Heart rate variability and tension-type headache: A population-based cross-sectional study

Background: The relationship between tension-type headache (TTH) and autonomic functions is poorly understood, although TTH is one of the most prevalent disorders in the general population. The aim of this study was to investigate the direct and indirect effects of TTH on the autonomic functions measured by heart rate variability (HRV).Methods: This population-based cross-sectional study was carried out in the general population of Ulaanbaatar between July and September in 2020. After physical examination, trained researchers applied structured interviews to examine the remote history of TTH and mental distress, followed by a recording of HRV to detect autonomic activity. Psychological factors and the quality of life were measured using Hospital Anxiety Depression Scale (HADS), Pittsburgh Sleep Quality Index (PSQI), and the World Health Organization Quality of Life-Brief (WHOQOL-BREF). Binary logistic regression and GLM mediation model analysis were used to examine the effects of risk factors on the associations between TTH and autonomic functions.Results: Among participants (n = 217, mean age=41.8 +/- 11.5 years), a total of 117 (53.9%) participants had a remote history of TTH. The age and sex-adjusted prevalence was 43%. Groups did not differ statistically in the HRV indices. LF/HF (ratio of low-frequency to high frequency), the index of sympathovagal balance, was correlated with the HADS anxiety. TTH was associated with mental distress. Binary logistic regression analysis confirms the relationship suggesting that TTH was associated with increased likelihood of mental distress, and decreasing RMSSD (root mean square of the sum of the squares of differences between adjacent NN intervals) and pNN50 (NN50 divided by the total number of NN intervals) were the independent predictors of TTH. GLM mediation model indicated that the relationship between TTH and RMSSD was mediated by mental distress.Conclusions: The present study suggests that mental distress is a critical factor in the association between TTH and autonomic dysfunction. Additionally, our findings demonstrate the influence of age and gender on TTH. These results highlight the need to understand the mechanisms underlying pathophysiology to facilitate targeted and efficacious prevention and management approaches for TTH.