Does individual and neighbourhood social capital in early childhood influence oral health-related quality of life?

Design Prospective cohort study with seven years of follow-up. Cohort selection All children aged under six years, who attended one of 15 randomly selected health centres in the municipality of Santa Maria, a city in Southern Brazil on National Children's Vaccination Day in 2010. Exposure measurement Individual social support was measured by a questionnaire which asked parents if they had attended a volunteer group in the previous 12 months and if they participated in any groups related to the child's school. Neighbourhood social capital was measured for each of the 15 neighbourhoods, by indicating the presence or absence of each of the following three types of community assets: social-class associations; workers associations; and cultural community centres. Outcome measurement Oral health-related quality of life (OHRQofL) was assessed using the Brazilian version of the Child Perception Questionnaire, for 8-10-year-olds (CPQ8-10). This includes a 5-point Likert score across 25 questions relating to oral symptoms, functional limitations, emotional well-being, and social well-being. The total mean score for each exposure group was calculated, ranging from 0-100, where higher scores indicate poorer OHRQofL. Data analysis The association between individual and neighbourhood social capital at baseline and oral health-related quality of life at follow-up was assessed using a multi-level Poisson regression model to create incidence-rate-ratios where a ratio greater than 1 indicates poorer OHRQofL. Other variables included in the model were: sex; household income; household crowding; dental attendance behavior; presence of dental caries; and presence of increased maxillary overjet. Results Of the 639 children originally enrolled in the study, 449 children were included at follow up (70.3%). Children who lived in a community that had a social-class association (IRR 0.79, 95% CI 0.67-0.93) or workers association (IRR 0.79, 95% CI 0.78-0.93) at baseline had lower oral health impact scores (better oral health-related quality of life) seven years later. The presence of cultural community centres was not associated with OHRQofL. Parental involvement with school activities at baseline was also associated with better OHRQofL at follow up (IRR 1.23, 95% CI 1.14-1.34), but participation in a voluntary network was not. Other variables that had a significant association with OHRQofL were: sex; household income; household crowding; dental attendance pattern; caries incidence; and increased maxillary overjet.Conclusions Oral health-related quality of life was influenced by individual and neighbourhood social capital.