TY - JOUR T1 - Obesity, waist size and prevalence of current asthma in the California Teachers Study cohort JF - Thorax JO - Thorax SP - 889 LP - 893 DO - 10.1136/thx.2009.114579 VL - 64 IS - 10 AU - J Von Behren AU - M Lipsett AU - P L Horn-Ross AU - R J Delfino AU - F Gilliland AU - R McConnell AU - L Bernstein AU - C A Clarke AU - P Reynolds Y1 - 2009/10/01 UR - http://thorax.bmj.com/content/64/10/889.abstract N2 - Background: 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. A study was undertaken to examine the relationship between the prevalence of asthma and measures of abdominal obesity and adult weight gain in addition to body mass index (BMI) in a large cohort of female teachers.Methods: Prevalence odds ratios (ORs) for current asthma were calculated using multivariable linear modelling, adjusting for age, smoking and race/ethnicity.Results: Of the 88 304 women in the analyses, 13% (n = 11 500) were obese (BMI ⩾30 kg/m2) at baseline; 1334 were extremely obese (BMI ⩾40 kg/m2). Compared with those of normal weight, the adjusted OR for adult-onset asthma increased from 1.40 (95% confidence interval (CI) 1.31 to 1.49) for overweight women to 3.30 (95% CI 2.85 to 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 to 1.59). Among obese women the OR for asthma was greater in those who were also abdominally obese than in 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 hospital admissions.Conclusions: 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. ER -