Department of Epidemiology and Preventive Medicine, University of Regensburg, Regensburg, Germany.
Ludwig-Maximilians-Universität München, University Center for Health Sciences at the Klinikum Augsburg (UNIKA-T), Augsburg, Germany.
Am J Clin Nutr. 2021 Mar 11;113(3):639-646. doi: 10.1093/ajcn/nqaa339.
Fat mass and fat-free mass may play independent roles in mortality risk but available studies on body composition have yielded inconsistent results.
The aim was to determine the relations of body fat mass and fat-free mass to risk of mortality.
In pooled data from 7 prospective cohorts encompassing 16,155 individuals aged 20 to 93 y (median, 44 y), we used Cox regression and restricted cubic splines to estimate HRs and 95% CIs for the relation of body composition, measured by bioelectrical impedance analysis, to total mortality. We adjusted for age, study, sex, ethnicity, history of diabetes mellitus, education, smoking, physical activity, and alcohol consumption.
During a median follow-up period of 14 y (range, 3-21 y), 1347 deaths were identified. After mutual adjustment for fat mass and fat-free mass, fat mass showed a J-shaped association with mortality (overall P value < 0.001; P for nonlinearity = 0.003). Using a fat mass index of 7.3 kg/m2 as the reference, a high fat mass index of 13.0 kg/m2 was associated with an HR of 1.56 (95% CI: 1.30, 1.87). In contrast, fat-free mass showed an inverse association with mortality (overall P value < 0.001; P for nonlinearity = 0.001). Compared with a low fat-free mass index of 16.1 kg/m2, a high fat-free mass of 21.9 kg/m2 was associated with an HR of 0.70 (95% CI: 0.56, 0.87).
Fat mass and fat-free mass show opposing associations with mortality. Excess fat mass is related to increased mortality risk, whereas fat-free mass protects against risk of mortality. These findings suggest that body composition provides important prognostic information on an individual's mortality risk not provided by traditional proxies of adiposity such as BMI.
脂肪量和去脂量可能在死亡风险中起独立作用，但现有的身体成分研究结果并不一致。
目的是确定体脂肪量和去脂量与死亡率的关系。
我们使用 Cox 回归和限制立方样条，对来自 7 个前瞻性队列（年龄 20-93 岁，中位数 44 岁，共 16155 人）的汇总数据进行分析，估计体成分（通过生物电阻抗分析测量）与全因死亡率的关系的 HRs 和 95%CI。我们调整了年龄、研究、性别、种族、糖尿病史、教育程度、吸烟、身体活动和饮酒。
在中位数为 14 年（范围为 3-21 年）的随访期间，确定了 1347 例死亡。在相互调整脂肪量和去脂量后，脂肪量与死亡率呈 J 形关联（总体 P 值<0.001；非线性 P 值=0.003）。以脂肪量指数 7.3 kg/m2 为参考，高脂肪量指数 13.0 kg/m2 与 HR 为 1.56（95%CI：1.30，1.87）相关。相比之下，去脂量与死亡率呈负相关（总体 P 值<0.001；非线性 P 值=0.001）。与低去脂量指数 16.1 kg/m2 相比，高去脂量 21.9 kg/m2 与 HR 为 0.70（95%CI：0.56，0.87）相关。
脂肪量和去脂量与死亡率呈相反的关系。过多的脂肪量与死亡风险增加相关，而去脂量则可降低死亡风险。这些发现表明，身体成分提供了有关个体死亡率风险的重要预后信息，这些信息不能通过 BMI 等传统肥胖指标提供。
