Dissolved Lithium Concentrations and

Texas Suicide Mortality Rates 1980-1998

by William M Flanagan

University of North Texas

Department of Geography

Introduction

Spatial distribution of suicide mortality rates in Texas counties, from 1980 – 1998.

Disease ecology conceptual framework.

Suicide Statistics

In US, 32,000 suicide deaths annually.

11th leading causes of death in US.

Texans ranked 37th in completed suicides in 2002 in US.

Risk Predictors of Suicide Mortality

Gender

• Females 3x more likely than males to attempt suicide.

• Males complete suicide 4x more than females.

Risk Predictors of Suicide Mortality

Race

• White males have highest suicide mortality rate.

• Minority females have the lowest.

Risk Predictors of Suicide Mortality

Lithium • Used in treating manic depressive illness

• Suicide, homicide, and forcible rape

• Continued lithium treatment is associated with reduced suicide risk

• Dissolved lithium concentrations in groundwater may provide a protective function on suicide behavior and mortality.

Lithium Concentrations in Nature

Associated with volcanism, may explain presence in many aquifers

Many counties and cities in Texas rely on groundwater for their water needs.

Nutritional uptake of lithium through common foods and vegetables.

Hypotheses

Gender is a predictor of suicide mortality.

Race is a predictor of suicide mortality.

County suicide mortality rates will be influenced by dissolved lithium concentrations in the groundwater.

Suicide mortality rates are changing through time.

Data Sources

Age adjusted mortality data (1980 – 1998) Texas Department of Health’s Vital Statistics Division.

Population and other data from the 2000 US Census.

Dissolved lithium concentration data from Texas Water Development Board Groundwater Database

Methodology

Spearman’s 2-tailed Rank Correlation

Wilcoxon Two Sample Test

GENDER AND SUICIDE

Males have a higher suicide rate than females (Z=-13.706, p=.000).

Males Average = 22.5 per 100,000

Females Average = 5.4 per 100,000

RACE AND SUICIDE

Counties with higher % whites had higher suicide mortality (r=.315, p=.000).

Counties with higher % Hispanics have lower suicide mortality

(r= -.250, p=.000).

No correlation between % African Americans and suicide mortality rates

(r= -.014, p=.827).

LITHIUM CONCENTRATIONS AND SUICIDE

Dissolved lithium concentrations in groundwater is inversely related to suicide mortality rates (r= -.150, p=.017).

TEMPORAL VARIATIONS OF SUICIDE

Suicide mortality rates (1980-1989) are lower than 1990-1998

(Z = -2.351, p=.019).

CONCLUSIONS

Male suicide rates are significantly higher than female suicide mortality rates

% Whites is positively correlation to suicide mortality rates % Hispanics account for a negative correlation to suicide

mortality rates. Counties with lower rates of dissolved lithium

concentrations in groundwater have higher suicide rates Suicide mortality rates are increasing with time.

SUGGESTIONS FOR FURTHER RESEARCH

Intra-county variations ignored

Other water sources (e.g surface and tap water) must be addressed.

Finer geographical scale required.

How the underlying geology affects lithium concentrations.

References

1) Bronisch T et al. 2005. A multicenter study about Neurobiology of Suicidal Behavior: design, development, and preliminary results. Arch Suicide Res. 9(1):19-26.

2) Cipriani A. et al. 2005 Oct. Lithium in the prevention of suicidal behavior and all-cause mortality in patients with mood disorders: a systematic review of randomized trials. Am J Psychiatry. 162(10):1805-19.

3) Dawson EB. The relationship of tap water and physiological levels of lithium to mental hospital admission and homicide in Texas. In Schrauzer GN, KlippelKF (eds): " Lithium in Biology and Medicine." Weinheim: VCH Verlag, pp 171–187, 1991.

4) Dawson EB, Moore TD, McGanity WJ. The mathematical relationship of drinking water lithium and rainfall on mental hospital admission. Dis Nerv Syst 31: 1–10.

5) Dumais A. et al. 2005 Nov. Risk factors for suicide completion in major depression: a case-control study of impulsive and aggressive behaviors in men. Am J Psychiatry. 162(11):2116-24.

6) Henderson JP, Mellin C, Patel F. 2005. Suicide - A statistical analysis by age, sex and method. J Clin Forensic Med. 12(6):305-9.

7) Kaslow NJ et al. 2005 Aug. Social risk and protective factors for suicide attempts in low income African American men and women. Suicide Life Threat Behav. 2005 Aug;35(4):400-12.

References (cont.)

8) Kessing LV et al. 2005 Aug. Suicide risk in patients treated with lithium. Arch Gen Psychiatry. (8):860-6.

9) Moscicki EK. 1997 Sep. Identification of suicide risk factors using epidemiologic studies. Psychiatr Clin North Am 20(3):499-517.

10) Muller-Oerlinghausen B et al. 2005. The impact of lithium long-term medication on suicidal behavior and mortality of bipolar patients. Arch Suicide Res. 9(3):307-19.

11) Schrauzer GN, Shrestha KP. 1990. Lithium in drinking water and the incidences of crimes, suicides, and arrests related to drug addictions. Biol Trace El Res 25: 105–113.

12) Scharuzer GN. Lithium. 2002. Occurrence, Dietary Intakes, Nutritional Essentiality. Journal of the American College of Nutrition. Vol. 21, No. 1, 14-21

13) Stack S, Wasserman I. 2005. Race and method of suicide: culture and opportunity. Arch Suicide Res. 9(1):57-68.

14) Suicide and Crisis Center. Suicide Facts and Statistics. Available at: <http://www.sccenter.org/facts.html>. Accessed October 21, 2005.

15) Texas Water Development Board. Updated Water-Quality Evaluation of the Ogallala Aquifer Including Selected Metallic and Non-Metallic Inorganic Constituents. Available at: <http://www.twdb.state.tx.us/publications/reports/GroundWaterReports/HydrologicAtlases/HA-10.pdf.> Accessed October 21, 2005.