Department of Cardiovascular Diseases, John Ochsner Heart and Vascular Institute, Ochsner Clinic Foundation, New Orleans, LA 70121, USA.
J Cardiopulm Rehabil Prev. 2013 Mar-Apr;33(2):77-83. doi: 10.1097/HCR.0b013e31828254fc.
Despite its many shortcomings, body mass index (BMI) is the most widely used screening tool for obesity, in part, because of its practicality. Other more physiologic measurements of obesity are based on body fat (BF). However, the correlation between BMI and BF has not been well-characterized, especially in patients with coronary heart disease (CHD).
We retrospectively studied 581 patients with CHD following major CHD events, who were divided according to BMI (calculated as weight divided by height squared), based on the World Health Organization standard cutoff points (underweight [<18.5 kg/m], normal [≥18.5 and <25 kg/m], overweight [≥25 and <30 kg/m], and obese [≥30 kg/m]). Second, the population was divided according to BF, on the basis of the age- and gender-adjusted Gallagher BF classification into underweight, normal, overweight, and obese categories.
Body mass index and percent BF correlated significantly (r = 0.60; P < .0001) and classified patients in the same category in about 59% of patients. In approximately 27% of the sample, BMI underestimated BF, while in about 14% of cases BMI overestimated BF. The relationship between BMI and BF was influenced by age, gender, and BMI itself.
Even though a correlation exists between BMI and BF, they frequently classify individuals differently in a population of CHD patients. When defining overweight/obesity, care must be taken when using a crude screening tool such as BMI. While it is not expected for all clinicians to add BF assessments within routine patient assessments, the results of this study may be helpful to guide clinicians and researchers who are considering different aspects of body composition.
尽管身体质量指数（BMI）存在诸多缺陷，但它仍是最广泛使用的肥胖筛选工具，部分原因在于其实用性。肥胖的其他更生理的测量方法基于体脂（BF）。然而，BMI 与 BF 之间的相关性尚未得到很好的描述，尤其是在冠心病（CHD）患者中。
我们回顾性研究了 581 例主要 CHD 事件后发生 CHD 的患者，根据世界卫生组织标准切点（体重除以身高的平方），将患者分为 BMI（<18.5kg/m 为消瘦，≥18.5 且<25kg/m 为正常，≥25 且<30kg/m 为超重，≥30kg/m 为肥胖）。其次，根据年龄和性别调整后的 Gallagher BF 分类，将人群分为消瘦、正常、超重和肥胖。
BMI 与 BF 呈显著相关（r = 0.60；P <.0001），约 59%的患者将患者分类到相同类别。在大约 27%的样本中，BMI 低估了 BF，而在大约 14%的情况下，BMI 高估了 BF。BMI 和 BF 之间的关系受年龄、性别和 BMI 本身的影响。
尽管 BMI 与 BF 之间存在相关性，但它们在 CHD 患者人群中经常将个体分类不同。在使用 BMI 等粗略的筛选工具定义超重/肥胖时，必须谨慎。虽然预计并非所有临床医生都要在常规患者评估中添加 BF 评估，但本研究的结果可能有助于指导正在考虑身体成分不同方面的临床医生和研究人员。
