Current issues of ACP Journal Club are published in Annals of Internal Medicine


Etiology

High ratio of waist circumference to hip circumference increased the risk for death in older women

ACP J Club. 1993 July-Aug;119:28. doi:10.7326/ACPJC-1993-119-1-028


Source Citation

Folsom AR, Kaye SA, Sellers TA, et al. Body fat distribution and 5-year risk of death in older women. JAMA. 1993 Jan 27;269:483-7.


Abstract

Objective

To determine if body mass index (BMI) and the ratio of waist circumference to hip circumference (WHR) are risk factors for 5-year mortality in older women.

Design

5-year cohort study of participants in the Iowa Women's Health Study.

Setting

General population in Iowa.

Participants

41 837 respondents (98% white) of 98 030 randomly selected women between 55 to 69 years of age who had a valid Iowa driver's license in 1985. 660 women (2%) were excluded because of missing baseline data.

Assessment of risk factors

Baseline height and weight in 1986 and weight at 1 year before baseline and at the ages of 18, 30, 40, and 50 years were reported on the baseline questionnaire. Waist and hip circumferences were also measured and reported. Information on educational level, marital status, smoking status and amount, alcohol intake, hormone replacement therapy status, reproductive history, and prevalent diseases was also collected.

Main outcome measures

All-cause and cause-specific mortality assessed through linkage with state and national death indexes.

Main results

1504 deaths occurred during the 5-year follow-up period, 52% from cancer and 32% from cardiovascular disease. Age-adjusted mortality rates were elevated in the leanest as well as in the most obese women, for both never smokers and ever smokers, giving a J-shaped association for BMI and mortality. Risk for death was positively associated with WHR, increasing monotonically across each quintile of WHR. Women in the fifth quintile had a > 2-fold increased risk for death compared with women in the first quintile. After adjustment for age, BMI, smoking, education, marital status, estrogen and alcohol use, a 0.15-unit increase in WHR was associated with a 1.60-fold increase (95% CI 1.47 to 1.74) in the relative risk for death. The women at most risk for death were those with a low BMI and a high WHR. The associations observed were altered only slightly when weight loss before baseline and higher early deaths among lean women were considered.

Conclusions

Among older Iowa women, the association between body mass index and all-cause mortality was J-shaped, but the ratio of waist circumference to hip circumference was positively and monotonically associated with total mortality.

Sources of funding: National Cancer Institute; Centers for Disease Control and Prevention; National Institutes of Health.

For article reprint: Dr. A.R. Folsom, Division of Epidemiology, School of Public Health, University of Minnesota, 1300 South 2nd Street, Suite 300, Minneapolis, MN 55454-1105, USA. FAX 612-624-0315.


Commentary

Folsom and colleagues have gone beyond previous studies of obesity as a risk factor for several chronic diseases and death. The important outcome of this study for primary care practice is the finding that abdominal adiposity measured by WHR is a stronger predictor than BMI for overall mortality in women aged 55 to 69 years.

The study methods were generally sound, although the response rate of < 50% is of some concern. The results included age-adjusted relative risks and multivariate analyses. Validation of study methods are referenced and the authors present a balanced discussion of potential confounding variables.

As we begin to emphasize gender and age differences through the lifespan, especially important in the care of an aging population wishing to retain vitality and health, it is necessary to modify screening and practice guideline recommendations that are to be implemented by primary care physicians (1). A controlled, randomized, preventive intervention study among primary care patients, 65 to 89 years of age residing in a retirement community, documented the utility of informing patients of physiologic, clinical laboratory, and body fat distribution measurements to assist with health behavioral changes (2).

Folsom and colleagues make a compelling case for inclusion of the WHR, in addition to the traditional height and weight measures, in every primary care practice. Additional studies are required to further support the conclusion of this study. Other ethnic and socioeconomic populations must also be studied to allow generalizability to a more diverse population of women.

Robert M. Schmidt, MD, MPH, PhD
California Pacific Medical CenterSan Francisco, California, USA


References

1. Fisher M, ed. Guide to Clinical Preventive Services. An Assessment of the Effectiveness of 169 Interventions. Report of the U.S. Preventive Services Task Force. Baltimore: Williams & Wilkins; 1989.

2. Schmidt RM, Wu M, Stewart AL, et al. Evaluating outcomes of healthy aging interventions: the Health Watch of Arizona Study in the sun cities. Gerontologist. 1990;30:34A-6A.