Sleep Status and Low-Density Lipoprotein Particle Size in a General Japanese Female Population: The Mima Study

OBJECTIVE: This study investigated the relationship between sleep adequacy and small dense low-density lipoprotein (sdLDL) in a Japanese population. SUBJECTS AND METHODS: Clinical data, including atherosclerotic risk factors, in addition to the mean LDL particle size (LDL-PS) measured by gel electrophoresis, were evaluated in 136 community-dwelling female subjects (40-80 years old). The sleep status was self-reported and the subjects were divided into those who had inadequate sleep (≤6 or ≥9 h of sleep) and had adequate sleep (7-8 h). RESULTS: The mean LDL-PS was significantly smaller in subjects with inadequate sleep [n = 68, 26.4 ± 0.4 (SD) nm] than in those with adequate sleep (n = 68, 26.6 ± 0.4 nm, p < 0.05). This difference remained significant and independent after adjusting for confounders (β = 0.15-0.19, p < 0.05). CONCLUSION: Sleep adequacy was associated with the presence of sdLDL, while the influence of the sleep status on LDL-PS was minor in this population. Further research on the associations among sleep, sdLDL and cardiovascular disease prevention is warranted.