Occupational Noise – Cardiac Hypertension Index (ON-CHI) Calculator

Occupational Noise – Cardiac Hypertension Index (ON-CHI): Explanation and Clinical Context The ON-CHI is a conceptual tool that estimates the incremental hypertensive risk attributable to occupational noise exposure through a simple “risk-points” model integrating ambient noise level (LAeq,8h in dB(A)) and cumulative exposure duration (years). Chronic exposure to elevated occupational noise triggers sympathetic nervous system activation, endocrine stress responses, and vascular resistance increases — all mediators of arterial hypertension. In the occupational-medicine literature, each 1 dB(A) increase in noise exposure was associated with approximately an 8.3% higher odds of hypertension (OR 1.083; 95% CI: 1.058-1.109) in a Chinese automobile-manufacturing cohort.

A large-scale occupational study found workers exposed to noise had an adjusted odds ratio of hypertension ≈ 1.50 (95% CI 1.42-1.58) compared with non-exposed peers. These data provide empirical grounding for the hypothesis that occupational noise contributes additively to blood-pressure elevation and hypertension risk. The estimated adjusted SBP and DBP in this tool reflect the predicted elevation attributable to the calculated risk points.

The “Risk Category” helps stratify workers by their additional noise-related hypertensive burden. Clinical Interpretation Summary: For a worker exposed to higher noise levels for prolonged years, an elevated risk category (“Moderate” or “High”) suggests the need for enhanced surveillance (e.g., periodic BP monitoring), occupational-health interventions (noise-control engineering, personal protective equipment, job rotation) and cardiovascular risk mitigation (lifestyle modification, earlier BP-screening). The tool is not a substitute for formal risk calculators (e.g., for 10-year cardiovascular risk) but acts as an adjunct occupational-cardiology alert.