Study for Promotion of Health in Recycling Lead (SPHERL)

March 1, 2020 updated by: Jan A. Staessen, KU Leuven

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.

Study Overview

Status

Active, not recruiting

Conditions

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 Type

Observational

Enrollment (Actual)

270

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Belgium
      • Leuven, Belgium
        • University of Leuven

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Participants will be recruited among the work force employed at lead recycling plants in North America.

Description

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.

Exclusion Criteria:

  • Pregnancy.
  • Any serious health condition.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Cohort
  • Time Perspectives: Prospective

Cohorts and Interventions

Group / Cohort
Lead exposure

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Annual change in systolic blood pressure as measured by 24-h ambulatory monitoring
Time Frame: Baseline, 1 year and 2 years
Baseline, 1 year and 2 years

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Annual change in central hemodynamics
Time Frame: 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
Baseline, 1 year and 2 years
Annual change in heart function
Time Frame: Baseline, 1 year and 2 years
Annual changes in ECG-derived indexes
Baseline, 1 year and 2 years
Annual change in renal function
Time Frame: 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
Baseline, 1 year and 2 years
Annual change in autonomic nervous function
Time Frame: Baseline, 1 year and 2 years
Annual changes in alterations in the autonomic nervous cardiovascular modulation, as assessed by heart rate variability
Baseline, 1 year and 2 years
Annual change in peripheral nervous conduction velocity
Time Frame: Baseline, 1 year and 2 years
Annual changes in nerve conduction velocity
Baseline, 1 year and 2 years
Annual change in neurocognitive performance
Time Frame: Baseline, 1 year and 2 years
Annual changes in neurocognitive testing
Baseline, 1 year and 2 years
Annual change in quality of life
Time Frame: Baseline, 1 year and 2 years
Annual changes in self-assessed quality of life
Baseline, 1 year and 2 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

KU Leuven

Investigators

  • Principal Investigator: Jan A Staessen, MD, PhD, University of Leuven

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

August 1, 2015

Primary Completion (Anticipated)

July 1, 2024

Study Completion (Anticipated)

December 31, 2024

Study Registration Dates

First Submitted

September 10, 2014

First Submitted That Met QC Criteria

September 16, 2014

First Posted (Estimate)

September 18, 2014

Study Record Updates

Last Update Posted (Actual)

March 3, 2020

Last Update Submitted That Met QC Criteria

March 1, 2020

Last Verified

March 1, 2020

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • SPHERL

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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