More schooling is associated with lower hemoglobin A1c at the high-risk tail of the distribution: an unconditional quantile regression analysis

Abstract Background Risk of diabetes increases exponentially with higher levels of glycosylated hemoglobin (HbA1c). Education is inversely associated with average HbA1c, however, differential associations between education and HbA1c across the HbA1c distribution have not been evaluated. Methods Heal...

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Main Authors: Jillian Hebert, Amanda M. Irish, Aayush Khadka, Abigail Arons, Alicia R. Riley, Elbert S. Huang, Anusha M. Vable
Format: Article
Language:English
Published: BMC 2025-06-01
Series:BMC Public Health
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Online Access:https://doi.org/10.1186/s12889-025-23063-x
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author Jillian Hebert
Amanda M. Irish
Aayush Khadka
Abigail Arons
Alicia R. Riley
Elbert S. Huang
Anusha M. Vable
author_facet Jillian Hebert
Amanda M. Irish
Aayush Khadka
Abigail Arons
Alicia R. Riley
Elbert S. Huang
Anusha M. Vable
author_sort Jillian Hebert
collection DOAJ
description Abstract Background Risk of diabetes increases exponentially with higher levels of glycosylated hemoglobin (HbA1c). Education is inversely associated with average HbA1c, however, differential associations between education and HbA1c across the HbA1c distribution have not been evaluated. Methods Health and Retirement Study data (N = 21,732) was used to evaluate the association between education (linear terms among those with < 12 years and ≥ 12 years of education) and first recorded HbA1c (2003–2016) at the mean using linear regression, and at the 1st-99th quantiles of the marginal outcome distribution using unconditional quantile regressions, controlling for birth year, race and ethnicity, gender, birthplace, parental education, and year of HbA1c measurement. Results Mean HbA1c was 5.9%; 16.6% of participants had HbA1c above the diabetes diagnostic threshold of 6.5%. For those with fewer than 12 years of schooling, there was no association between education and HbA1c at the mean or across the quantiles. For those with 12 or more years of schooling, an additional year of education was negatively associated with mean HbA1c (βOLS=-0.02, 95% confidence interval (CI) -0.03,-0.02); a one-year increase in mean education was associated with lower HbA1c across the distribution, but the magnitude was larger at higher quantiles (βq50=-0.02, 95%CI -0.02,-0.01; βq90=-0.06, 95%CI -0.09,-0.04). Conclusions Educational attainment is inversely associated with HbA1c among those with 12 or more years of schooling, with larger point estimates for those in the high-risk tail of the HbA1c distribution.
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spelling doaj-art-eacc4989dfc9427d8995daf084269c9e2025-08-20T03:26:43ZengBMCBMC Public Health1471-24582025-06-0125111110.1186/s12889-025-23063-xMore schooling is associated with lower hemoglobin A1c at the high-risk tail of the distribution: an unconditional quantile regression analysisJillian Hebert0Amanda M. Irish1Aayush Khadka2Abigail Arons3Alicia R. Riley4Elbert S. Huang5Anusha M. Vable6Department of Family and Community Medicine, University of CaliforniaDepartment of Family and Community Medicine, University of CaliforniaDepartment of Family and Community Medicine, University of CaliforniaDepartments of Internal Medicine and Pediatrics, University of California, San FranciscoDepartment of Sociology, University of California, Santa CruzDepartments of Medicine and Public Health Sciences, University of ChicagoDepartment of Family and Community Medicine, University of CaliforniaAbstract Background Risk of diabetes increases exponentially with higher levels of glycosylated hemoglobin (HbA1c). Education is inversely associated with average HbA1c, however, differential associations between education and HbA1c across the HbA1c distribution have not been evaluated. Methods Health and Retirement Study data (N = 21,732) was used to evaluate the association between education (linear terms among those with < 12 years and ≥ 12 years of education) and first recorded HbA1c (2003–2016) at the mean using linear regression, and at the 1st-99th quantiles of the marginal outcome distribution using unconditional quantile regressions, controlling for birth year, race and ethnicity, gender, birthplace, parental education, and year of HbA1c measurement. Results Mean HbA1c was 5.9%; 16.6% of participants had HbA1c above the diabetes diagnostic threshold of 6.5%. For those with fewer than 12 years of schooling, there was no association between education and HbA1c at the mean or across the quantiles. For those with 12 or more years of schooling, an additional year of education was negatively associated with mean HbA1c (βOLS=-0.02, 95% confidence interval (CI) -0.03,-0.02); a one-year increase in mean education was associated with lower HbA1c across the distribution, but the magnitude was larger at higher quantiles (βq50=-0.02, 95%CI -0.02,-0.01; βq90=-0.06, 95%CI -0.09,-0.04). Conclusions Educational attainment is inversely associated with HbA1c among those with 12 or more years of schooling, with larger point estimates for those in the high-risk tail of the HbA1c distribution.https://doi.org/10.1186/s12889-025-23063-xUnconditional quantile regressionDistributional effectsEffect heterogeneityDiabetesUS Health and Retirement Study (HRS)
spellingShingle Jillian Hebert
Amanda M. Irish
Aayush Khadka
Abigail Arons
Alicia R. Riley
Elbert S. Huang
Anusha M. Vable
More schooling is associated with lower hemoglobin A1c at the high-risk tail of the distribution: an unconditional quantile regression analysis
BMC Public Health
Unconditional quantile regression
Distributional effects
Effect heterogeneity
Diabetes
US Health and Retirement Study (HRS)
title More schooling is associated with lower hemoglobin A1c at the high-risk tail of the distribution: an unconditional quantile regression analysis
title_full More schooling is associated with lower hemoglobin A1c at the high-risk tail of the distribution: an unconditional quantile regression analysis
title_fullStr More schooling is associated with lower hemoglobin A1c at the high-risk tail of the distribution: an unconditional quantile regression analysis
title_full_unstemmed More schooling is associated with lower hemoglobin A1c at the high-risk tail of the distribution: an unconditional quantile regression analysis
title_short More schooling is associated with lower hemoglobin A1c at the high-risk tail of the distribution: an unconditional quantile regression analysis
title_sort more schooling is associated with lower hemoglobin a1c at the high risk tail of the distribution an unconditional quantile regression analysis
topic Unconditional quantile regression
Distributional effects
Effect heterogeneity
Diabetes
US Health and Retirement Study (HRS)
url https://doi.org/10.1186/s12889-025-23063-x
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