Smoking Linked to Heightened IIH Risk

Idiopathic intracranial hypertension can cause headaches, tinnitus and vision changes due to increased pressure within the skull. Photo: Mark Dunbar, OD. Click image to enlarge. A review of literature from three virtual patient databases revealed that smoking may lead the way to a greater propensity for idiopathic intracranial hypertension (IIH).IIH is a rare cranial condition in which the accumulation of excessive spinal fluid around the brain increases pressure, leading to tinnitus, headaches and, of greatest ocular relevance, vision loss. While initial IIH-induced vision loss is temporary and often occurs as blind spots rather than complete blindness, it can become permanent if left untreated.A total of 8,098 recorded patients with IIH from 11 global studies—two studies each in the US, the UK, Turkey and Canada, as well as one in China, one in Germany and one in Denmark—were documented for tobacco use, with researchers noting potential association between the two factors. An additional 90,831 patients without IIH were incorporated as controls, within which 17.6% “were identified as current smokers,” the researchers described in their study.The researchers explained this link as smoking being “associated with increased blood viscosity and hypercoagulability, which could impair venous drainage and elevate intracranial venous pressure,” although they noted that “smoking may alternatively function as a surrogate marker for overall poorer health behaviours rather than directly contributing to IIH pathophysiology.” Another potential factor is the duration of time patients had been smoking, as a 1990 study cited in the paper mentioned that “patients with IIH were more likely to have initiated smoking at a younger age,” smoked for a longer time period of 10 years or longer, and smoked more (20 or greater) cigarettes in a day than those in the non-IIH control group.Despite possible methodological limitations of the study, the researchers described it as “the first meta-analysis to evaluate the association between smoking and IIH,” with a strong “consistency of the observed association across multiple continents.” They may, however, have been hindered by their classification of smokers and non-smokers based on descriptions provided in reviewed studies. Patients from studies in which smoking status was not explicitly stated were assumed to be current smokers, though it is unknown whether this was always the case.Because of its overall detriments, the consumption of tobacco products through smoking should be monitored as a factor for future and current ocular health problems. Its potential association with IIH, a rare and often life-altering condition, necessitates this on an even grander scale, particularly with nearly half (46%) of studied patients being current smokers. Click here for the journal source. Huang R, Mihalache A, Tao B, et al. Smoking and idiopathic intracranial hypertension: a meta-analysis. Eye (2026). [Epub ahead of print]. This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.