Research Project: Lithium in Drinking Water
Lithium in drinking water and prescriptions effects on suicide mortality
Suicides are under the ten most common causes of death. An urban-rural analysis of the past three decades showed that suicide risk in urban regions has more rapidly decreased as compared to rural areas. However, the geographic variation of suicide rates in Austria is still not fully understood.
Geographic analyses of the suicide mortality distribution in Austria employing a hierarchical Bayesian model that accounted for spatially correlated random effects showed that a significant proportion of the variance of regional suicide rates may predominantly be explained by population density - a marker of urbanity -, the mean per capita income of the region, and the religious composition of the population. However, given the existing evidence that lithium, a suicide preventive, naturally contained in usual drinking water from the tap, may have effects on suicide mortality, further analyses of the suicide distribution in Austria were done. Lithium in drinking water remained a significant contributor to the geographic pattern of suicide mortality in simple linear regression models as well as in a Geographically Weighted Regression model. However, to challenge this result, other possible factors have to be considered. There are numerous reports pointing to the public health problem of pharmaceuticals in waste water (e.g. carbamazepine and ibuprofen).
It is possible that the lithium distribution in drinking water is due to prescribed lithium rather than of natural origin only. Lithium is used in medicine since more than 60 years as a mood-stabilizer and suicide preventive and could have accumulated in sediments. If true, the geographic pattern of suicides would be not determined by natural lithium effects but by the geographical pattern of prescription practice, while levels of lithium in drinking water would suggest pollution with medication instead of natural levels. The main hypothesis of this project is that prescription rates of lithium are associated with lithium contents in drinking water.