Moore S C, Mayne S T, Graubard B I, Schatzkin A, Albanes D, Schairer C, Hoover R N, Leitzmann M F
Nutritional Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Department of Health and Human Services, Bethesda, MD 20892, USA.
Int J Obes (Lond). 2008 May;32(5):730-9. doi: 10.1038/sj.ijo.0803801. Epub 2008 Jan 22.
Epidemiologic studies of body mass index (BMI) in relation to mortality commonly exclude persons with health conditions and/or a history of smoking to prevent bias resulting from illness-related weight loss ('reverse causation'). Analysis of BMI from an earlier time period may minimize reverse causation without requiring exclusion of participants based on disease or smoking history.
We prospectively examined BMI based on technician measurements of weight and height from 10 years prior to start of follow-up in relation to subsequent mortality in a cohort of 50 186 women who were 40-93 years old at baseline in 1987-1989. Deaths were ascertained through the US National Death Index. Proportional hazards regression was used to estimate hazard ratios (HRs) of mortality, adjusted for age, education, race/ethnicity, income, menopausal hormone use, smoking and physical activity.
During 10 years of follow-up through 1997, 5201 women died. Overall, we observed a J-shaped association between BMI and mortality, with increased risk for women who were underweight, overweight or obese. The HRs and 95% confidence intervals of mortality for BMI categories of <18.5, 18.5-20.9, 21.0-23.4 (reference), 23.5-24.9, 25.0-27.4, 27.5-29.9, 30.0-34.9 and 35.0+ kg m(-2) were 1.43 (1.19, 1.72), 1.07 (0.98, 1.17), 1.00 (reference), 1.10 (1.00, 1.20), 1.20 (1.11, 1.31), 1.23 (1.11, 1.37), 1.60 (1.44, 1.77) and 1.92 (1.64, 2.24). There was little evidence that pre-existing conditions (heart disease, diabetes and/or cancer) or smoking history modified the past BMI and mortality relation (P=0.54 and 0.76).
In this large cohort of women, BMI based on technician measurements of weight and height from 10 years prior to baseline showed increased risk for mortality across the range of overweight and obesity, regardless of disease and smoking history. Observed associations between overweight, obesity and mortality in healthy individuals may also apply to persons with a history of disease or smoking.
关于体重指数（BMI）与死亡率关系的流行病学研究通常会排除患有健康问题和/或有吸烟史的人群，以防止因疾病相关体重减轻（“反向因果关系”）导致的偏差。分析较早时间段的BMI可能会将反向因果关系降至最低，而无需根据疾病或吸烟史排除参与者。
我们前瞻性地研究了在1987 - 1989年基线时年龄为40 - 93岁的50186名女性队列中，随访开始前10年由技术人员测量的体重和身高得出的BMI与随后死亡率之间的关系。通过美国国家死亡指数确定死亡情况。使用比例风险回归来估计死亡率的风险比（HRs），并对年龄、教育程度、种族/民族、收入、绝经后激素使用、吸烟和身体活动进行了调整。
在截至1997年的10年随访期间，5201名女性死亡。总体而言，我们观察到BMI与死亡率之间呈J形关联，体重过轻、超重或肥胖的女性风险增加。BMI类别<18.5、18.5 - 20.9、21.0 - 23.4（参考）、23.5 - 24.9、25.0 - 27.4、27.5 - 29.9、30.0 - 34.9和35.0+ kg m(-2)的死亡率HRs及95%置信区间分别为1.43（1.19，1.72）、1.07（0.98，1.17）、1.00（参考）、1.10（1.00，1.20）、1.20（1.11，1.31）、1.23（1.11，1.37）、1.60（1.44，1.7）和1.92（1.64，2.24）。几乎没有证据表明既往疾病（心脏病、糖尿病和/或癌症）或吸烟史会改变过去BMI与死亡率之间的关系（P = 0.54和0.76）。
在这个大型女性队列中，基于基线前10年技术人员测量的体重和身高得出的BMI显示，无论疾病和吸烟史如何，超重和肥胖范围内的死亡率风险都会增加。在健康个体中观察到的超重、肥胖与死亡率之间的关联也可能适用于有疾病或吸烟史的人群。
