# Association between glycosylated hemoglobin and blood lead: A cross-sectional study

## TL;DR

This study finds a U-shaped relationship between blood lead levels and glycosylated hemoglobin in adults, with differences observed between men and women.

## Contribution

The study reveals a U-shaped association between HbA1c and blood lead, particularly in women, using a large national dataset.

## Key findings

- A negative association between HbA1c and blood lead was observed overall.
- Women showed a U-shaped relationship between HbA1c and blood lead, with a shift at 6.6% HbA1c.
- The association remained statistically significant across subgroups like age, sex, race, and BMI.

## Abstract

Diabetes is the most common chronic metabolic disease, affecting many people's health. Previous studies have shown a close relationship between trace elements and metabolic diseases. This study investigated the interrelationship between glycosylated hemoglobin (HbA1c) and blood lead (BPb) in adults.

This research was carried out involving 12,049 eligible individuals aged 20 years or above from the National Health and Nutrition Examination Survey (NHANES) spanning from 2011 to 2020. Weighted linear regression models and smoothed curve fitting were employed to investigate the association between HbA1c and blood lead. Analyses were stratified based on age, sex, race, and body mass index, and threshold effects were explored using two-stage segmented linear regression models.

Among all 12049 participants, through comprehensive adjustment of the model, this study discovered a negative association between HbA1c and blood lead. In addition, when stratified by sex, age, race, and BMI status in subgroup analysis in this study, this correlation still had specific statistical significance. In performing subgroup analyses, we found that the relationship between HbA1c and blood lead may yield distinct outcomes arise from gender disparities. In women, a significant U-shaped association exists between HbA1c and BPb. At approximately 6.6% of HbA1c value, the relationship between the two shifts from negative to positive.

This investigation proposes a “U” form association between HbA1c and BPb in American adults.