TY - JOUR T1 - The role of literacy in the association between educational attainment and depressive symptoms JF - SSM - Population Health Y1 - 2017 A1 - Thu T Nguyen A1 - Eric J. Tchetgen Tchetgen A1 - Ichiro Kawachi A1 - Stephen E. Gilman A1 - Stefan Walter A1 - M. Maria Glymour KW - Depressive symptoms KW - Education KW - Literacy AB - There is a consistent association between education and depressive symptoms, but research on the mechanisms to explain this association remains limited. No study has formally evaluated the extent to which the association between education and depressive symptoms is mediated through a foundational skill such as literacy. Inverse odds ratio weighting (IORW) was used to estimate total, natural direct, and natural indirect effects in examining literacy as a mediator of the association between education and depressive symptoms. Health and Retirement Study participants born in the U.S. between 1900 and 1947 were interviewed biennially for up to 12 years (N = 16,718). Literacy was assessed with a brief vocabulary measure. Depressive symptoms were measured using the 8-item Centers for Epidemiologic Studies-Depression (CES-D) scale. Decomposition estimates were derived using regression analyses of repeated measures of depressive symptoms. Standard errors were obtained using a nonparametric bootstrap with the individual as the independent unit to account for dependence of observations within an individual. In a large cohort of older Americans, a one standard deviation difference in educational attainment (~ 3 years) was associated with a 0.35-point decrement in CES-D score (95% CI: -0.38, -0.32). This decrement represents a 0.22 standard deviation difference in depressive symptoms. Using IORW, the estimated effect of education on depressive symptoms mediated through literacy was -0.10 (95% CI: -0.18, -0.01), which represents 28% of the total effect. Education confers many benefits; as demonstrated by this study for depressive symptoms, one important benefit is literacy. VL - 3 UR - http://linkinghub.elsevier.com/retrieve/pii/S2352827316301197http://api.elsevier.com/content/article/PII:S2352827316301197?httpAccept=text/xmlhttp://api.elsevier.com/content/article/PII:S2352827316301197?httpAccept=text/plain JO - SSM - Population Health ER - TY - JOUR T1 - Comparing Alternative Effect Decomposition Methods: The Role of Literacy in Mediating Educational Effects on Mortality. JF - Epidemiology Y1 - 2016 A1 - Thu T Nguyen A1 - Eric J. Tchetgen Tchetgen A1 - Ichiro Kawachi A1 - Stephen E. Gilman A1 - Stefan Walter A1 - M. Maria Glymour KW - Aged KW - Aged, 80 and over KW - Educational Status KW - Female KW - Humans KW - Literacy KW - Longitudinal Studies KW - Male KW - Middle Aged KW - Mortality KW - Odds Ratio KW - Proportional Hazards Models KW - United States AB -

BACKGROUND: Inverse odds ratio weighting, a newly proposed tool to evaluate mediation in exposure-disease associations, may be valuable for a host of research questions, but little is known about its performance in real data. We compare this approach to a more conventional Baron and Kenny type of decomposition on an additive hazards scale to estimate total, direct, and indirect effects using the example of the role of literacy in mediating the effects of education on mortality.

METHODS: Health and Retirement Study participants born in the United States between 1900 and 1947 were interviewed biennially for up to 12 years (N = 17,054). Literacy was measured with a brief vocabulary assessment. Decomposition estimates were derived based on Aalen additive hazards models.

RESULTS: A 1 standard deviation difference in educational attainment (3 years) was associated with 6.7 fewer deaths per 1000 person-years (β = -6.7, 95% confidence interval [CI]: -7.9, -5.4). Of this decrease, 1.3 fewer deaths (β = -1.3, 95% CI: -4.0, 1.2) were attributed to the literacy pathway (natural indirect), representing 19% of the total effect. Baron and Kenny estimates were consistent with inverse odds ratio weighting estimates but were less variable (natural indirect effect: -1.2 [95% CI: -1.7, -0.69], representing 18% of total effect).

CONCLUSION: In a cohort of older Americans, literacy partially mediated the effect of education on mortality. See Video Abstract at http://links.lww.com/EDE/B78.

VL - 27 UR - http://www.ncbi.nlm.nih.gov/pubmed/27280331 IS - 5 U1 - http://www.ncbi.nlm.nih.gov/pubmed/27280331?dopt=Abstract ER -