Roswall Nina, Li Yingjun, Sandin Sven, Ström Peter, Adami Hans-Olov, Weiderpass Elisabete
Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
Department of Diet, Genes and Environment, Danish Cancer Society Research Center, Copenhagen, Denmark.
Obesity (Silver Spring). 2017 Jan;25(1):215-222. doi: 10.1002/oby.21675. Epub 2016 Oct 21.
Most studies on obesity and mortality use a single anthropometric measure. Less is known about the effects of weight change on mortality. This study examined changes in body mass index (ΔBMI) and waist circumference (ΔWC) and subsequent all-cause and cause-specific mortality.
The study was conducted in the Women's Lifestyle and Health cohort, using self-reported anthropometric measures from 1991 to 1992 and 2003. Hazard ratios of mortality and 95% confidence intervals were calculated using Cox proportional hazards models. ΔBMI and ΔWC were examined in quartiles of absolute and relative change, with the second quartile (moderate gain) as the reference.
There was a higher risk of death in the first quartile of relative ΔBMI: HR 1.28 (1.04-1.56). Absolute ΔBMI suggested the same pattern, but the result was nonsignificant. ΔWC was not associated with mortality. In cause-specific analyses, the association remained significant for cancer mortality only. In sensitivity analyses excluding the first 5 years of follow-up, the association was, however, attenuated.
This study found a higher risk of death among women in the first quartile of relative ΔBMI compared with the second. It was driven by cancer mortality but may be ascribed to reverse causality. ΔWC was not associated with mortality.
大多数关于肥胖与死亡率的研究采用单一人体测量指标。关于体重变化对死亡率的影响，人们了解较少。本研究考察了体重指数变化（ΔBMI）和腰围变化（ΔWC）以及随后的全因死亡率和特定病因死亡率。
该研究在女性生活方式与健康队列中进行，使用了1991年至1992年以及2003年的自我报告人体测量指标。使用Cox比例风险模型计算死亡率的风险比和95%置信区间。按绝对和相对变化的四分位数考察ΔBMI和ΔWC，以第二四分位数（适度增加）作为参照。
相对ΔBMI的第一四分位数死亡风险更高：风险比1.28（1.04 - 1.56）。绝对ΔBMI显示出相同模式，但结果无统计学意义。ΔWC与死亡率无关。在特定病因分析中，仅癌症死亡率的关联仍然显著。在排除随访前5年的敏感性分析中，该关联有所减弱。
本研究发现，与第二四分位数相比，相对ΔBMI第一四分位数的女性死亡风险更高。这是由癌症死亡率驱动的，但可能归因于反向因果关系。ΔWC与死亡率无关。
