Lithium in drinking water and incidence of suicide: A nationwide individual-level cohort study with 22 years of follow-up

TY - JOUR

T1 - Lithium in drinking water and incidence of suicide

T2 - A nationwide individual-level cohort study with 22 years of follow-up

AU - Knudsen, Nikoline N.

AU - Schullehner, Jörg

AU - Hansen, Birgitte

AU - Jørgensen, Lisbeth F.

AU - Kristiansen, Søren M.

AU - Voutchkova, Denitza D.

AU - Gerds, Thomas A.

AU - Andersen, Per K.

AU - Bihrmann, Kristine

AU - Grønbæk, Morten

AU - Kessing, Lars V.

AU - Ersbøll, Annette K.

PY - 2017/6/10

Y1 - 2017/6/10

N2 - Suicide is a major public health concern. High-dose lithium is used to stabilize mood and prevent suicide in patients with affective disorders. Lithium occurs naturally in drinking water worldwide in much lower doses, but with large geographical variation. Several studies conducted at an aggregate level have suggested an association between lithium in drinking water and a reduced risk of suicide; however, a causal relation is uncertain. Individual-level register-based data on the entire Danish adult population (3.7 million individuals) from 1991 to 2012 were linked with a moving five-year time-weighted average (TWA) lithium exposure level from drinking water hypothesizing an inverse relationship. The mean lithium level was 11.6 µg/L ranging from 0.6 to 30.7 µg/L. The suicide rate decreased from 29.7 per 100,000 person-years at risk in 1991 to 18.4 per 100,000 person-years in 2012. We found no significant indication of an association between increasing five-year TWA lithium exposure level and decreasing suicide rate. The comprehensiveness of using individual-level data and spatial analyses with 22 years of follow-up makes a pronounced contribution to previous findings. Our findings demonstrate that there does not seem to be a protective effect of exposure to lithium on the incidence of suicide with levels below 31 µg/L in drinking water.

AB - Suicide is a major public health concern. High-dose lithium is used to stabilize mood and prevent suicide in patients with affective disorders. Lithium occurs naturally in drinking water worldwide in much lower doses, but with large geographical variation. Several studies conducted at an aggregate level have suggested an association between lithium in drinking water and a reduced risk of suicide; however, a causal relation is uncertain. Individual-level register-based data on the entire Danish adult population (3.7 million individuals) from 1991 to 2012 were linked with a moving five-year time-weighted average (TWA) lithium exposure level from drinking water hypothesizing an inverse relationship. The mean lithium level was 11.6 µg/L ranging from 0.6 to 30.7 µg/L. The suicide rate decreased from 29.7 per 100,000 person-years at risk in 1991 to 18.4 per 100,000 person-years in 2012. We found no significant indication of an association between increasing five-year TWA lithium exposure level and decreasing suicide rate. The comprehensiveness of using individual-level data and spatial analyses with 22 years of follow-up makes a pronounced contribution to previous findings. Our findings demonstrate that there does not seem to be a protective effect of exposure to lithium on the incidence of suicide with levels below 31 µg/L in drinking water.

KW - Denmark

KW - Drinking water

KW - Exposure assessment

KW - Individual-level data

KW - Lithium

KW - Spatial analysis

KW - Suicide

UR - http://www.scopus.com/inward/record.url?scp=85020768130&partnerID=8YFLogxK

U2 - 10.3390/ijerph14060627

DO - 10.3390/ijerph14060627

M3 - Journal article

C2 - 28604590

AN - SCOPUS:85020768130

SN - 1661-7827

VL - 14

SP - 1

EP - 13

JO - International Journal of Environmental Research and Public Health

JF - International Journal of Environmental Research and Public Health

IS - 6

M1 - 627

ER -