Health Disparities
More Schooling is Associated with Lower Hemoglobin A1c (HbA1c) Overall and Especially for High HbA1c Values Among White and Latinx Older Adults, but Not Black Older Adults: A Conditional Quantile Regression Analysis Jillian Hebert* Jillian Hebert Amanda Irish Aayush Khadka Catherine Duarte Abigail Arons Anusha Vable
The relationship between education and hemoglobin A1c (HbA1c) varies by sociodemographic subgroup; however, most studies focus on mean HbA1c. Evaluating the relationship at different points of the HbA1c distribution is critical given links between higher HbA1c, diabetes, and cardiovascular disease mortality. Building on mean-based analyses, we test for race and gender heterogeneity in the relationship between education and HbA1c across the HbA1c distribution.
Data came from 7,327 Health and Retirement Study participants. Our exposure, educational attainment, was defined as number of years in school (5-17 years). Our outcome was first recorded HbA1c value (measured 2003-2016) from dried blood spots. We used conditional quantile regressions (CQR) to evaluate the relationship between educational attainment and HbA1c across the 1st-99th quantiles of the HbA1c distribution stratified by race and gender; all models were adjusted for participant demographics and parents’ education.
The mean HbA1c level in the analytic sample was 5.9% (SD 1.2) with 15% of participants meeting the diagnostic threshold for diabetes (HbA1c > 6.5%). CQR results suggested a one-year increase in educational attainment was associated with lower HbA1c, especially at higher quantiles of the HbA1c distribution for White and Latinx men and women (e.g., White women 20th quantile (q20): b = -0.014, 95%CI(-0.031,0.002); q90: b = -0.069 (-0.116,-0.021)). However, results for Black respondents suggest that a one-year increase in educational attainment was either not associated with HbA1c (e.g., Black women q80: b = 0.002 (-0.074,0.078)), or potentially associated with higher HbA1c (e.g., Black men q80: b = 0.033 (-0.019,0.085)).
Education has a beneficial association on higher values of HbA1c for White and Latinx older adults, but not Black older adults. Further research is needed to understand why Black Americans do not seem to experience the same HbA1c benefits from education that other groups enjoy.
