Table 1

Proposed explanations for differences in HbA1c by race and the weight of evidence supporting those explanations

Factors proposed to explain differenceWeight of evidenceReferences
Age, sex, education, incomeWeak2,3,4
BMI and/or insulin secretion/insulin sensitivityWeak2,3,5
Fasting or postprandial glucose levelsWeak2,3,21
Diet and/or physical activityWeak4,6
Dietary fatModerate7
Alcohol consumptionModerate8
SmokingStrong9
Insurance, access to care, quantity or quality of careWeak4,5
Antihyperglycemic therapy, treatment intensification, medication adherenceWeak4,5
Diabetes distress, self-efficacy, depressionWeak4
SNPs related to red blood cell biologyStrong10,11
SNPs related to hemoglobinModerate12
SNPs related to hemoglobin deglycationModerate11,13,14