The Influence of Family Income Trajectories From Birth to Adulthood on Adult Oral Health: Findings From the 1982 Pelotas Birth Cohort

摘要

Objectives. We assessed whether 3 models of life course socioeconomic status (critical period, accumulation of risk, and social mobility) predicted unsound teeth in adulthood among a Brazilian cohort. Methods. Life course data were collected on the 5914 live-born infants in the 1982 Pelotas Birth Cohort study. Participants' oral health was assessed at 15 (n = 888) and 24 (n = 720) years of age. We assessed family income trajectories and number of episodes of poverty in the life course through Poisson regressions, yielding unadjusted and adjusted prevalence ratios for number of unsound teeth at age 24 years. Results. The adjusted prevalence ratio for participants born into poverty was 30% higher than for those who were not. Participants who were always poor had the highest prevalence of unsound teeth; those who were downwardly or upwardly mobile also had more unsound teeth than did other participants, after adjustment for confounders. More episodes of poverty were associated with greater prevalence of unsound teeth in adulthood. Conclusions. Poverty at birth and during the life course was correlated with the number of unsound teeth at 24 years of age. The relationship between adults' socioeconomic position and their health is well known. However, the majority of studies addressing this issue have used measurements of adulthood socioeconomic position or relied on adults' retrospective reports about their childhood. 1 Adult health may be affected by socioeconomic position during different periods in the life course, and at least 3 major theories have been proposed to explain how and when life course socioeconomic factors influence adult health. One theory proposes that during a critical period of development in early life, exposures to deprivation have long-term effects on adult health, independent of adult circumstances. 2 Galobardes et al. updated a systematic review of the association between childhood socioeconomic conditions and cause-specific mortality; they confirmed that mortality risk for all causes was higher among those who experienced poorer socioeconomic status (SES) during childhood, although not all causes of death were equally related to childhood socioeconomic circumstances. 3 Others theorize that the intensity and duration of exposure to unfavorable or favorable physical and social environments throughout life affect health status in a dose–response relationship; this has been termed the accumulation-of-risk hypothesis. 4 For example, the number of episodes of being in the manual social class (a cumulative harmful exposure) measured at 3 life stages was strongly and positively associated with mortality from cardiovascular disease among Scottish men. 5 A third theory, the social mobility hypothesis, postulates that the importance of the early life environment lies in its effect on the socioeconomic trajectories of individuals. Circumstances in early life are identified as the first step in the pathway to adult health, but with an indirect effect, influencing adult health through social mechanisms such as restricting educational opportunities, thus shaping socioeconomic circumstances and health in later life. 6 In a New Zealander birth cohort, Poulton et al. investigated the association between socioeconomic trajectories during the life course and aspects of health in adulthood; they found that upward mobility did not mitigate or reverse the adverse effects of low childhood SES on adult health. 1 Globally, the burden of common oral conditions is high: one of the most common chronic diseases worldwide is dental caries, severe periodontitis affects between 5% and 15% of most populations, and oral cancer is the eighth most common cancer worldwide. 7 This evidence led the World Health Assembly to call for oral health to be integrated into chronic disease prevention programs. 8 Despite substantial evidence showing that SES is strongly associated with oral health, 9 , 10 the dynamics of how SES over time affects adults' oral health remain unclear. We assessed whether 3 hypotheses about life course SES (critical period, accumulation of risk, and social mobility) predicted an important oral health outcome in early adulthood.