Clinical trial NCT02243904: Study for Promotion of Health in Recycling Lead
Official title: Study for Promotion of Health in Recycling Lead
Study type: OBSERVATIONAL
Overall status: UNKNOWN
Conditions: Occupational Exposure
Keywords: Autonomic nervous function
Blood pressure
Cardiovascular regulation
Lead
Occupational exposure
Renal function
Lead sponsor: KU Leuven
Sponsor class: OTHER
First posted: 2014-09-18
Enrollment: 270
Sex: ALL
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Participants will be recruited among the work force employed at lead recycling plants in North America.

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.

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.

Eligibility criteria: 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.

Primary outcomes:
measure: Annual change in systolic blood pressure as measured by 24-h ambulatory monitoring
timeFrame: Baseline, 1 year and 2 years
Secondary outcomes:
measure: Annual change in central hemodynamics
timeFrame: Baseline, 1 year and 2 years
measure: Annual change in heart function
timeFrame: Baseline, 1 year and 2 years
measure: Annual change in renal function
timeFrame: Baseline, 1 year and 2 years
measure: Annual change in autonomic nervous function
timeFrame: Baseline, 1 year and 2 years
measure: Annual change in peripheral nervous conduction velocity
timeFrame: Baseline, 1 year and 2 years
measure: Annual change in neurocognitive performance
timeFrame: Baseline, 1 year and 2 years
measure: Annual change in quality of life
timeFrame: Baseline, 1 year and 2 years
Other outcomes:
Locations:
city: Leuven
country: Belgium
facility: University of Leuven
Study officials:
affiliation: University of Leuven
name: Jan A Staessen, MD, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Hara A, Gu YM, Petit T, Liu YP, Jacobs L, Zhang ZY, Yang WY, Jin Y, Thijs L, Wei FF, Nawrot TS, Staessen JA. Study for Promotion of Health in Recycling Lead - Rationale and design. Blood Press. 2015 Jun;24(3):147-57. doi: 10.3109/08037051.2014.996409. Epub 2015 Jan 26.
citation: Yu YL, Thijs L, Saenen N, Melgarejo JD, Wei DM, Yang WY, Yu CG, Roels HA, Nawrot TS, Maestre GE, Staessen JA, Zhang ZY. Two-year neurocognitive responses to first occupational lead exposure. Scand J Work Environ Health. 2021 Apr 1;47(3):233-243. doi: 10.5271/sjweh.3940. Epub 2020 Dec 4.
citation: Yu YL, Yang WY, Thijs L, Melgarejo JD, Yu CG, Wei DM, Wei FF, Nawrot TS, Zhang ZY, Staessen JA. Two-Year Responses of Office and Ambulatory Blood Pressure to First Occupational Lead Exposure. Hypertension. 2020 Oct;76(4):1299-1307. doi: 10.1161/HYPERTENSIONAHA.120.15590. Epub 2020 Sep 9.
citation: Yu CG, Wei FF, Yang WY, Zhang ZY, Mujaj B, Thijs L, Feng YM, Staessen JA. Heart rate variability and peripheral nerve conduction velocity in relation to blood lead in newly hired lead workers. Occup Environ Med. 2019 Jun;76(6):382-388. doi: 10.1136/oemed-2018-105379. Epub 2019 Mar 30.