Chinese researchers found Europeans genetically predisposed to getting up easily in the morning and having poor sleep duration had a higher risk of developing primary open-angle glaucoma (POAG).
Writing in Nature and Science of Sleep, Wuhan University and Chongqing Medical University researchers found that, in comparison with normal sleep, poor sleep duration results in a 1.66-times greater risk of POAG. Noting the literature’s conflicting findings around the connection between glaucoma and sleep, they said their use of Mendelian randomisation (MR) analysis determined the causal estimate of risk factors for disease outcomes by utilising genetic variants. In contrast to observational studies, the MR analysis made environmental confounding factors irrelevant, they said. However, since the prevalence of glaucoma and waking up in the early morning tend to increase with age, the higher risk of POAG in individuals who wake up early may also be attributable to age-related bias, they said.
In a separate UK Biobank-based study published in BMJ Open in 2022, a research team from China, Sweden and Iceland identified four different sleep patterns which increased the risk of different types of glaucoma: snoring, daytime sleepiness, insomnia and short/long duration sleep, either individually or jointly. Although no previous studies explored the association between sleep pattern and glaucoma risk, some found an increased risk with snoring and daytime sleepiness – which are both symptoms of obstructive sleep apnoea, said the team. Authors cited several possible reasons for the association, including insomnia and its related stress response stimulating neurotransmitter secretion and the autonomic nervous system, influencing the regulation of IOP and blood flow; plus the mechanical hypothesis of glaucoma development, which emphasises the importance of increased IOP and which is related to a supine position.
