关键词: 小而密低密度脂蛋白, 低密度脂蛋白胆固醇, 高密度脂蛋白胆固醇, 三酰甘油, 总胆固醇, 非空腹, 参考区间上限

Abstract:

Objective To investigate the postprandial blood lipid levels [total cholesterol（TC），triglyceride（TG），high-density lipoprotein cholesterol（HDL-C），low-density lipoprotein cholesterol（LDL-C），small and dense low-density lipoprotein cholesterol（sd-LDL-C），non-high-density lipoprotein cholesterol（non-HDL-C），remnant lipoprotein cholesterol（RLP-C），the percentage of small and dense low-density lipoprotein（sd-LDL%）and the ratio of TG/HDL-C] in healthy adults under normal dietary conditions，and to establish the reference cut-off values. Methods A total of 1 417 healthy subjects who underwent routine physical examinations from June 2024 to April 2025 at Jiangwan Hospital in Hongkou District，Shanghai，were enrolled. They were classified by gender and age. For males，the groups were 18-40 years old，41-60 years old and >60 years old. For females，the groups were 18-30 years old，31-45 years old，46-55 years old and ≥56 years old. The samples were collected from all the subjects for 2-4 h after lunch. TC，TG，HDL-C，LDL-C and sd-LDL-C were determined，and non-HDL-C，RLP-C，sd-LDL% and the ratio of TG/HDL-C were calculated. The 90th percentile （P₉₀）of each item was statistically analyzed，and the upper limits of reference intervals were established. Results There was statistical significance in postprandial TC，TG，HDL-C，non-HDL-C，sd-LDL% and the ratio of TG/HDL-C among males and females（P<0.05），while there was no statistical significance in postprandial LDL-C，sd-LDL-C and RLP-C levels（P>0.05）. The levels of sd-LDL-C and sd-LDL% were increased with age in both males and females（P<0.05）. The levels of TC，TG，LDL-C，non-HDL-C，sd-LDL-C and sd-LDL% and the TG/HDL-C ratio in postprandial blood of females increased with age （P<0.001）. The levels of postprandial sd-LDL-C and TG and the ratio of TG/HDL-C，non-HDL-C were positively correlated（r values were 0.512，0.505 and 0.421，respectively，P<0.01），and negatively correlated with HDL-C（r=-0.276，P<0.01）. Among healthy subjects≤45 years old，the blood lipid levels of males，except for HDL-C，were lower than those of females in the same age group（P<0.01），and the other blood lipid levels were higher than those of females（P<0.01）. Among healthy subjects>55 years old，the TC，TG，HDL-C，LDL-C，non-HDL-C，RLP-C，sd-LDL-C levels and the ratio of TG/HDL-C were higher in females than in males（P<0.05）. After excluding the subjects with TG >5 mmol·L^-1，the upper limits of the 90% reference interval for postprandial sd-LDL-C and sd-LDL% were as follows：for males ≤60 years old，<1.61 mmol·L^-1 and <52.1%；for males >60 years old，<1.71 mmol·L^-1 and <65.7%；for females ≤45 years old，<1.39 mmol·L^-1 and <43.3%；for females >45 years old，<1.71 mmol·L^-1 and <52.7%. Conclusions The 90% reference upper limit values of blood lipid indicators after daily ordinary meals for healthy adults of different genders and ages have initially established. In a non-fasting state，sd-LDL-C and sd-LDL% are indicators reflecting the blood lipid metabolism changes with aging in males. There are differences in blood lipid metabolism among females of different age groups.

Key words: Small and dense low-density lipoprotein, Low-density lipoprotein cholesterol, High-density lipoprotein cholesterol, Triglyceride, Total cholesterol, Non-fasting, Upper limit of reference interval