Vitamin D deficiency in patients evaluated for obstructive sleep apnea: is it associated with disease severity?

PURPOSE: The aim of the present study was to assess vitamin D levels in a large cohort of OSA patients and to investigate possible correlations with clinical and polysomnographic parameters. METHODS: In this cross-sectional study, 685 consecutive patients underwent type 1 polysomnography (PSG) for OSA diagnosis. They were grouped according to apnea-hypopnea index (AHI) as mild, moderate, and severe. Patients with AHI < 5 served as controls. Demographic, PSG data, and serum levels of vitamin D were measured and compared between groups. RESULTS: OSA was diagnosed in 617 of the patients (90%). Of those, 94 (15%) had mild OSA, 150 (24%) moderate OSA, and 373 (61%) severe OSA. The risk of vitamin D deficiency (< 20 ng/mL) was observed in 38% of the cohort. OSA patients had lower vitamin D levels compared to controls (23 ng/mL vs 26 ng/mL, p = 0.006). The lowest levels of vitamin D [mean 21] (p < 0.001 among all groups) and the higher prevalence for vitamin D deficiency (45%) were observed in severe OSA patients. After multiparametric adjustments for age, gender, obesity, and comorbidities, severe OSA showed significant independent associations with the risk of vitamin D deficiency [OR (95% CI) 2.002 (1.049-3.819), p = 0.035]. CONCLUSIONS: A large proportion of patients referred for OSA evaluation had vitamin D deficiency, which was independently associated with severe OSA. However, further research is needed in order to determine the role of vitamin D in OSA patients.

Cardiovascular Effect and Symptom Profile of Obstructive Sleep Apnea: Does Sex Matter?

STUDY OBJECTIVES: To evaluate the influence of sex on obstructive sleep apnea (OSA)-related symptoms and prevalent cardiovascular disease (CVD) in a large clinical population of patients. METHODS: A total of 6,716 patients (mean age 52 years, 24% women) had undergone diagnostic polysomnography and completed the Epworth Sleepiness Scale (ESS), Athens Insomnia Scale, and Beck Depression Inventory. We investigated the predictive value of sex on associated symptoms and prevalent cardiovascular disease, after adjustment for relevant confounding factors including age, obesity, and comorbidities. RESULTS: Most of the patients (90%) had OSA (apnea-hypopnea index [AHI] ≥ 5 events/h), and 66% were obese. Women were older than men and had a higher body mass index; however, men had a thicker neck circumference, a higher waist-to-hip ratio, and increased OSA severity (AHI 36 versus 27 events/h, P < .001). Female sex independently predicted prevalent CVD after adjustment for confounders (odds ratio [95% CI] 1.476 [1.154-1.887], P = .002). Men independently were more likely to report driving problems (3.359 [2.470-4.569], P < .001) and excessive daytime sleepiness (ESS ≥ 16) (1.355 [1.036-1.773], P = .027). Furthermore, female sex was an independent predictive factor for depressive symptoms (2.473 [1.831-3.340], P < .001), frequent awakenings (1.703 [1.323-2.192], P < .001), nocturia (1.727 [1.340-2.226], P < .001) and morning headaches (1.855 [1.488-2.326], P < .001). CONCLUSIONS: Females referred for sleep studies were more likely to exhibit CVD and less likely to complain of typical OSA symptoms than males in this large clinical patient cohort.