School of Public Health, Sun Yat-sen University, Guangzhou, China.
Molecular Epidemiology Research Centre, Guangzhou No.12 Hospital, Guangzhou, China
BMJ Open. 2020 Dec 4;10(12):e039239. doi: 10.1136/bmjopen-2020-039239.
To examine the associations of change in body mass index (BMI) and waist circumference (WC) over an average of 4 years with subsequent mortality risk in middle-aged to older Chinese.
Prospective cohort study based on the Guangzhou Biobank Cohort Study.
Community-based sample.
17 773 participants (12 956 women and 4817 men) aged 50+ years.
Primary outcome measure was all-cause mortality. Secondary outcome measures were cardiovascular disease (CVD) and cancer mortality. Causes of death were obtained via record linkage, and coded according to the International Classification of Diseases (tenth revision).
1424 deaths (53.4% women) occurred in the 17 773 participants (mean age 61.2, SD 6.8 years) during an average follow-up of 7.8 (SD=1.5) years, and 97.7% of participants did not have an intention of weight loss . Compared with participants with stable BMI, participants with BMI loss (>5%), but not gain, had a higher risk of all-cause mortality (HR=1.49, 95% CI 1.31 to 1.71), which was greatest in those who were underweight (HR=2.45, 95% CI 1.31 to 4.59). Similar patterns were found for WC. In contrast, for participants with a BMI of ≥27.5 kg/m, BMI gain, versus stable BMI, was associated with 89% higher risk of all-cause mortality (HR=1.89, 95% CI 1.25 to 2.88), 72% higher risk of CVD mortality (HR=1.72, 95% CI 0.80 to 3.72) and 2.27-fold risk of cancer mortality (HR=2.27, 95% CI 1.26 to 4.10).
In older people, unintentional BMI/WC loss, especially in those who were underweight was associated with higher mortality risk. However, BMI gain in those with obesity showed excess risks of all-cause and cancer mortality, but not CVD mortality. Frequent monitoring of changes in body size can be used as an early warning for timely clinical investigations and interventions and is important to inform appropriate health management in older Chinese.
研究中年及以上中国人群平均 4 年的体重指数（BMI）和腰围（WC）变化与随后死亡率风险的相关性。
基于广州生物库队列研究的前瞻性队列研究。
社区样本。
17773 名参与者（12956 名女性和 4817 名男性），年龄在 50 岁以上。
主要结果测量是全因死亡率。次要结果测量是心血管疾病（CVD）和癌症死亡率。通过记录链接获得死亡原因，并根据国际疾病分类（第十版）进行编码。
在 17773 名参与者（平均年龄 61.2，标准差 6.8 岁）中，1424 人（53.4%为女性）在平均 7.8（标准差 1.5）年的随访中死亡，97.7%的参与者没有减肥的意愿。与 BMI 稳定的参与者相比，BMI 下降（>5%）而非增加的参与者全因死亡率风险更高（HR=1.49，95%置信区间 1.31 至 1.71），体重不足的参与者风险最大（HR=2.45，95%置信区间 1.31 至 4.59）。WC 也出现了类似的模式。相比之下，对于 BMI≥27.5kg/m2 的参与者，BMI 增加与 BMI 稳定相比，全因死亡率风险增加 89%（HR=1.89，95%置信区间 1.25 至 2.88），CVD 死亡率风险增加 72%（HR=1.72，95%置信区间 0.80 至 3.72），癌症死亡率风险增加 2.27 倍（HR=2.27，95%置信区间 1.26 至 4.10）。
在老年人中，非故意的 BMI/WC 下降，尤其是体重不足者，与死亡率风险增加相关。然而，肥胖者 BMI 增加与全因和癌症死亡率风险增加相关，但与 CVD 死亡率风险无关。频繁监测身体大小的变化可作为及时进行临床调查和干预的早期预警，对指导中国老年人进行适当的健康管理非常重要。
