Air quality was predictably worse near larger cities on both the US East and West Coasts. Water quality was consistent but noted to be worse in the western states, Wyoming and Illinois. Land quality was worse in the northern continental US as well as the west. The central US counties have a greater number of poorer weather days, whereas the coastal areas are enriched with more fair-weather days.
Areas of the country away from large bodies of water are most enriched for neuropsychiatric disorders. This was particularly evident for bipolar disorder and major depression in Kentucky and Missouri. Alaska showed more psychiatric disorders for the overall population size, particularly personality disorders and schizophrenia. Hawaii had higher than expected rates of Parkinson’s disease and schizophrenia. The state of Michigan had a higher rate across all psychiatric disorders, and Parkinson’s disease possibly thought to be due to reporting bias. In general, the US east coast had a greater prevalence of phenotypes compared to the west coast. The strongest predictor of mood disorders (MDD and bipolar disorder) was the percentage of white residents. A higher percentage of black non-Hispanic residents predicted higher schizophrenia and epilepsy. Air quality was the strongest predictor of bipolar disorder. Regions with worse air quality had a 27% increase in bipolar disorder. There was a six percent increase in the diagnosis rate of MDD. Personality disorder was best predicted by land pollution leading to a 19.2% increase in the diagnosis of personality disorders.
Pleasant weather was protective for all disorders, particularly bipolar disorder. Counties with the highest number of pleasant weather days showed a 21.8 % decrease in the diagnosis of bipolar disorder.
The Danish sample was structured differently, comprising individuals born between January 1, 1979, and December 31st, 2002, who were residing in Denmark on their 10th birthday. Childhood air pollution and association of psychiatric disorders (MDD, Bipolar disorder, Personality disorder, and schizophrenia). The rates of all four psychiatric disorders increased with air pollution.The rate increase in the highest exposure to the lowest exposure group was bipolar disorder (29.4%), schizophrenia (148%), personality disorder (162%), and MDD (50.5%), which is alarming.