Objective: To evaluate the associations between body mass index (BMI) and both total and cause-specific mortality. Methods: After excluding participants with heart disease, stroke, cancer, chronic obstructive pulmonary disease, and diabetes at baseline study, 428 593 participants aged 30-79 in the China Kadoorie Biobank study were chosen for this study. Participants were categorized into 9 groups according to their BMI status. Cox regression analysis was used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) of mortality on BMI. Results: Among 3 085 054 person-years of the follow-up program between 2004 and 2013 (median 7.2 years), a total of 7 862 men and 6 315 women died. After adjusting for known or potential confounders, an increased risks of all-cause deaths were shown among participants with a BMI less than 18.5 (HR=1.40, 95%CI: 1.31-1.50), between 18.5-20.4 (HR=1.11, 95%CI: 1.05-1.17), and more than 35.0 (HR=2.05, 95%CI: 1.60-2.61), when compared to those with BMI between 20.5-22.4. Ranges of BMI with lower risk of cause-specific mortality were: 18.5-23.9 for ischemic heart disease, <26.0 for cerebro-vascular disease, 26.0-34.9 for cancers, and 24.0-25.9 for respiratory diseases. Conclusions: In this large prospective study, both underweight and obesity were associated with the increased total and certain cause-specific mortality, which were independent from other risk factors of death. Programs related to extensive follow-up, thorough analysis BMI and the risks of incidence on major chronic diseases all need to be developed, in order to better understand the impact of BMI on human health.
目的：探讨BMI与全死因死亡和缺血性心脏病、脑血管病、恶性肿瘤、呼吸系统疾病等死因别死亡的前瞻性关联。 方法：利用中国慢性病前瞻性研究队列的10个地区人群数据，剔除基线时自报患有冠心病、脑卒中、恶性肿瘤、慢性阻塞性肺病和糖尿病的个体后，纳入基线时30 ～79岁的研究对象共428 593人。利用Cox比例风险模型计算9组BMI人群死亡风险比值（HR）及其95%CI。 结果：研究人群累计随访3 085 054人年（平均随访7.2年）。随访期间男性7 862人、女性6 315人死亡。多因素调整后，与BMI (kg/m(2)）为20.5~ 22.4的人群相比，BMI <18.5（HR＝ 1.40，95%CI：1.31~ 1.50）、BMI为18.5~ 20.4 （HR＝1.11，95%CI：1.05~ 1.17）和BMI≥35.0 （HR ＝ 2.05，95%CI：1.60～2.61）的人群全死因死亡风险升高。各疾病死亡风险相对较低的BMI （kg/m(2)）范围：缺血性心脏病为18.5~ 23.9，脑血管病为<26.0，恶性肿瘤为26.0~ 34.9，呼吸系统疾病为24.0~ 25.9。 结论：低体重和肥胖人群的全死因死亡与死因别死亡风险升高。人群队列更长期的随访以及更多关于BMI与主要慢性病发病风险的评估，将有助于全面了解BMI对人群健康的影响。.
Keywords: Body mass index; Chronic disease; Mortality; Prospective study.