People with an impaired sense of smell face a 19 percent higher risk of developing migraines than those with normal olfactory function, a new study has found.
The finding comes from a research team led by Prof. Jo Jae-hun of the Department of Otorhinolaryngology-Head and Neck Surgery at Konkuk University Medical Center, working with researchers at Indiana University School of Medicine. The team tracked more than 3.4 million Korean adults from 2011 to 2020 using data from the National Health Insurance Service.
The research team drew its study population from roughly 4.23 million adults aged 20 and older who underwent national health screenings in 2009. After excluding those already diagnosed with migraines or lacking complete screening records, the team divided participants into two groups: 8,270 people diagnosed with olfactory disorders between 2006 and 2008, and a control group of 3,426,923 people. Migraine incidence was then tracked across both groups.
During the follow-up period, the migraine incidence rate in the olfactory disorder group was 21.85 per 1,000 person-years, compared with 16.47 in the control group. Even after adjusting for age, sex, body mass index, smoking, alcohol consumption, physical activity, diabetes, hypertension, dyslipidemia and kidney function, the olfactory disorder group still showed a 19 percent higher risk of developing migraines (hazard ratio 1.19; 95% confidence interval 1.13–1.25).
A separate analysis that accounted for cases where observation ended before a migraine diagnosis — due to death or relocation — produced a similar hazard ratio of 1.20 (95% confidence interval 1.14–1.26). The association between olfactory disorders and migraines held consistently across all subgroups, including those defined by age, sex, body mass index, smoking status, alcohol use and comorbidities. However, the research team noted that the study does not establish a causal relationship between olfactory disorders and migraines, and said further research into the association is needed.
The team focused on the anatomical proximity of the olfactory nerve, which processes smell, and the trigeminal nerve, which transmits pain and sensory signals, within the nasal cavity. Migraines are understood to arise when the trigeminal nerve is stimulated and affects the vascular system. The researchers suggest that diminished olfactory function may disrupt how the trigeminal nerve processes sensory input, potentially creating conditions that make migraines more likely.
Both olfactory disorders and migraines significantly reduce quality of life. Olfactory disorders affect between 3.2 and 22 percent of the general population, while migraines are among the most common neurological conditions worldwide — estimated to have occurred more than 1.1 billion times globally in 2019 alone.
The co-occurrence of smell loss and headaches drew wide attention during the COVID-19 pandemic, but most related research focused on COVID-19 infection specifically. The team said it undertook the study after noting the absence of population-based research examining whether a link between the two conditions existed before the pandemic. The findings were published in volume 66, issue 7 (pages 1587–1596) of the international journal Headache in 2026, with Jo serving as corresponding author and leading the study's design and analysis. Headache is the official journal of the American Headache Society and is classified as a top-quartile (Q1) publication in the field of neurology by journal evaluation agencies.
kty@heraldcorp.com
