# Assessing the impact of 25-hydroxyvitamin concentrations on mortality in chronic diarrhea: a cross-sectional analysis

## TL;DR

This study found that higher vitamin D levels are linked to lower mortality in people with chronic diarrhea, but only up to a certain threshold.

## Contribution

The study identifies a specific threshold for 25-hydroxyvitamin D levels associated with reduced mortality in chronic diarrhea patients.

## Key findings

- An L-shaped relationship was observed between 25-hydroxyvitamin D and all-cause mortality with a threshold of 73.40 nmol/L.
- Each 1-unit increase in vitamin D below the threshold reduced mortality risk by 2.2%.
- No significant correlation was found above the 73.40 nmol/L threshold.

## Abstract

The aim of this study was to assess the relationship between serum 25-hydroxyvitamin levels and all-cause mortality in patients with chronic diarrhea.

We carried out a cross-sectional study using information drawn from the National Health and Nutrition Examination Survey (NHANES). To assess mortality outcomes, we compared our data with records from the National Death Index as of December 31, 2011. The NHANES data were used to determine mortality outcome. We used a Cox regression model-based approach to analyze the relationship between serum 25-hydroxyvitamin concentrations and mortality in chronic diarrhea patients.

A total of 2,972 participants with chronic diarrhea were included in our study, 488 cases of all-cause mortality were recorded. The study showed an L-shaped relationship between 25-hydroxyvitamin concentrations and all-cause mortality with a threshold of 73.40 nmol/L. On the left side of the threshold, each 1-unit increase in 25-hydroxyvitamin concentrations was associated with a 2.2% reduction in the risk of all-cause mortality (HR 0.978; 95% CI: 0.969, 0.987); however, on the right side of the threshold, there was no significant correlation between 25(OH)D concentrations and all-cause mortality.

Serum 25-hydroxyvitamin D levels showed an L-shaped association with all-cause mortality in patients with chronic diarrhea, with 73.40 nmol/L as the potential threshold. However, because this was a cross-sectional study, only an association, not a causal relationship, can be inferred. Further prospective studies are needed to confirm these findings and explore the potential impact of vitamin D supplementation on mortality outcomes.