Department of Nutrition and Food Hygiene, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China.
Department of Epidemiology, Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, Guangzhou, China.
Clin Nutr. 2023 Dec;42(12):2328-2337. doi: 10.1016/j.clnu.2023.09.027. Epub 2023 Oct 6.
BACKGROUND & AIMS: Polyunsaturated fatty acids (PUFAs) may play a vital role in maintaining skeletal muscle mass in the aged population. This study investigated the longitudinal relationship between the concentrations of erythrocyte membrane PUFAs and age-related changes in skeletal muscle mass over an average 6.5 years of follow-up in a Chinese middle-aged and older adult population.
A total of 1494 participants aged 57.4 ± 4.7 years were included in this study. Skeletal muscle mass was determined using dual-energy X-ray absorptiometry. Per year percent changes in the skeletal muscle index (Δ% SMI), appendicular skeletal muscle index (Δ% ASMI), and total body lean mass index (Δ% TBLMI) from baseline were calculated. Concentrations of total and individual cis-n-3 and cis-n-6 PUFAs of the erythrocyte membrane were determined using gas-liquid chromatography.
Fully adjusted linear regression models showed that per unit increases in the concentrations of C18:2 n-6, C20:4 n-6, C22:4 n-6, and total n-6 PUFAs resulted in increases of 0.022%-0.155 % in the Δ% SMI (P for linearity: <0.001-0.006). Restricted cubic spline analysis revealed an inverted U-shaped relationship between the concentrations of C20:2 n-6, C22:5 n-3, C22:6 n-3, and total n-3 PUFAs and the Δ% SMI (P for non-linearity: <0.001-0.036). In addition, an inverted U-shaped curve was also detected for the relationships of the linoleic acid/α-linolenic acid ratio (P for non-linearity = 0.010) and n-6/n-3 PUFA ratio (P for non-linearity = 0.013) with the Δ% SMI, with the Δ% SMI peaking at respective ratios of 124.96 and 3.69. Similar associations were revealed by the Bayesian kernel machine regression model. No interaction effect was detected between the individual PUFAs for the Δ% SMI in the bivariate exposure-response analysis. Overall, similar results were observed for the Δ% ASMI and Δ% TBLMI.
The associations between different individual PUFAs and age-related muscle loss in middle-aged and older adults may be different. Our results suggest that high concentrations of erythrocyte membrane n-6 PUFAs may be correlated with less skeletal muscle mass loss, whereas extremely high concentrations of n-3 PUFAs may be correlated with more muscle loss.
多不饱和脂肪酸（PUFAs）在维持老年人群的骨骼肌质量方面可能起着至关重要的作用。本研究旨在探讨红细胞膜 PUFAs 浓度与中国中老年人群骨骼肌质量随年龄变化的纵向关系，平均随访时间为 6.5 年。
共纳入 1494 名年龄为 57.4±4.7 岁的参与者。采用双能 X 射线吸收法测定骨骼肌质量。计算基线时骨骼肌指数（Δ%SMI）、四肢骨骼肌指数（Δ%ASMI）和全身瘦体重指数（Δ%TBLMI）的每年百分比变化。采用气相色谱法测定红细胞膜总 cis-n-3 和 cis-n-6 PUFAs 及各单体 cis-n-3 和 cis-n-6 PUFAs 的浓度。
完全调整的线性回归模型显示，红细胞膜 C18:2 n-6、C20:4 n-6、C22:4 n-6 和总 n-6 PUFAs 浓度每增加一个单位，Δ%SMI 增加 0.022%-0.155%（线性 P<0.001-0.006）。限制性立方样条分析显示，红细胞膜 C20:2 n-6、C22:5 n-3、C22:6 n-3 和总 n-3 PUFAs 浓度与Δ%SMI 之间呈倒 U 型关系（非线性 P<0.001-0.036）。此外，还检测到亚油酸/α-亚麻酸比值（P 非线性=0.010）和 n-6/n-3 PUFA 比值（P 非线性=0.013）与Δ%SMI 之间的倒 U 型曲线，Δ%SMI 在比值分别为 124.96 和 3.69 时达到峰值。贝叶斯核机器回归模型也得到了类似的结果。在双变量暴露反应分析中，个体 PUFAs 对Δ%SMI 没有交互作用。总体而言，对于Δ%ASMI 和Δ%TBLMI 也观察到了类似的结果。
不同个体 PUFAs 与中老年人群肌肉衰老之间的关系可能不同。我们的研究结果表明，红细胞膜 n-6 PUFAs 浓度高可能与骨骼肌质量损失较少有关，而 n-3 PUFAs 浓度极高可能与肌肉损失较多有关。
