Research brief: Persistent social inequality in medicine use for headache among adolescents in Denmark 1991–2014

Background: Socioeconomic variation in adolescents' medicine use behaviour is an understudied issue. Objectives: To examine the association between socioeconomic background and medicine use for headache among adolescents, and how this association changes over time. Methods: Data stem from the Danish part of the international Health Behaviour in School-aged Children (HBSC) study 1991–2014 with data about parents' occupational social class (OSC) and self-reported medicine use for headache, n = 26,685. This study examined absolute social inequality (percent difference between high and low OSC) and relative social inequality (odds ratio for medicine use by OSC). Results: In total, 40.5% used medicine for headache in the past month. There was a significant increase from 32.3% in 1991 to 42.8% in 2002 (test for trend, p < 0.0001) and very little change 2002–2014. This pattern was similar in high, middle and low OSC. The prevalence of medicine use for headache in high, middle and low OSC was 36.2%, 41.5% and 44.8% (p < 0.0001). The OR (95% CI) for medicine use was 1.25 (1.18–1.324) in middle and 1.43 (1.33–1.54) in low OSC. Conclusions: Medicine use for headache increased 1991–2002 and remained stable 2002–2014. There was increasing medicine use for headache with decreasing OSC; this social inequality was persistent 1991–2014.