Obstructive sleep apnoea ups risk of optic neuropathy
Individuals with obstructive sleep apnoea (OSA) are at higher risk of developing optic neuropathy compared with those who do not have the condition, a study has found.
Researchers identified 5,129 individuals with OSA and 51,290 controls from the Taiwan Longitudinal Health Insurance Database. Mean age of the entire cohort was 48.2 years, and the majority (65.6 percent) were male. Compared with controls, OSA patients were more likely to have comorbid hypertension, diabetes, atherosclerosis, coronary artery disease, hyperlipidaemia and migraine (p<0.0001 for all).
Optic neuropathy occurred in 30 OSA patients vs 132 controls. Cox proportional hazard analysis revealed that OSA was associated with about a twofold higher risk of optic neuropathy (adjusted hazard ratio [HR], 1.95; 95 percent CI, 1.30–2.92). This association persisted regardless of the presence of comorbidity. The risk was especially higher in subgroups of patients aged <45 years (adjusted HR, 4.21; 1.93–9.18) and those who were male (adjusted HR, 1.93; 1.17–3.18).
Of note, treatment with continuous positive airway pressure (CPAP) showed no protective effect on the risk. The adjusted HRs for developing optic neuropathy vs controls were 2.31 (1.07–4.99) in the group of OSA patients who underwent CPAP and 1.82 (1.12–2.97) in the group who did not receive treatment.
In a separate cohort of 4,143 individuals with optic neuropathy and 41,430 controls, the ophthalmic condition was associated with an elevated risk of OSA (adjusted HR, 1.45; 1.02–2.07). The risk was particularly higher in subgroups of individuals aged 45–64 years (adjusted HR, 1.76; 1.08–2.86) and those who were male (adjusted HR, 1.55; 1.01–2.39).
Researchers postulated that mechanisms by which OSA may increase the risk of optic neuropathy may involve hypoxia, vascular dysregulation, and increased intracranial pressure and vasoactive substances (vascular endothelial growth factor and endothelin-1).
Additional studies with a larger sample size are needed to clarify the efficacy of treatment for OSA in reducing the risk of optic neuropathy, they added.