Dose-dependent relationships between chronic arsenic exposure and cognitive impairment and serum brain-derived neurotrophic factor

Yeasir Karim; Abu Eabrahim Siddique; Faruk Hossen; Mizanur Rahman; Victor Mondal; Hasan Ul Banna; M M Hasibuzzaman; Zubaer Hosen; Md Shofikul Islam; Md Khalequzzaman Sarker; Farjana Nikkon; Zahangir Alam Saud; Lian Xin; Seiichiro Himeno; Khaled Hossain

doi:10.1016/j.envint.2019.105029

Dose-dependent relationships between chronic arsenic exposure and cognitive impairment and serum brain-derived neurotrophic factor

Environ Int. 2019 Oct:131:105029. doi: 10.1016/j.envint.2019.105029. Epub 2019 Jul 25.

Authors

Affiliations

¹ Department of Biochemistry and Molecular Biology, University of Rajshahi, Rajshahi 6205, Bangladesh.
² Department of Applied Nutrition and Food Technology, Islamic University, Kushtia 7003, Bangladesh.
³ Department of Gastroenterology, Rajshahi Medical College, Rajshahi 6000, Bangladesh.
⁴ Laboratory of Molecular Nutrition and Toxicology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima 770-8514, Japan.
⁵ Department of Biochemistry and Molecular Biology, University of Rajshahi, Rajshahi 6205, Bangladesh. Electronic address: khossain@ru.ac.bd.

PMID: 31352261
DOI: 10.1016/j.envint.2019.105029

Abstract

Background: Arsenic poisoning is a public health problem worldwide. A few studies have reported the effects of arsenic exposure on adult cognitive function, but with limitations in the subject selection and exposure markers. Moreover, information regarding the association between arsenic exposure and biomarker of cognitive impairment is scarce.

Objectives: We examined the associations between arsenic exposure and adult cognitive impairment using the Mini-Mental State Examination (MMSE) and the serum levels of brain-derived neurotrophic factor (BDNF), a potential biomarker of cognitive health status.

Methods: We designed a cross-sectional study that recruited 693 adult (18-60 years old) subjects from the areas of low- and high‑arsenic exposure in rural Bangladesh. The subjects' arsenic exposure levels (drinking water, hair, and nail arsenic concentrations) were measured by inductively coupled plasma-mass spectroscopy. The Bangla version of the MMSE was used as a cognitive assessment tool. Serum BDNF (sBDNF) levels were assessed by immunoassay.

Results: In this study, we found that average MMSE score and sBDNF level of the subjects in arsenic-endemic areas were significantly (p < 0.001 for both) lower than those of the subjects in non-endemic area. Our analyses revealed that both MMSE scores and sBDNF levels were decreased with the increasing concentrations of arsenic in drinking water, hair, and nails in a dose-dependent fashion. In regression analyses, significant associations of arsenic exposure metrics with MMSE scores and sBDNF levels were observed even after adjustment for several variables. Intriguingly, MMSE scores showed a significantly positive correlation with sBDNF levels.

Conclusion: Our findings demonstrate that chronic exposure to arsenic dose-dependently decreases cognitive function in adults, with a concomitant reduction of sBDNF levels. A decreased BDNF level may be part of the biochemical basis of chronic arsenic exposure-related cognitive impairment.

Keywords: Arsenic; Bangladesh; Brain-derived neurotrophic factor; Cognitive impairment.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adolescent
Adult
Arsenic / analysis
Arsenic / toxicity*
Bangladesh
Biomarkers / blood
Brain-Derived Neurotrophic Factor / blood*
Cognitive Dysfunction / chemically induced*
Cross-Sectional Studies
Drinking Water / chemistry
Female
Hair / chemistry
Humans
Male
Middle Aged
Nails / chemistry
Water Pollutants, Chemical / analysis
Water Pollutants, Chemical / toxicity*
Young Adult

Substances

Biomarkers
Brain-Derived Neurotrophic Factor
Drinking Water
Water Pollutants, Chemical
BDNF protein, human
Arsenic