1. Bigger Waist Means Higher Asthma Risk Summary and Comment by Wendy S. Biggs, MD Published in Journal Watch Women's Health September 24, 2009Journal Watch Women's Health Women with waist measurements >88 cm had higher risk for asthma than women in the same BMI categories but with smaller waist measurements. CopyrightCopyright © 2009. Massachusetts Medical Society. All rights reserved.Massachusetts Medical Society

2. Covering Von Behren J et al. Obesity, waist size and prevalence of current asthma in the California Teachers Study cohort. Thorax 2009 Aug 25; [e-pub ahead of print]. (http://dx.doi.org/10.1136/thx.2009.114579) CopyrightCopyright © 2009. Massachusetts Medical Society. All rights reserved.Massachusetts Medical Society

3. Background Obesity is a risk factor for adult-onset asthma, but the contribution of excess abdominal fat to this relation is unclear. Investigators for the California Teachers Study administered questionnaires to a cohort of 133,480 female school teachers and administrators. Information was obtained about current asthma-related symptoms as well as height and weight at age 18 and at study entry. Participants measured and self-reported their waist circumference. CopyrightCopyright © 2009. Massachusetts Medical Society. All rights reserved.Massachusetts Medical Society

4. The Research Of 88,300 eligible participants, 13% were obese (BMI >30.0 kg/m2). Prevalence of asthma was 7.6% overall, 11% in obese class I women (BMI, 30.0–34.9), 13% in obese class II women (BMI, 35.0– 39.9), and 18% in extremely obese women (BMI >40.0). Overweight women (BMI, 25.0–29.9) had 40% higher risk for asthma than normal-weight women (BMI, 18.0–24.9), whereas extremely obese women had more than threefold higher risk (odds ratio, 3.3). Analysis adjusted for smoking status, age, race, and ethnicity showed that women who reported waist measurements >88.0 cm (35.2 inches) compared with those who had waist circumferences ≤88.0 cm had higher risk for asthma regardless of whether they were normal weight (OR, 1.4), overweight (OR, 1.7), or obese (OR, 2.4). CopyrightCopyright © 2009. Massachusetts Medical Society. All rights reserved.Massachusetts Medical Society

5. Comment These authors did not control for potential confounders such as other comorbid conditions, family histories of asthma, or environmental exposure to allergens. Nonetheless, their findings show that excess weight alone is not a key determinant of asthma risk; where fat is deposited is also crucial. Visceral fat differs metabolically from other body fat stores in its association with inflammatory and prothrombotic states (e.g., insulin resistance, cardiovascular disease). Thus, although higher BMI generally was associated with excess risk for asthma — an inflammatory condition of the airways — women who had large waist measurements were at even greater risk. With 66% of the U.S. population now overweight or obese, these results suggest a reason for the rising prevalence of asthma: the expanding American waistline. CopyrightCopyright © 2009. Massachusetts Medical Society. All rights reserved.Massachusetts Medical Society

6. About Journal Watch Journal Watch helps physicians and allied heath professionals save time and stay informed by providing brief, clearly written, clinically focused perspectives on the medical developments that affect practice. Journal Watch is an independent, trustworthy source, from the publishers of the New England Journal of Medicine. These slides were derived from Journal Watch Women's Health.Journal Watch Women's Health The best way to stay informed with Journal Watch, is through our alerts. To sign up, visit the My Alerts page.My Alerts page CopyrightCopyright © 2009. Massachusetts Medical Society. All rights reserved.Massachusetts Medical Society