Trends in tooth loss in relation to socio-economic status among Swedish women, aged 38 and 50 years: repeated cross-sectional surveys 1968-2004

Background: Oral diseases are a health problem worldwide. Differences in oral health status may vary with geographical locations, but also within the same country and between groups with different social backgrounds. The specific aims were to describe secular trends in oral health status regarding number of remaining teeth and also to describe differences in socio-economic status, among 38- and 50-year-old women, over a 36-year period. Methods: Cross-sectional health surveys were performed at four occasions; 1968/69 (n = 746), 1980/81 (n = 532), 1992/93 (n = 165) and 2004/05 (n = 500), including randomly selected women aged 38 and 50 years. The number of teeth was determined using panoramic radiographs and self-reported measures of marital status, social class, educational level, and income were recorded. Results: The mean number of teeth among women has increased significantly. The educational level has increased while fewer women are married/cohabiting over time. There has been a shift in the social group the women belong to, where proportionally more women were categorized in a higher social group in 2004/05 than in 1968/69. Moreover, there is a significant relationship between fewer teeth and a lower social group, and among the 50-year-old women, this was irrespective of examination year. However, multivariate analyses showed that the risk to be edentulous or not, or to have fewer remaining teeth was significantly higher for women of lower social group, or living alone, in all studies over the 36 year-period. This was independent of age group, even though the risk diminished over the study period. Conclusions: Cohort comparisons of women aged 38 and 50 years during 36 years showed that dental status improved, with (i) a decreasing prevalence of edentulism and, (ii) an increasing number of remaining teeth in dentate individuals over time. Differences due to social group and education were still present, with more remaining teeth in the women in the higher social group. A time trend analysis indicated that in the later examination years the individuals had fewer teeth lost, irrespective of age, marital status and, social group.