Waist circumference can significantly predict asthma, even for people who aren't technically overweight, according to a study in Thorax. Of the more than 88,000 female schoolteachers in California surveyed, 7.5% reported having asthma. Of those, women with waist circumferences of 35.2 inches or larger but body mass indexes below 25 -- the official cutoff for 'overweight' -- were over one-third more likely than other 'normal' weight women to have asthma. （Women with large waists who were also obese were even more likely to have asthma.） The findings suggest that abdominal fat may contribute to asthma independently of overall body fat, the researchers said. While the specific pathways aren't crystal clear, excess fat tissue in the abdomen is thought to increase the risk for asthma by restricting and inflaming airways.

Caveat: Because it used a one-time survey, originally intended to track breast cancer, the study's researchers were unable to follow patients as their diagnoses changed over time, and thus couldn't conclude that obesity or abdominal fat definitively led to asthma.

根据《胸腔》（Thorax）杂志上的一项研究，腰围可以有效预测哮喘，甚至是对那些理论上并不超重的人。对加利福尼亚88,000多名女教师的调查发现，7.5%的人患有哮喘。其中，腰围为35.2英寸或更粗，但体重指数低于25（"超重"的公认分界线）的女性患哮喘的概率比其他"正常"体重的女性高出三分之一强。（腰粗而肥胖的女性患哮喘的概率更高。）研究人员称，这一发现表明，腹部脂肪对哮喘的影响可能独立于全身脂肪的影响。尽管具体作用方式尚不完全明了，但研究人员认为，腹部的多余脂肪组织限制了气道并使其发炎，从而增加了罹患哮喘的风险。

注意：由于这项研究使用的是一次性调查，最初目的是追踪乳腺癌，因此研究人员无法在病人的诊断结果随时间的推移发生变化时对其进行跟踪，因此不能得出肥胖或腹部肥胖必定导致哮喘的结论。