Microcystins and Daily Sunlight: Predictors of Chronic Liver Disease and Cirrhosis Mortality
Author(s): Rajesh Melaram
Cyanobacteria (blue-green algae) may rapidly propagate under favorable conditions, forming dense blooms. As blooms deteriorate, blue-green algae can generate potent toxins, potentially harmful to companion animals, wildlife, and humans. Microcystin is a widely studied toxin, and ingestion of contaminated drinking water is a frequent route of human exposure. The algae toxin has been detected in global drinking water supplies, particularly in regions plagued by liver disease. Microcystin production is dependent on environmental factors driven by changes in weather, including nutrient levels, pH, and water temperature. No prior study examined the ecological association between microcystins and liver disease mortality, accounting for meteorological factors. The purpose of the ecological study was to determine if meteorological factors and microcystins predicted liver disease mortality rates in the United States. Environmental data (CDC WONDER) and toxin data (USEPA) were used in multiple linear regression analyses. Mean daily sunlight and mean total microcystins significantly predicted age-adjusted chronic liver disease and cirrhosis death rates (p < 0.05). Mean annual precipitation (p = 0.156) and mean daily maximum temperature (p = 0.149) non-significantly predicted age-adjusted chronic liver disease and cirrhosis death rates. The study demonstrated that meteorological factors and concurrent microcystin concentrations might contribute to an increase in liver disease mortality across the United States. The results can prompt others to study environmental exposures of chronic liver diseases, guiding environmental health and the water industry of human survival needs.