RT Journal Article SR Electronic T1 Obesity, Waist Size, and Prevalence of Current Asthma in the California Teachers Study Cohort JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society DO 10.1136/thx.2009.114579 A1 Julie Von Behren A1 Michael Lipsett A1 Pamela L. Horn-Ross A1 Ralph J Delfino A1 Frank Gillilan A1 Rob McConnell A1 Leslie Bernstein A1 Christina A Clarke A1 Peggy Reynolds YR 2009 UL http://thorax.bmj.com/content/early/2009/08/25/thx.2009.114579.abstract AB Obesity is a risk factor for asthma, particularly in women, but few cohort studies have evaluated abdominal obesity, which reflects metabolic differences in visceral fat known to influence systemic inflammation. We examined the relationships of asthma prevalence with measures of abdominal obesity and adult weight gain, in addition to body mass index (BMI), in a large cohort of female teachers. We calculated prevalence odds ratios (ORs) for current asthma using multivariable linear modeling, adjusting for age, smoking, and race/ethnicity. Of the 88,304 women in the analyses, 13% (11,500) were obese (BMI ≥ 30 kg/m2) at baseline; 1,334 were extremely obese (BMI ≥ 40). Compared to those of normal weight, the adjusted OR for adult-onset asthma increased from 1.40 (95% confidence interval (CI): 1.31, 1.49) for overweight women to 3.30 (95% CI: 2.85, 3.82) for extremely obese women. Large waist circumference (> 88 cm) was associated with increased asthma prevalence even among women with a normal BMI (OR = 1.37, 95% CI: 1.18, 1.59). Among obese women, the OR for asthma was greater among those who were also abdominally obese compared to women whose waist was ≤88 cm (2.36 vs. 1.57). Obese and overweight women were at greater risk of severe asthma episodes, measured by urgent medical visits and hospitalizations. This study confirms the association between excess weight and asthma severity and prevalence, and showed that a large waist was associated with increased asthma prevalence even among women considered to have normal body weight.