Income-based life-course models of caries in 30-year-old Australian adults.

Abstract

To assess income-based life-course models between the age of 13 and 30 years and caries in young adults. In 1988-89, n = 7673 South Australian school children aged 13 years were sampled with n = 4604 children (60.0%) and n = 4476 parents (58.3%) returning questionnaires. In 2005-06, n = 632 baseline study participants aged 30 years responded (43.0% of those traced and living in Adelaide). Life-course models representing critical period, cumulative risk and social mobility were constructed using income tertiles at ages 13 and 30 years. Critical period was evaluated by comparing the low tertile with the middle and higher tertiles at age 13. Cumulative risk was evaluated by coding the low tertile as 2, the middle tertile as 1 and highest tertile as 0, and summing to produce a cumulative risk score categorized into lower (score 0-1), moderate (score of 2) and higher risk (scores 3-4). Social mobility was classified using tertiles into stable disadvantaged, downwardly mobile, stable middle income, upwardly mobile and stable advantaged. Models adjusting for sex, visiting and toothbrushing at age 30 showed no association between caries at age 30 and low income at age 13 years (critical period model). Compared to the low cumulative risk group based on income, decayed teeth (RR = 1.6) and missing teeth (RR = 7.2) were higher (P < 0.05) in the higher risk group, and missing teeth (RR = 6.0) were higher in the moderate risk group (cumulative risk model). There were more (P < 0.05) decayed teeth in the disadvantaged (RR = 3.1) and stable middle income groups (RR = 2.2), more missing teeth for those classified as disadvantaged (RR = 6.4), stable middle (RR = 6.3) and downwardly mobile (RR = 2.8), and higher DMFT for the disadvantaged group (RR = 1.5) compared to the upwardly mobile group (social mobility model). Socioeconomic advantage and upward mobility were associated with fewer decayed and missing teeth at age 30 years. Life-course models of cumulative risk and social mobility influenced oral health outcomes across childhood to adulthood.