# The association between whole-blood lead concentration and all-cause or cardiovascular disease mortality in hypertensive patients

## TL;DR

Higher blood lead levels are linked to increased mortality risk in people with high blood pressure, according to a study of over 8,000 U.S. adults.

## Contribution

This study reveals a non-linear positive correlation between blood lead concentration and mortality in hypertensive patients.

## Key findings

- Higher whole-blood lead levels correlated with increased all-cause and cardiovascular mortality in hypertensive patients.
- The risk of all-cause mortality rose significantly in the highest blood lead quartile compared to the lowest.
- Kaplan-Meier curves showed reduced survival with higher blood lead levels in hypertensive individuals.

## Abstract

The purpose of this study was to examine the relationship between whole-blood lead levels and mortality in a hypertensive population in the United States. In our study, 8364 subjects aged 20 years and older were included. We used a weighted COX proportional risk regression model to calculate risk ratios (HR) and 95% confidence intervals (CI) for blood lead and mortality. The relationship between whole-blood lead levels and mortality was described by a restricted cubic spline curve. Kaplan Meier curves were used to describe the relationship between survival time and survival in study subjects, and all-cause mortality was analyzed in subgroups. Using the lowest quartile (Q1) as a reference, the HRs for all-cause mortality in model 3 (Q2, Q3, and Q4) were 1.05 (95% CI 0.84–1.32), 1.10 (95% CI 0.89–1.36), and 1.44 (95% CI 1.16–1.79), respectively. For cardiovascular mortality, they were 1.03 (95% CI 0.62–1.52), 1.30 (95% CI 0.77–2.21), and 1.97 (95% CI 1.31–2.97), respectively. Weighted restricted cubic spline regression confirmed a positive correlation between whole-blood lead levels and risk ratio (HR) (P-overall < 0.001). Weighted Kaplan–Meier curves showed a significant downward trend in survival in the hypertensive population with increasing whole-blood lead levels. (P < 0.0001 for all log-rankings). Subgroup analysis of all-cause mortality showed a strong positive association between whole-blood lead levels and all-cause mortality in different populations. Whole-blood lead concentration showed a non-linear positive correlation with all-cause mortality and cardiovascular mortality in hypertensive patients.

The online version contains supplementary material available at 10.1038/s41598-025-22009-y.