SPHERL: Study for Promotion of Health in Recycling Lead

Sponsor

KU Leuven (Other)

Overall Status

Active, not recruiting

CT.gov ID

NCT02243904

Collaborator

(none)

270

Enrollment

Location

113

Duration (Months)

2.4

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

Study for Promotion of Health in Recycling Lead (SPHERL) is a prospective 2-year follow-up study of lead workers with exposure levels varying between and within individuals. SPHERL addresses to what extent between-subject differences or within-subject changes in lead exposure may have a measurable impact on blood pressure, the cardiovascular system, renal function, the autonomic nervous system, peripheral nervous conduction velocity, and neurocognitive function.

At the beginning of December 2015, 70 participants were included in the study.

Condition or Disease	Intervention/Treatment	Phase
Occupational Exposure

Detailed Description

Background

Whether low-level lead exposure impacts on blood pressure, regulation of the cardiovascular system, glomerular or tubular renal function, sympathetic nervous modulation, peripheral nervous conduction velocity, and neurocognitive function remains uncertain.

Study Population

SPHERL will enroll 500 lead recycling workers with changing lead exposure, who will be examined at baseline (2014-2015) and followed up at annual intervals for 2 years (2016-2017).

Methods

Volunteers eligible for the study are (i) new and existing hires without previous occupational lead exposure who will be performing tasks with or without occupational lead exposure and (ii) existing hires with occupational lead exposure who will be transitioning to job tasks without occupational lead exposure within the next 2 years.
Blood lead concentration will be the main biomarker of exposure.
The main outcome variables are (i) blood pressure measured conventionally and by ambulatory monitoring, and analyzed as continuous or categorical variable, both cross-sectionally and longitudinally; (ii) indexes of glomerular and tubular renal function, (iii) heart rate variability analyzed in the frequency domain as measure of autonomous sympathetic modulation, (iv) peripheral nerve conductivity, (v) neurocognitive performance, (vi) and quality of life [the EuroQOL five dimensions (EQ-5D) questionnaire].

Expected Outcomes

Assuming a 4-fold or higher surge in the blood lead concentration, the study is powered to demonstrate over 2 years an acceleration in the age-related rise of systolic blood pressure by 1 to 4 mm Hg or an increase of the coefficient of multiple determination (R2) from 0.22 to 0.24 by adding the change in the blood lead concentration to models relating changes in blood pressure to three other covariables. The longitudinal design of our study complies with the temporality principle of the Bradford-Hill criteria for assessing possible causality between outcomes and exposure.

Study Design

Study Type:

Observational

Actual Enrollment :

270 participants

Observational Model:

Cohort

Time Perspective:

Prospective

Official Title:

Study for Promotion of Health in Recycling Lead

Study Start Date :

Aug 1, 2015

Anticipated Primary Completion Date :

Jul 1, 2024

Anticipated Study Completion Date :

Dec 31, 2024

Arms and Interventions

Arm	Intervention/Treatment
Lead exposure

Outcome Measures

Primary Outcome Measures

Annual change in systolic blood pressure as measured by 24-h ambulatory monitoring [Baseline, 1 year and 2 years]

Secondary Outcome Measures

Annual change in central hemodynamics [Baseline, 1 year and 2 years]
Annual changes in the central hemodynamics, including aortic blood pressure, the central systolic augmentation index, and aortic pulse wave velocity
Annual change in heart function [Baseline, 1 year and 2 years]
Annual changes in ECG-derived indexes
Annual change in renal function [Baseline, 1 year and 2 years]
Annual changes in glomerular and tubular renal function measured on a continuous scale and the incidence of renal dysfunction
Annual change in autonomic nervous function [Baseline, 1 year and 2 years]
Annual changes in alterations in the autonomic nervous cardiovascular modulation, as assessed by heart rate variability
Annual change in peripheral nervous conduction velocity [Baseline, 1 year and 2 years]
Annual changes in nerve conduction velocity
Annual change in neurocognitive performance [Baseline, 1 year and 2 years]
Annual changes in neurocognitive testing
Annual change in quality of life [Baseline, 1 year and 2 years]
Annual changes in self-assessed quality of life

Eligibility Criteria

Criteria

Ages Eligible for Study:

N/A and Older

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Inclusion Criteria:

Women and men are eligible.
New hires without previous occupational lead exposure who will be performing tasks with lead exposure or current employees without previous occupational lead exposure moving to tasks with exposure.
Informed written consent.