a1 Laboratory Medicine and Epidemiology/Biostatistics, University of California San Francisco, San Francisco, CA, USA
a2 Blood Systems Research Institute, 270 Masonic Avenue, San Francisco, CA 94118, USA
a3 Westat Inc., Rockville, MD, USA
a4 American Red Cross Blood Services, New England Region, Farmington, CT, USA
a5 American Red Cross Blood Services, Southern Region, Atlanta, GA, USA
a6 Emory University, Atlanta, GA, USA
a7 Hoxworth Blood Center, University of Cincinnati Medical Center, Cincinnati, OH, USA
Objective According to the 2007–2008 National Health and Nutrition Examination Survey, the prevalence of obesity in the US population was 33·8 %; 34·3 % and 38·2 %, respectively, in middle-aged men and women. We asked whether available blood donor data could be used for obesity surveillance.
Design Cross-sectional study of BMI and obesity, defined as BMI ≥ 30·0 kg/m2. Adjusted odds ratios (aOR) were calculated with logistic regression.
Setting A network of six US blood centres.
Subjects Existing data on self-reported height and weight from blood donors, excluding persons deferred for very low body weight.
Results Among 1 042 817 donors between January 2007 and December 2008, the prevalence of obesity was 25·1 %; 25·7 % in men and 24·4 % in women. Obesity was associated with middle age (age 50–59 years v. <20 years: aOR = 1·92 for men and 1·81 for women), black (aOR = 1·57 for men and 2·35 for women) and Hispanic (aOR = 1·47 for men and 1·49 for women) race/ethnicity compared with white race/ethnicity, and inversely associated with higher educational attainment (college degree v. high school or lower: aOR = 0·56 for men and 0·48 for women) and double red cell donation and platelet donation.
Conclusions Obesity is common among US blood donors, although of modestly lower prevalence than in the general population, and is associated with recognized demographic factors. Blood donors with higher BMI are specifically recruited for certain blood collection procedures. Blood centres can play a public health role in obesity surveillance and interventions.
(Received March 09 2011)
(Accepted November 17 2011)
(Online publication January 10 2012)