Study Finds Association Between Migraines, Ocular Motor Cranial Nerve Palsy

A study published in Scientific Reports found that migraines and incidence of ocular motor cranial nerve palsy (CNP) were significantly associated, especially in patients of younger age, men, smokers, and those with diabetes.

The study used the medical records in Korea’s National Health Insurance Service (NHIS), which insures about 97% of the population in Korea. The data of 4,053,824 patients aged 20 to 90 years were evaluated in this study. Patients were excluded if they had been previously diagnosed with ocular motor CNP, had missing data, or were newly diagnosed with CNP or died within 1 year of testing. All patients were followed up until December 31, 2018.

Definitions of ocular motor CNP, migraine, and all confounders were based on the International Classification of Diseases, Tenth Edition. Confounders for the relationship between ocular motor CNP and migraines were age, sex, smoking status, drinking amount, physical activity frequency, income status, and body mass index.

The participants were followed up for an equivalent of 33,323,032.76 person-years; 5806 (0.14%) developed ocular motor CNP and were assigned to the CNP group, whereas the remaining patients acted as controls. Mean (SD) follow-up duration was 8.22 (0.93) years.

Ocular motor CNP incidence was increased in the population who reported migraines compared with patients without migraines. Patients with migraines had an HR of 1.252 (95% CI, 1.088-1.440) for ocular motor CNP vs those without migraines. The HR was 1.166 (95% CI, 1.013-1.343) after full adjustment for comorbidities.

The researchers also found that certain subgroups were more likely to be diagnosed with ocular motor CNP if they had migraines. Patients who were younger than 65 years (HR, 1.267; 95% CI, 1.067-1.504), male (HR, 1.228; 95% CI, 1.000-1.122), smokers (HR, 1.426; 95% CI, 1.127-1.803), and had diabetes (HR, 1.378; 95% CI, 1.045-1.378) had a stronger association between diagnosis of ocular motor CNP and presence of migraines.

There were some limitations to this study. The researchers could not confirm a causal relationship between migraines and ocular motor CNP due to the retrospective nature of the study. Confounders such as medical history or current medications could not be accounted for in this analysis due to the nature of the NHIS records. Korean adults were the only included population, which may impede generalizability to other races.

The researchers concluded that their results demonstrated a significant association between incidence of ocular motor CNP and presence of migraines. They also concluded that certain subgroups were more susceptible to a diagnosis of ocular motor CNP than other subgroups. Further research on the possible pathophysiology underlying these associations should be explored, the authors noted.

Reference

Rhiu S, Han K, Yoo J, Park KA, Oh SY. Association between migraine and risk of ocular motor cranial nerve palsy. Sci Rep. 2022;12:20512. doi:10.1038/s41598-022-14621-z