Longitudinal associations of lipid profiles with sleep disorders in patients with Parkinson's disease

To examine the associations of apolipoprotein E (APOE) carrier status and lipid profiles with sleep disorders, including excessive daytime sleepiness (EDS) and probable rapid eye movement sleep behavior disorder (pRBD), among patients with early Parkinson's disease (PD) over 5-year follow-up periods. The Parkinson's Progression Markers Initiative is a multicenter cohort study based on an ongoing and open-ended registry. Data from baseline and 5-year follow-up visits from participants of de novo PD were analyzed. Longitudinal associations of APOE carrier status and lipid profiles with sleep disorders were estimated via linear mixed-effects models. A total of 657 participants with complete APOE genotypes were enrolled at baseline. Among them, 153 (25.3%) had available lipid profiles at baseline. In the linear mixed-effects models, baseline APOE ε2/ε3/ε4 carrier status did not exhibit significant associations with EDS and pRBD (all p > 0.05) in all models. However, reduced high-density lipoprotein (HDL) and elevated triglycerides (TG) were associated with developing EDS (β = -0.04, 95% CI: -0.07, -0.00) and pRBD (β = 0.01, 95% CI: 0.00, 0.02) in PD patients, respectively. In the APOE ε4+ subgroup, decreased HDL and increased TG displayed substantial associations with developing EDS and sleep disorders (all p < 0.05) in all models, respectively, whereas no significant differences were noted in the APOE ε4- subgroup (all p > 0.05). Our study did not demonstrate a clear association between APOE ε2/ε3/ε4 and sleep disorders in PD patients. However, the presence of APOE ε4 was associated with changes in lipid profiles, notably affecting TG and HDL levels.