Background and objectives: Although obesity is recognized as a risk factor of migraine chronification, its longitudinal impact on migraine onset remains unclear. The aim of this study was to investigate the association between obesity and the risk of developing migraine in a longitudinal setting.
Methods: We conducted a population-based prospective cohort study using data from the Korean National Health Insurance Service. Individuals aged 20-39 years who underwent health examinations between 2009 and 2012 were enrolled, excluding those with a history of migraine, missing data, or a migraine diagnosis within the first year. Participants were followed to the end of 2018. Body mass index (BMI) was categorized into 5 groups and waist circumference (WC) into 6 levels. Outcome was the first migraine claim (International Classification of Diseases, Tenth Revision code G43). We evaluated the associations of BMI and WC with the risk of migraine using multivariable Cox proportional hazard regression models. Interaction analyses were conducted based on demographic and lifestyle factors.
Results: Among 6,106,560 individuals included (mean age: 30.6 ± 4.98 years; 39% female), the risk of migraine increased with increasing BMI (adjusted hazard ratio [aHR] 1.001 [95% CI 0.991-1.010], 1.047 [95% CI 1.040-1.055], 1.087 [95% CI 1.079-1.094], and 1.121 [95% CI 1.106-1.136] for underweight, overweight, stage 1 obesity, and stage 2 obesity, respectively, compared with normal BMI) and WC (aHR 0.913 [95% CI 0.906-0.921], 0.969 [95% CI 0.960-0.978], 1.022 [95% CI 1.010-1.034], 1.048 [95% CI 1.032-1.065], and 1.048 [95% CI 1.030-1.067] for levels 1, 2, 4, 5, and 6, respectively, compared with level 3). This dose-dependent relationship remained significant for WC after adjusting for BMI, but not vice versa. A stronger association between abdominal obesity and migraine risk was observed in younger individuals (<30 years) (p for interaction = 0.0181), nonsmokers (p for interaction = 0.0341), and heavy drinkers (p for interaction = 0.0143).
Discussion: Obesity was associated with an increased risk of migraine in young adults in a dose-dependent manner, with WC demonstrating a more robust independent association than BMI. Owing to the limitations of claims data, our study needs cautious interpretation and further validation in studies with detailed clinical information.