Association between hemoglobin A1c and abdominal aortic calcification: results from the National Health and Nutrition Examination Survey 2013-2014

Abstract

Background: Hemoglobin A1c (HbA1c), a "gold standard" for the assessment of glycemic control, was associated with an increased risk of cardiovascular disease and coronary artery calcification. However, its effects on abdominal aortic calcification (AAC) are uncertain. The present study comprehensively investigated the association between HbA1c and AAC in the 2013-2014 National Health and Nutrition Examinations Surveys.

Methods: Among 1,799 participants ≥ 40 years, dual-energy X-ray absorptiometry-derived AAC was quantified using the Kauppila score (AAC-24). Severe AAC was defined as a total AAC-24 > 6. Weighted linear regression models and logistic regression models were used to determine the effects of HbA1c on AAC. The restricted cubic spline model was used for the dose-response analysis.

Results: The mean AAC-24 of participants was 1.3, and 6.7% of them suffered from severe AAC. Both AAC-24 and the prevalence of severe AAC increased with the higher tertile of HbA1c (P < 0.001). Elevated HbA1c levels would increase the AAC-24 (β = 0.73, 95% CI: 0.30-1.16) and the risk of severe AAC (OR = 1.63, 95% CI: 1.29-2.06), resulting in nearly linear dose-response relationships in all participants. However, this positive correlation were not statistically significant when participants with diabetes were excluded. Furthermore, subgroup analysis showed significant interactions effect between HbA1c and hypertension on severe AAC with the OR (95% CI) of 2.35 (1.62-3.40) for normotensives and 1.39 (1.09-1.79) for hypertensives (P for interaction = 0.022).

Conclusion: Controlling HbA1c could reduce AAC scores and the risk of severe AAC. Glycemic management might be a component of strategies for preventing AAC among all participants, especially normotensives.

Keywords: Abdominal aortic calcification; Cross-sectional study; Hemoglobin A1c; NHANES.

Fig. 1

Flowchart of participant selection NHANES, National Health and Nutrition Examination Survey; AAC, abdominal aortic calcification, HbA1c, hemoglobin A1c

Fig. 2

Subgroup analysis for the association between HbA1c level as a continuous variable and severe AAC. Odds ratio adjusted for variables in the Model 3 (age, gender, BMI, race, education level, RIP, smoking status, alcohol drinking status, metabolic equivalent, SBP, TC, eGFR, total 25-hydroxyvitamin D, serum calcium, serum phosphorus, and NLR) except the corresponding stratification variable OR: odds ratio; CI, confidence interval; BMI, body mass index; HbA1c, hemoglobin A1c

Fig. 3

Dose-response relation between hemoglobin A1c level and AAC. a, Dose-response relation between hemoglobin A1c level and AAC-24 score; b, Dose-response relation between hemoglobin A1c level and severe AAC. The restricted cubic spline model was adjusted by age, gender, BMI, race, education level, RIP, smoking status, alcohol drinking status, metabolic equivalent, SBP, TC, eGFR, total 25-hydroxyvitamin D, serum calcium, serum phosphorus, and NLR. AAC, abdominal aortic calcification, HbA1c, hemoglobin A1c