Smoking, Obesity and both in US

Smoking, obesity, and their co-occurrence in the United States: cross sectional analysis -- Healton et al. 333 (7557): 25 -- BMJ: "Conclusions Although the proportion of adults who smoke and are obese is relatively low, this subgroup is concentrated among lower socioeconomic groups.
Introduction
Obesity and cigarette smoking are primary risk factors for several chronic conditions and early death in a large number of people in the United States. The prevalence of smoking among adults is 22.5% (45.8 million people).1 The proportion of obese adults is also high�about 31% of adults have a body mass index of 30 or more.2 Although smoking and obesity are public health priorities in the US,3 the overlap between the two conditions has not been measured at population level. Because the presence of these two conditions together probably carries an increased risk to health, statistics on how these conditions overlap could help in the development of an effective policy for prevention and treatment.
Methods
We used data from the 2002 national health interview survey (NHIS) to conduct a cross sectional analysis of 29 305 adults ( 18 years) and estimate the proportion of adults in the US who smoke and are obese. Prevalence was stratified by various sociodemographic factors. Rubin's multiple imputation procedure was used to replace missing values of family income. We analysed all data with Stata software, version 8 and adjusted the results with sampling weights to derive population estimates from the survey sample.
Results
Nearly 41.5% of adults (81 million aged 18 years) in the US are obese or smoke, and about 4.7% (9 million) smoke and are obese (table). Overall, 5.3% of men and 4.2% of women smoke and are obese. This proportion is higher in African Americans (7.0%) than in other racial or ethnic groups. A gr/.../"