a history of implanted pacemaker, those who developed left bundle-branch block during the test, and those who were clinically unstable or required emergent

RESULTS

During a mean ± SD follow-up of 7.7±5.3 years (range, 0.08-22.92 years), 2801 deaths were recorded. Baseline characteristics grouped according to BMI category are presented in Table 1. The study population consisted of 6982 (56.2%) white and 5435 (43.8%) African American men who ranged in age from 40 to 70 years. There were 137 underweight patients (1.1%), 2885 normal-weight (23.2%), 5187 overweight (41.8%), and 4208 obese (33.9%) (2893 obese I [23.3%], 947 obese II [7.6%], and 368 obese III

DISCUSSION

In multivariate analyses, both fitness and BMI were independently and inversely associated with mortality risk. To ascertain whether low BMI resulted from undetected illness at baseline, we excluded all patients who died during the first 2 years of follow-up and current smokers, but this did not substantially change the primary findings. In joint analyses, elevated BMI generally reduced mortality risk within each fitness category, and higher levels of fitness decreased mortality risk within

CONCLUSION

Both higher BMI and higher fitness were protective for all-cause mortality in this cohort of white and African American middle-aged male veterans with known or suspected CVD. Fitness altered the obesity paradox such that overweight and obese men had increased longevity only if they registered high fitness. Future studies should focus on the influence of fitness and BMI on mortality in diverse populations and whether changes in fitness level and/or body weight affect health outcomes.

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