Retrospective Study
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Diabetes. Mar 15, 2022; 13(3): 251-259
Published online Mar 15, 2022. doi: 10.4239/wjd.v13.i3.251
Hemoglobin within normal range is negatively related to hemoglobin A1c in a nondiabetic American population aged 16 years and older
Xiao-Fang Bai, Huan Wang, Qiao-Ling Zhao
Xiao-Fang Bai, Qiao-Ling Zhao, Department of Ultrasound Medicine, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an 710061, Shannxi Province, China
Huan Wang, Department of Pain Medicine, The First Affiliated Hospital, Xi'an Jiao tong University, Xi'an 710061, Shannxi Province, China
Author contributions: Bai XF sorted out the data and wrote the draft; Wang H and Zhao QL revised the article.
Conflict-of-interest statement: The authors declare that they have no competing interests.
Data sharing statement: The data that support the findings of this study are openly available by contacting the corresponding author.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Qiao-Ling Zhao, MD, PhD, Professor, Department of Ultrasound Medicine, The First Affiliated Hospital, Xi'an Jiaotong University, No. 277 Yanta West Road, Xi'an 710061, Shaanxi Province, China. imagingzhaoql@126.com
Received: September 19, 2021
Peer-review started: September 19, 2021
First decision: November 8, 2021
Revised: December 6, 2021
Accepted: February 20, 2022
Article in press: February 20, 2022
Published online: March 15, 2022
Abstract
BACKGROUND

Protein glycosylated hemoglobin, hemoglobin A1c (HbA1c) binds hemoglobin (Hb) in red blood cells to blood glucose. However, the relationship between Hb and HbA1c remains unclear.

AIM

To elucidate their relationship in a nondiabetic population aged ≥ 16 years in the United States, using data from the 1999-2018 National Health and Nutrition Examination Survey.

METHODS

This study was based on data from 44560 adults aged ≥ 16 years, excluding those with diabetes. The relationship was estimated using a multivariate regression. We also used piecewise linear regression for subgroup analysis based on age and sex stratification and analysis of the threshold effects of Hb on HbA1c.

RESULTS

Hb and HbA1c levels were negatively correlated in the unadjusted model (β = -0.01; 95%CI: -0.01, -0.01). The correlation was significantly negative when the regression model was minimally regulated and stratified by age and sex, and remained negative when the model was further regulated (more than 10%) to identify covariates with the HbA1c level influence estimates. In subgroup analyses based on age and sex stratification, the association remained negative when the covariates were controlled. A nonlinear relationship was observed between them when the Hb levels reached the tipping point (13.2 g/dL) (adjusted odds ratio, -0.04; 95%CI: -0.05, -0.03) and when the Hb levels exceeded 13.2 g/dL (adjusted odds ratio, -0.10; 95%CI: -0.10, -0.09).

CONCLUSION

Our study shows that normal Hb levels are negatively correlated with HbA1c in nondiabetic Americans aged ≥ 16 years.

Keywords: Haemoglobin, Glycosylated haemoglobin, Diabetes, National Health and Nutrition Examination Survey

Core Tip: Our research revealed that hemoglobin (Hb) within the normal values is negatively related to hemoglobin A1c (HbA1c) in non-diabetic American populations aged 16 years and older. HbA1c decreases by 0.08% for every 1g/dL increase in Hb.