Preliminary establishment of reference interval for non-fasting serum triglycerides among healthy middle-aged and elderly people in some communities Beijing

Objective To establish the reference interval of serum triglyceride (TG) for 4 hours after meal in healthy middle and old people of Beijing community, and to provide the diagnostic basis for the judgment of dyslipidemia after meal. Methods Selected 369 elderly people from January to October 2018 in the health examination of Guang′anmen Hospital of the Chinese Academy of Traditional Chinese Medicine. The subjects collected fasting venous blood samples in the morning the next day after fasting for 12 hours, then ate a standard breakfast that conformed to the local dietary habits, and collected venous blood samples again 4 hours after eating. Serum TG levels were measured 4 h after meal using AU5822 fully automatic biochemical analyzer and matching reagents. The comparison of postprandial TG between different age and sex groups was statistically significant using the nonparametric test of two independent samples, and the comparison between postprandial and fasting TG using the nonparametric test of two paired samples with P<0.05 as the difference. The 95% confidence interval was calculated using a nonparametric method according to the relevant requirements of the CLSI EP28-A3c file, and the reference interval was expressed as P2.5, P97.5. Results The median 4-hour post-prandial TG of the middle-aged and elderly aged 45-59 years and those aged ≥ 60 years at health checkups were 1.65 (1.25, 2.13) mmol/L and 1.58 (1.25, 2.00) mmol/L, there was no significant difference between the two groups (Z=-1.040, P>0.05). There was no statistical difference between males 1.69 (1.22, 2.31) mmol/L and females 1.63 (1.26, 2.12) mmol/L at 4 hours postprandial TG levels in the 45-59 year-old group (Z=-0.179, P>0.05),there was also no statistical difference between 1.64 (1.22, 2.06) mmol/L for men and 1.53 (1.28, 1.99) mmol/L for women aged 60 years or older (Z=-0.256, P>0.05).Compared with the median fasting TG of 1.05 (0.87, 1.29) mmol/L, the median serum TG of 1.61 (1.25, 2.09) mmol/L at 4 hours after meal was significantly increased (Z=-16.449, P<0.01). The difference between postprandial and fasting was 0.52 (0.30, 0.85) mmol/L.The reference range of serum TG at 4 hours after meal was 0.82 to 3.02 mmol/L. Conclusion In this study, the reference range of serum triglycerides for 4 hours after meal was established in some healthy elderly population groups in Beijing. Key words: Non-fasting serum Triglyceride; Healthy population; Middle-aged and elderly people; Reference range