Association of Vitamin B12 Status with Polysomnographic Parameters and Cardiovascular Disease in Patients with Obstructive Sleep Apnoea.

Background: There are limited data on the association between B12 levels, objective sleep quality, and cardiovascular disease in patients with obstructive sleep apnoea (OSA). Therefore, the aim of our study was to assess vitamin B12 levels in a sleep clinic population in Crete, Greece, and investigate possible correlations with polysomnographic parameters and prevalent cardiovascular disease (CVD). Methods: In this cross-sectional study, data from 1468 recruited patients with OSA from the clinical database of the Sleep Disorders Center, Department of Respiratory Medicine, School of Medicine, University of Crete, were analyzed. OSA was defined as an apnoea-hypopnoea index ≥ 5 events per hour of sleep after type-1 Polysomnography (PSG). Data regarding anthropometrics, socio-demographics, and medical history was obtained. Logistic regression analysis was applied to examine the effect of vitamin B12 levels on PSG parameters and prevalent CVD after controlling for potential explanatory variables, including age, gender, obesity, smoking status, and co-morbidities. Results: The median vitamin B12 was 380.5 (301, 490) pg/mL. After adjustments, Vitamin B12 levels < 380.5 were associated with 24% higher odds of prolonged sleep latency (≥40 min) prevalence (OR = 1.240, 95% CI = 1.005-1.531, p = 0.045) and alterations in the proportion of NREM and REM sleep stages with 2.3 times higher likelihood of elevated NREM sleep > 80% of total sleep time (OR = 2.312, 95% CI = 1.049-5.096, p = 0.038) and 2.9 times higher likelihood of low REM sleep < 20% of total sleep time (OR = 2.858, 95% CI = 1.197-6.827, p = 0.018). Moreover, Vitamin levels < 380.5 were significantly associated with a 59.9% increase in the odds of prevalent CVD (OR = 1.599, 95% CI = 1.035-2.471, p = 0.034). Conclusions: In conclusion, our results suggest that vitamin B12 status may be associated with impaired objective sleep quality in OSA patients, potentially influencing prevalent CVD. However, further prospective research is needed to establish causality and elucidate the potential underlying mechanisms that could link vitamin B12 levels to various sleep parameters and cardiovascular disease in patients with OSA.