1. Two-year neurocognitive responses to first occupational lead exposure
- Author
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Lutgarde Thijs, Nelly D. Saenen, Zhenyu Zhang, Jesus D. Melgarejo, Dong-Mei Wei, Cai-Guo Yu, Gladys E. Maestre, Harry Roels, Tim S. Nawrot, Jan A. Staessen, Wen-Yi Yang, Yu-Ling Yu, Staessen, Jan A./0000-0002-3026-1637, and WEI, DONGMEI/0000-0001-7010-468X
- Subjects
neurocognitive function ,Adult ,Male ,medicine.medical_specialty ,digit-symbol test ,neurocognitive response ,Statistical significance ,Internal medicine ,Occupational Exposure ,lead exposure ,medicine ,Humans ,Effects of sleep deprivation on cognitive performance ,Longitudinal Studies ,Lead (electronics) ,Child ,Stroop test ,business.industry ,Public Health, Environmental and Occupational Health ,Random effects model ,Confidence interval ,Lead ,neurocognitive ,Key terms: digit-symbol test ,Original Article ,Female ,Public aspects of medicine ,RA1-1270 ,Geometric mean ,business ,Neurocognitive ,Stroop effect - Abstract
Objectives Lead exposure causes neurocognitive dysfunction in children, but its association with neurocognition in adults at current occupational exposure levels is uncertain mainly due to the lack of longitudinal studies. In the Study for Promotion of Health in Recycling Lead (NCT02243904), we assessed the two-year responses of neurocognitive function among workers without previous known occupational exposure newly hired at lead recycling plants. Methods Workers completed the digit-symbol test (DST) and Stroop test (ST) at baseline and annual follow-up visits. Blood lead (BL) was measured by inductively coupled plasma mass spectrometry (detection limit 0.5 mu g/dL). Statistical methods included multivariable-adjusted mixed models with participants modelled as random effect. Results DST was administered to 260 participants (11.9% women; 46.9%/45.0% whites/Hispanics; mean age 29.4 years) and ST to 168 participants. Geometric means were 3.97 and 4.13 mu g/dL for baseline BL, and 3.30 and 3.44 for the last-follow-up-to-baseline BL ratio in DST and ST cohorts, respectively. In partially adjusted models, a doubling of the BL ratio was associated with a 0.66% [95% confidence interval (CI) 0.03-1.30%; P=0.040] increase in latency time (DST) and a 0.35% (95% CI -1.63-1.63%; P=0.59) decrease in the inference effect (ST). In fully adjusted models, none of the associations of the changes in the DST and ST test results with the blood lead changes reached statistical significance (P=0.12). Conclusions An over 3-fold increase in blood lead over two years of occupational exposure was not associated with a relevant decline in cognitive performance. The International Lead Association (www.ila-lead.org) provided an unrestricted grant to the Research Unit Hypertension and Cardiovascular Epidemiology, KU Leuven Department of Cardiovascular Sciences, University of Leuven, partially supporting database management and statistical analysis. The non-profit research institute Alliance for the Promotion of Preventive Medicine (www.appremed.org) received a grant from OMRON Healthcare Co. Ltd., Kyoto, Japan. The funding source had no role in the study design; in the collection, analysis, and interpretation of the data; or in the writing of the report. The corresponding author had full access to all data and had the final responsibility for the decision to submit for publication. Staessen, JA (corresponding author), Res Inst Assoc Promot Prevent Med, Leopoldstr 59, BE-2800 Mechelen, Belgium. jan.staessen@appremed.org
- Published
- 2021