Mitochondrial dysfunction in patients with severe obstructive sleep apnea

Obstructive sleep apnea (OSA) is a prevalent sleep disorder characterized by intermittent hypoxia and oxidative stress, which can impair mitochondrial function and accelerate cellular aging. Mitochondrial DNA copy number (mtDNA-CN) is a useful biomarker of mitochondrial health. We conducted a cross-sectional study investigated differences in mtDNA-CN between individuals with severe OSA and those without severe OSA.

We analyzed 97 individuals who underwent overnight polysomnography and blood tests at Taichung Hospital, Taiwan, between March 1 and December 31, 2022. Leukocyte DNA was extracted to measure mtDNA-CN.

Among participants, 35 (36.1%) had severe OSA and 62 (63.9%) had non-severe OSA. Individuals with severe OSA exhibited significantly lower mtDNA-CN (675.5 ± 486.9 vs 1136.1 ± 955.0, P = 0.009) than those without severe OSA. Additionally, severe OSA was associated with higher preprandial blood glucose (109.5 ± 27.7 vs 92.9 ± 13.2 mg/dL, P < 0.001), HbA1c (6.2% ± 1.2% vs 5.5% ± 0.6%, P < 0.001), AST (25.2 ± 10.2 vs 21.6 ± 6.1 U/L, P = 0.045), ALT (32.2 ± 15.4 vs 25.1 ± 16.0 U/L, P = 0.006), and creatinine levels (0.93 ± 0.22 vs 0.77 ± 0.18 mg/dL, P = 0.001), along with a lower estimated glomerular filtration rate (81.1 ± 16.8 vs 96.2 ± 20.5 mL/min/1.73 m², P = 0.001). The patients with severe OSA had a significantly lower mtDNA-CN compared with those without severe OSA after adjustment of potential confounders (B = -692.8, 95% CI: -1190.4 to -195.3, P = 0.007).

Severe OSA was significantly associated with reduced mtDNA-CN after adjustment for potential confounders. These findings suggest a link between OSA and mitochondrial dysfunction, which may contribute to metabolic and systemic alterations. However, causal relationships cannot be established due to the cross-sectional design.