Fig. 2From: The risk of preterm birth in combinations of socioeconomic position and mental health conditions in different age groups: a Danish nationwide register-based cohort studyThe results of the first analysis of additive interaction between educational level and mental health conditions in pregnant women aged ≤23 (b), 24–30 (c), and ≥ 31 (d) years. a illustrates an example of how to read the attributable proportion (AP) in the bar chartsBack to article page