New study shows that cardio-respiratory fitness is stronger predictor of all-cause mortality than BMI in women


DALLAS- A new study from the Cooper Institute shows that using body mass (BMI) to predict the risk of all-cause mortality in women may be misleading unless cardio-respiratory fitness levels (CRF) are taken into account. Published in the June 2002 issue of Obesity Research, this is the first study of its kind to examine the effects of BMI and CRF on all-cause mortality in women.

Lead researcher Stephen Farrell, Ph.D., co-authors LeeAnn Braun, M.S., Yiling Cheng, M.D., Ph.D., Carolyn Barlow, M.S., and Steven Blair, P.E.D., followed a group of 9,925 women an average age of 43 years who were assessed at Cooper Clinic between 1970 and 1996. CRF was measured via maximal treadmill exercise test and participants were divided into three BMI categories: normal weight, overweight and obese. BMI is calculated using the following formula: [Body weight in pounds multiplied by 703] divided by height in inches 2.

The group was followed for an average of 11.4 years. During that time, 195 deaths occurred with cancer and cardiovascular disease accounting for 83 percent of the deaths. It was found that having a moderate to high level of CRF resulted in a 43 to 52 percent reduced risk of death in all women regardless of BMI.

The results of this study show that CRF is a stronger predictor of all-cause mortality in women than BMI. " This study should lead physicians and other health professionals to spend at least as much time counseling their unfit female patients to become more physically fit as they do counseling overweight women to lose weight," stated Farrell.

The Cooper Institute is a non-profit research and education center founded in 1970 by preventive medicine pioneer Kenneth H. Cooper, M.D., M.P.H. The institute is recognized for its programs that focus on exercise physiology, behavior change, children's health, obesity, nutrition, aging, diabetes, hypertension, physical activity intervention and health promotion. Their offices are located in Dallas and Denver.
 

The Relation of Body Mass Index, Cardiorespiratory Fitness, and All-Cause Mortality in Women

Stephen W. Farrell*, LeeAnn Braun{dagger}, Carolyn E. Barlow*, Yiling J. Cheng* and Steven N. Blair*

* The Cooper Institute, Dallas, Texas and
{dagger} University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas.

Correspondence: Address correspondence to Stephen W. Farrell, The Cooper Institute, 12330 Preston Road, Dallas, TX 75230. E-mail: sfarrell@cooperinst.org

Objective: To examine the relation of body mass index (BMI), cardiorespiratory fitness (CRF), and all-cause mortality in women.

Research Methods and Procedures: A cohort of women (42.9 10.4 years) was assessed for CRF, height, and weight. Participants were divided into three BMI categories (normal, overweight, and obese) and three CRF categories (low, moderate, and high). After adjustment for age, smoking, and baseline health status, the relative risk (RR) of all-cause mortality was determined for each group. Further multivariate analyses were performed to examine the contribution of each predictor (e.g., age, BMI, CRF, smoking status, and baseline health status) on all-cause mortality while controlling for all other predictors.

Results: During follow-up (113,145 woman-years), 195 deaths from all causes occurred. Compared with normal weight (RR = 1.0), overweight (RR = 0.92) and obesity (RR = 1.58) did not significantly increase all-cause mortality risk. Compared with low CRF (RR = 1.0), moderate (RR = 0.48) and high (RR = 0.57) CRF were associated significantly with lower mortality risk (p = 0.002). In multivariate analyses, moderate (RR = 0.49) and high (RR = 0.57) CRF were strongly associated with decreased mortality relative to low CRF (p = 0.003). Compared with normal weight (RR = 1.0), overweight (RR = 0.84) and obesity (RR = 1.21) were not significantly associated with all-cause mortality.

Discussion: Low CRF in women was an important predictor of all-cause mortality. BMI, as a predictor of all-cause mortality risk in women, may be misleading unless CRF is also considered.

Obesity Research -- Abstracts: Farrell et al. 10 (6): 417

The relation of body mass index, cardiorespiratory fitness, and all-cause mortality in women.

Farrell SW, Braun L, Barlow CE, Cheng YJ, Blair SN.

The Cooper Institute, Dallas, Texas 75230, USA. sfarrell@cooperinst.org

OBJECTIVE: To examine the relation of body mass index (BMI), cardiorespiratory fitness (CRF), and all-cause mortality in women. RESEARCH METHODS AND PROCEDURES: A cohort of women (42.9 +/- 10.4 years) was assessed for CRF, height, and weight. Participants were divided into three BMI categories (normal, overweight, and obese) and three CRF categories (low, moderate, and high). After adjustment for age, smoking, and baseline health status, the relative risk (RR) of all-cause mortality was determined for each group. Further multivariate analyses were performed to examine the contribution of each predictor (e.g., age, BMI, CRF, smoking status, and baseline health status) on all-cause mortality while controlling for all other predictors. RESULTS: During follow-up (113,145 woman-years), 195 deaths from all causes occurred. Compared with normal weight (RR = 1.0), overweight (RR = 0.92) and obesity (RR = 1.58) did not significantly increase all-cause mortality risk. Compared with low CRF (RR = 1.0), moderate (RR = 0.48) and high (RR = 0.57) CRF were associated significantly with lower mortality risk (p = 0.002). In multivariate analyses, moderate (RR = 0.49) and high (RR = 0.57) CRF were strongly associated with decreased mortality relative to low CRF (p = 0.003). Compared with normal weight (RR = 1.0), overweight (RR = 0.84) and obesity (RR = 1.21) were not significantly associated with all-cause mortality. DISCUSSION: Low CRF in women was an important predictor of all-cause mortality. BMI, as a predictor of all-cause mortality risk in women, may be misleading unless CRF is also considered.

PMID: 12055316 [PubMed - indexed for MEDLINE]