Ortega Francisco B, Sui Xuemei, Lavie Carl J, Blair Steven N
PROFITH "PROmoting FITness and Health through physical activity" Research Group, Department of Physical Education and Sports, Faculty of Sport Sciences, University of Granada, Granada, Spain; Department of Biosciences and Nutrition at NOVUM, Karolinska Institutet, Huddinge, Sweden.
Department of Exercise Science, University of South Carolina, Columbia.
Mayo Clin Proc. 2016 Apr;91(4):443-55. doi: 10.1016/j.mayocp.2016.01.008. Epub 2016 Mar 2.
To examine whether an accurate measure (using a criterion standard method) of total body fat would be a better predictor of cardiovascular disease (CVD) mortality than body mass index (BMI).
A total of 60,335 participants were examined between January 1, 1979, and December 31, 2003, and then followed-up for a mean follow-up period of 15.2 years. Body mass index was estimated using standard procedures. Body composition indices (ie, body fat percentage [BF%], fat mass index [FMI], fat-free mass [FFM], and FFM index [FFMI]) were derived from either skinfold thicknesses or hydrostatic weighing. For exact comparisons, the indices studied were categorized identically using sex-specific percentiles.
Compared with a medium BMI, a very high BMI was associated with a hazard ratio (HR) of 2.7 (95% CI, 2.1-3.3) for CVD mortality, which was a stronger association than for BF% or FMI (ie, HR, 1.6; 95% CI, 1.3-1.9 and HR, 2.2; 95% CI, 1.8-2.7, respectively). Compared with a medium FFMI, a very high FFMI was associated with an HR of 2.2 (95% CI, 1.7-2.7) for CVD mortality, with these estimates being markedly smaller for FFM (ie, HR, 1.2; 95% CI, 0.9-1.6). When the analyses were restricted only to the sample assessed with hydrostatic weighing (N=29,959, 51.7%), the results were similar, with even slightly larger differences in favor of BMI (ie, HR, 3.0; 95% CI, 2.2-4.0) compared with BF% and FMI (ie, HR, 1.5; 95% CI, 1.2-1.9 and HR, 2.1; 95% CI, 1.6-2.7, respectively). We estimated Harrell's c-index as an indicator of discriminating/predictive ability of these models and observed that the c-index for models including BMI was significantly higher than that for models including BF% or FMI (P<.005 for all).
The simple and inexpensive measure of BMI can be as clinically important as, or even more than, total adiposity measures assessed using accurate, complex, and expensive methods. Physiological explanations for these findings are discussed.
研究采用标准方法精确测量的全身脂肪是否比体重指数（BMI）更能预测心血管疾病（CVD）死亡率。
1979年1月1日至2003年12月31日期间共检查了60335名参与者，随后进行了平均15.2年的随访。采用标准程序估算BMI。身体成分指数（即体脂百分比[BF%]、脂肪量指数[FMI]、去脂体重[FFM]和去脂体重指数[FFMI]）通过皮褶厚度测量或水下称重法得出。为了进行精确比较，所研究的指数根据特定性别的百分位数进行相同分类。
与中等BMI相比，极高BMI与CVD死亡率的风险比（HR）为2.7（95%置信区间[CI]，2.1 - 3.3），这一关联比BF%或FMI更强（即HR分别为1.6；95%CI，1.3 - 1.9和HR为2.2；95%CI，1.8 - 2.7）。与中等FFMI相比，极高FFMI与CVD死亡率的HR为2.2（95%CI，1.7 - 2.7），对于FFM而言这些估计值明显更小（即HR为1.2；95%CI，0.9 - 1.6）。当分析仅局限于通过水下称重评估的样本（N = 29959，51.7%）时，结果相似，与BF%和FMI相比，支持BMI的差异甚至稍大（即HR为3.0；95%CI，2.2 - 4.0）（即HR分别为1.5；95%CI，1.2 - 1.9和HR为2.1；95%CI，1.6 - 2.7）。我们将Harrell氏c指数作为这些模型区分/预测能力的指标进行估算，观察到包含BMI的模型的c指数显著高于包含BF%或FMI的模型（所有P <.005）。
简单且成本低廉的BMI测量在临床上可能与使用精确、复杂且昂贵方法评估的总体肥胖测量同样重要，甚至更重要。文中讨论了这些发现的生理学解释。
