Seasonal Variation of Serum Lipid Levels in Stable Renal Transplant Recipients

Abstract

Background/Aims: Seasonal variation in lipid levels is well described in the general population, but has not been examined in renal transplant recipients (RTR). We sought to determine whether seasonal differences exist in RTR, a group at high risk for hyperlipidemia. Methods: We reviewed our population of 920 adults, identifying primary allograft recipients with survival ≧1 year, stable function, and ≧1 pair of post-6 months ‘winter’ (December 21 to March 20) plus ‘summer’ (June 21 to September 22) fasting lipid measurements within the same year. Correlations between factors affecting lipids and lipid level change were followed by multiple linear regression analysis. Results: 243 patients contributed 344 pairs. When most recent seasonal pair (n = 243) and all pairs (n = 344) were separately analyzed, no seasonal total cholesterol difference (winter vs. summer) was seen (5.08 vs. 5.05 mmol/l, p = 0.80; 5.11 vs. 5.09 mmol/l, p = 0.81 respectively). Opposing variation was seen between hyperlipidemic and nonhyperlipidemic patients (0.08 vs. –0.18 mmol/l for winter minus summer, p = 0.02). In multivariate analysis, seasonal cholesterol variation was predicted by level (p < 0.0001) and hemoglobin change (p = 0.01), while triglyceride variation was predicted only by level (p = 0.01). Conclusion: RTR do not exhibit seasonal variation in lipids, unlike the general population. Factors unique to RTR such as immunosuppressive therapies may act to suppress any seasonal effects.