Pathways of socioeconomic inequalities in gingival bleeding among adolescents

To explore the pathways through which the socioeconomic inequalities may influence gingival bleeding in adolescents, assessing the direct and indirect effects of material and psychosocial variables.

This cohort study followed a multistage, random sample of 1134 12-year-old adolescents from 20 public schools of Santa Maria, a city in southern Brazil. The percentage of teeth with gingival bleeding was recorded according to the Community Periodontal Index criteria (scored as healthy or bleeding) at baseline and at 2-year follow-up. Biological (dental plaque, caries, and dental crowding), material (socioeconomic position [SEP] operationalized as family income and parents' education), psychosocial (parents' religiosity, self-rated health, and happiness) and behavioural (use of dental service by adolescents) factors were collected at baseline. Structural equation modelling (SEM) was guided by the adapted Commission on the Social Determinants of Health model linking material, psychosocial, biological, and behaviour variables to health. The SEM was employed to estimate standardized direct, indirect, and total effects of material and psychosocial factors on gingival bleeding at follow-up.

A total of 770 14-year-old adolescents were reassessed (follow-up rate of 68%). The lower SEP at baseline had a higher direct effect (standard coefficient [SC] = -0.17, P < 0.01) than a mediated effect on percentage of teeth with gingival bleeding at 2-year follow-up. The lower indirect effect (SC = -0.06, P < 0.01) from SEP to gingival bleeding at follow-up ran through biological factors-dental plaque (baseline and follow-up) and gingival bleeding at baseline. The lower religiosity of the parents as a psychosocial aspect had only a small direct effect (SC = -0.10, P = 0.03) on gingival bleeding at follow-up.

Material factors such as SEP contributed most to explanations on inequalities in adolescents' periodontal health because of their higher direct effect and additional shared (indirect) effect (through biological factors) on gingival bleeding. Religious practice as a psychosocial factor only explained part of percentage of teeth with gingival bleeding at follow-up.