Objective To explore the prevalence of poor social support and loneliness among people with chronic headache, and how these might be effect modifiers in the relationships between chronic headache and stress, medication overuse, and self-rated health. Background Poor social support and loneliness are consistently linked to worse health outcomes. There are few epidemiologic studies on their effect on headache. Methods The Danish Capital Region Health Survey, a cross-sectional survey, was conducted in 2017. Participants were asked about headache, pain medication use, social support, loneliness, perceived stress, and self-rated health. Data were accessed from sociodemographic registers. Logistic regression analyses were performed to test for effect modification. Results The response rate was 52.6% (55,185 respondents) and was representative of the target population. People with chronic headache were more likely to report poor social support and loneliness compared to those without chronic headache ( p < 0.0001 for both). Odds ratios for the combination of chronic headache and poor social support were very high for stress (odds ratio 8.1), medication overuse (odds ratio 21.9), and poor self-rated health (odds ratio 10.2) compared to those without chronic headache and with good social support. Those who reported both chronic headache and loneliness had a very high odds ratio for stress (odds ratio 14.4), medication overuse (odds ratio 20.1), and poor self-rated health (odds ratio 15.9) compared to those without chronic headache and low loneliness score. When adjusted for sociodemographic factors, poor social support and loneliness were not significant effect modifiers in almost all these associations. Loneliness was a significant effect modifier in the association between chronic headache and medication overuse, but exerted greater effect among those who did not report they were lonely. Conclusion Poor social support and loneliness were prevalent among people with chronic headache. The combination of chronic headache and poor social support or loneliness showed higher odds ratios for stress, medication overuse, and poor self-rated health compared to those with good social support and low loneliness scores. The effect of loneliness in the relationship between chronic headache and medication overuse warrants further study.
