Relationship between freshwater harmful algal blooms and neurodegenerative disease incidence rates in South Korea

• Published in: Environmental health Vol. 21; no. 1; pp. 116 - 11
• Main Authors: Lee, Seungjun, Choi, Boseung, Kim, Sung Jae, Kim, Jinnam, Kang, Dayun, Lee, Jiyoung
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 26.11.2022; BioMed Central; BMC
• Subjects: Aerosol; Algae; Algal blooms; Alzheimer's disease; Amyotrophic lateral sclerosis; Anthropogenic factors; Aquatic ecosystems; BMAA; Chlorophyll; Climate change; Cross-Sectional Studies; Cyanobacteria; Degeneration; Drinking water; Environmental aspects; Environmental health; Epidemiology; Eutrophication; Fresh Water; Global warming; Gridded population; Harmful Algal Bloom; Health aspects; Health risk assessment; Health risks; Human influences; Humans; Incidence; Information systems; Liver cancer; Mathematical models; Metabolites; Microcystin; Motor neuron diseases; Movement disorders; Nervous system; Neurodegenerative diseases; Neurodegenerative Diseases - chemically induced; Neurodegenerative Diseases - epidemiology; Neurotoxicity; Neurotoxins; Parkinson Disease - epidemiology; Parkinson's disease; Population (statistical); Population number; Shellfish; Statistical analysis; Statistical models; Time series; Toxins; Water bloom; Water quality; South Korea; United States > US; Microcystin; Alzheimer’s disease; BMAA; Aerosol; Gridded population; Parkinson’s disease
• ISSN: 1476-069X; 1476-069X
• DOI: 10.1186/s12940-022-00935-y

Due to anthropogenic activities and global warming, the severity and distribution of harmful algal blooms (HABs) have been increasing steadily worldwide, including in South Korea (S. Korea). Previous studies reported that exposure to HABs could increase the risk of HAB-related diseases. However, very few studies examined the linkage between HABs and disease occurrence, particularly in S. Korea. The objective of this study was to evaluate the potential impact of HABs on neurodegenerative diseases (NDs), including Alzheimer's disease, Parkinson's disease, and motor neuron disease, at a population level. Thirteen-year data (2005-2017) for chlorophyll-a (chl-a) concentrations as a bloom-related parameter, annual numbers of NDs, and population information were collected. First, the entire area of S. Korea was divided into a grid of 1 km, and the population number in each 1-km grid was collected using the Statistical Geographic Information Service Plus system. Cross-sectional time series data were analyzed with two statistical models, a generalized linear mixed model and a generalized linear model. The results show a general trend of increasing chl-a concentration and NDs year by year. We observed positive correlations between HAB intensity and the incidence rate of NDs. Particularly, HABs seem to have the most long-term carry-over effect on Parkinson's disease. Another key finding was that a 5-km radius from the HAB location was the boundary that showed the most significant associations with three NDs. This study provides statistical evidence that supports the potential risk of NDs from the exposure to HAB. Thus, it is recommended to monitor a broad spectrum of cyanotoxins, including neurotoxins, in bloom-affected regions in S. Korea and epidemiological studies in the future.