Background Previous studies have found the socioeconomic gradient in health among adolescents to be lower than that observed during childhood and adulthood. The aim of this study was to examine income-related inequalities in health and health-related behaviour across the lifespan in England to explore ‘equalisation’ in adolescence.

Methods We used five years of data (2006–2010) from the Health Survey for England to explore inequalities in six indicators: self-assessed general health, longstanding illness, limiting longstanding illness, psychosocial wellbeing, obesity and smoking status. We ran separate analyses by age/gender groups. Inequality was measured using concentration indices.

Results Our findings for longstanding illnesses, psychosocial wellbeing and obesity were consistent with the equalisation hypothesis. For these indicators, the extent of income-related inequality was lower among late adolescents (16–19 years) and young adults (20–24 years) compared to children and young adolescents (under 15 years), mid- and late-adults (25–44 and 45–64 years) and the elderly (65+ years). The remaining indicators showed lower inequality among adolescents compared to adults, but higher inequality when compared with children.

Conclusions Our work shows that inequalities occur across the life-course but that for some health issues there may be a period of equalisation in late adolescence and early adulthood.