体重指数过低与总死亡率关系的前瞻性研究

A prospective study on the association between underweight and mortality from all cause

目的 探讨体重指数 (BMI)与全死因死亡率的关系。方法 对 1984～ 1986和 1992年进行心血管病危险因素调查的江苏省金坛县农民 3 2 0 4人 (男 145 7人 ,女 1747人 )随访 ,采用COX回归估计体重过低对全死因死亡率的相对危险性 (RelativeRisk ,RR)。结果 平均随访 12 .40年 ,共死亡30 7例 (男 187例 ,女 12 0例 ) ;不同体重指数组间死亡粗率差异显著 ;以BMI 18.5～ 2 4.9kg/m2 为参考组 ,体重过低 (BMI<18.5kg/m2 )组总死亡率的RR为 1.5 8(95 %CI 1.16～ 2 .14) ;吸烟和收缩压升高也是增加总死亡率的独立危险因素 ;排除随访早期 5年内因肿瘤死亡的 45例后 ,体重过低组总死亡率的RR仍达 1.49(95 %CI 1.0 7～ 2 .0 7)。结论 体重过低是增加总死亡率的危险因素 ,不能完全以吸烟、亚临床肿瘤的混杂效应来解释。

Objective To explore the association between underweight and mortality from all cause. Method We examined the relationship of underweight and mortality among subjects who participanted in the survey of cardiovascular risk factors (in 1984～1986 and in 1992). Relative Risks (RRs) were estimated from the COX proportional hazard model by using a BMI between 18.5～24 9 kg/m 2 as reference category. Results During an average 12.40 years follow up, we documented 307 deaths of which 158 were from cancer, 93 from cardiovascular diseases, and 56 from other causes. We observed a L shaped relation between BMI and overall mortality. ( P for trend <0.01); In multivariated analyses, we found that the RR of mortality for a BMI of <18 5 kg/m 2 was 1.58 (95% CI 1.16～2.14) as compared with the risk among subjects with BMI of 18.5～24 9 kg/m 2. The RR of overall mortality among subjects with BMI of <18.5 kg/m 2 was still significant after the exclusion of subjects who died from cancers during the first five years follow up. Conclusion Total mortality was increased among underweight people, and this association can not been completely explained by smoking and early deaths from cancer.