# Association between comprehensive exposure to multiple occupational hazardous factors and telomere length with hypertension in male steel workers: a case-control study

## TL;DR

This study finds that male steel workers exposed to more occupational hazards have higher hypertension risk, partly explained by shorter telomere length.

## Contribution

The study introduces a new method to assess combined occupational hazards and shows telomere length partially mediates hypertension risk in steel workers.

## Key findings

- Higher occupational hazard scores are strongly linked to increased hypertension risk in steel workers.
- Shorter relative telomere length is independently associated with higher hypertension risk.
- Telomere length partially mediates the relationship between occupational hazards and hypertension.

## Abstract

Steel workers are often exposed to various occupational hazards over the long term, which may be associated with hypertension. Previous studies mainly focused on the relationship between single occupational hazard and hypertension, but the comprehensive effects of multiple occupational hazards and the potential regulation of telomere length are still unclear. This study aims to investigate the relationship between combined exposure to multiple occupational hazards and hypertension in male steel workers, and to assess whether relative telomere length (RTL) plays a mediating role in this relationship.

A 1:1 matched case-control study was conducted, with cases and controls matched on similar age (±2 years). The study included 350 hypertensive male steel workers and 350 normotensive controls. Occupational hazards [including heat, noise, dust, carbon monoxide (CO), shift work, and occupational stress] and relative telomere length (RTL) were assessed. An occupational hazardous factors score (OHFS) was constructed using the XGBoost model and SHapley Additive exPlanations (SHAP). Conditional logistic regression and quantile regression were used to analyze the associations. Mediation analysis was performed to evaluate the potential mediating effect of RTL in the relationship between OHFS and hypertension.

The risk of hypertension among male steel workers in the higher OHFS groups (24.74~, 38.98~, and ≥56.58) was 1.81, 2.17, and 3.46 times higher than that in the lower OHFS group (< 24.74), respectively (24.74~: OR = 1.81, 95% CI: 1.14–2.86; 38.98~: OR = 2.17, 95% CI: 1.39–3.39; ≥56.58: OR = 3.46, 95% CI: 2.18–5.49). The risk of hypertension among male steel workers in the shorter RTL group was 1.45 times higher than that in the longer RTL group (OR = 1.45, 95% CI: 1.04–2.03). A significant multiplicative interaction was observed between OHFS and RTL on hypertension (P < 0.001). Mediation analysis showed a partial mediating effect of RTL on the association between OHFS and hypertension (proportion mediated: 16.67%).

Among male steel workers, higher OHFS is associated with an increased risk of hypertension, and RTL plays a partial mediating role in the relationship between OHFS and hypertension.