Use of anthropogenic nitrogen fertilizers in agriculture is associated with per capita ethanol consumption

Abstract

It has previously been demonstrated that emissions of the agricultural pollutant, nitrous oxide (N2O), may be a confounder to the relationship between herbicide use and psychiatric impairments, including ADHD. This report attempts to extend this hypothesis by testing whether annual use of anthropogenic nitrogen-based fertilizers in U.S. agriculture (thought to be the most reliable indicator of environmental N2O emissions) is associated with per capita ethanol consumption patterns, a behavior often comorbid with ADHD. State estimates of anthropogenic nitrogen fertilizers from the United States Geological Survey (USGS) were obtained for the years between 1987 and 2006. Our dependent variable was annual per capita ethanol consumption. Ethanol consumption was categorized as beer, wine, spirits, and all alcoholic beverages. Least squares dummy variable method using two-ways fixed effects was utilized. Among states above the 50th percentile in farm use of anthropogenic nitrogen for all years (i.e., agricultural states), a one log-unit increase in farm use of anthropogenic nitrogen fertilizers is associated with a 0.13 gallon increase in total per capita ethanol consumption (p<0.0125). No statistically significant association between farm use of anthropogenic nitrogen and per capita ethanol consumption was found in states below the 50th percentile in farm use of anthropogenic nitrogen. The new findings are in agreement with both behavioral human studies demonstrating a link between N2O preference and alcohol and drug use history as well as molecular studies elucidating shared mechanisms between trace N2O antinociception and alcohol-seeking related behaviors.