# The association of manganese levels with red cell distribution width: A population-based study

## TL;DR

This study finds a J-shaped relationship between blood manganese levels and red blood cell distribution width in the U.S. population.

## Contribution

The study is the first to explore the association between environmental manganese exposure and RDW in a general population.

## Key findings

- Blood manganese levels were positively associated with RDW (β = 0.079, P<0.001).
- A J-shaped relationship was observed with an inflection point at 7.32 ug/L blood manganese.
- Women showed a more pronounced association compared to other subgroups.

## Abstract

Experimental and acute exposure studies imply that manganese affects red blood cell production. Nevertheless, the association between environmental exposure and red blood cell distribution width (RDW) has yet to be explored. This research sought to assess the correlation between blood manganese levels and RDW within the general population of the United States.

Employing weighted multiple linear regression models, data from the 2011–2018 National Health and Nutrition Examination Survey (NHANES) were utilized to assess the correlation between manganese levels in the blood and RDW. Restricted cubic spline plots and two-piecewise linear regression models were also employed.

The analysis included a total of 15882 participants in which we determined an independent positive relationship between blood manganese levels and RDW among participants(β = 0.079, P<0.001). Moreover, we identified a J-shaped association between blood manganese levels and RDW in total participants (inflection point for blood manganese: 7.32 ug/L) and distinct subgroups following adjusted covariates. Women exhibited a more pronounced association, even after controlling for adjusted covariates.

We determined a J-shaped relationship between blood manganese levels and RDW with an inflection point at 7.32 ug/L for blood manganese. Nevertheless, fundamental research and large sample prospective studies are needed to determine the extent to which blood manganese levels correlate with RDW.