Abbas Ali Tam, Feride Pınar Altay, Pervin Demir, Didem Özdemir, Oya Topaloğlu, Reyhan Ersoy, Bekir Çakır
Endocrinology Research and Practice - 2026;30(1):37-45
Objective: The purpose of this study is to evaluate seasonal variations in serum lipids, which are a well-defined cardiovascular risk factor. Methods: Medical records of 96 019 individuals (128 310 measurements) during February 2019 and May 2024 were surveyed. Serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and non-HDL-C were evaluated, and TG/glucose (TyG) index and TG/HDL-C ratios were calculated for each individual. Dyslipidemia was defined as serum TC >= 200 mg/dL, TG >= 150 mg/dL, HDL-C <= 40 mg/dL, and LDL-C >= 130 mg/dL. Seasonal variations in lipid parameters, TyG index, and TG/HDL have been investigated. Changes in these parameters during defined holidays and periods were also evaluated. Results: All lipid parameters except HDL-C (TC, LDL-C, TG, non-HDL-C, TG/HDL ratio, and TyG) were higher in winter (all P-values <.001). The number of people with dyslipidemia was also higher in the winter. Triglyceride and TyG indices were significantly higher in the period including the first week of January (following the new year) and the weeks following religious holidays (P < .001). Non-HDL-C, TC, LDL-C, TG/HDL ratio, and TyG index increased significantly in the transition from summer and/or autumn to winter. Conclusion: Serum lipid levels, TyG index, and TG/HDL ratio showed seasonal variation, in addition to an increased risk of dyslipidemia in winter. These findings suggest that seasonal variations in lipid levels might contribute to an increased risk of cardiovascular disease in winter. Therefore, it is appropriate to consider seasonality in managing and diagnosing dyslipidemia in clinical practice.
