TY - JOUR
T1 - Variations in seasonal solar insolation are associated with a history of suicide attempts in bipolar I disorder
AU - Bipolar Disorder - collaborative project
AU - Bauer, Michael
AU - Glenn, Tasha
AU - Achtyes, Eric D.
AU - Alda, Martin
AU - Agaoglu, Esen
AU - Altınbaş, Kürşat
AU - Andreassen, Ole A.
AU - Angelopoulos, Elias
AU - Ardau, Raffaella
AU - Vares, Edgar Arrua
AU - Aydin, Memduha
AU - Ayhan, Yavuz
AU - Baethge, Christopher
AU - Bauer, Rita
AU - Baune, Bernhard T.
AU - Balaban, Ceylan
AU - Becerra-Palars, Claudia
AU - Behere, Aniruddh P.
AU - Behere, Prakash B.
AU - Belete, Habte
AU - Belete, Tilahun
AU - Belizario, Gabriel Okawa
AU - Bellivier, Frank
AU - Belmaker, Robert H.
AU - Benedetti, Francesco
AU - Berk, Michael
AU - Bersudsky, Yuly
AU - Bicakci, Şule
AU - Birabwa-Oketcho, Harriet
AU - Bjella, Thomas D.
AU - Brady, Conan
AU - Cabrera, Jorge
AU - Cappucciati, Marco
AU - Castro, Angela Marianne Paredes
AU - Chen, Wei Ling
AU - Cheung, Eric Y.Wo
AU - Chiesa, Silvia
AU - Crowe, Marie
AU - Cuomo, Alessandro
AU - Dallaspezia, Sara
AU - Del Zompo, Maria
AU - Desai, Pratikkumar
AU - Dodd, Seetal
AU - Donix, Markus
AU - Etain, Bruno
AU - Fagiolini, Andrea
AU - Fellendorf, Frederike T.
AU - Ferensztajn-Rochowiak, Ewa
AU - Fiedorowicz, Jess G.
AU - Osher, Yamima
N1 - Funding Information:
Open Access funding enabled and organized by Projekt DEAL. Michael Berk is supported by a NHMRC Senior Principal Research Fellowship (1156072). Pierre A. Geoffroy, Chantal Henry and Josselin Houenou received grants from the French Agence Nationale pour la Recherche (ANR-11-IDEX-0004 Labex BioPsy “Olfaction and Bipolar Disorder” collaborative project, ANR-10-COHO-10–01 psyCOH and ANR-DFG ANR-14-CE35–0035 FUNDO). Mok Yee Ming, Mythily Subramaniam, and Wen Lin Teh received funding from the National Medical Research Centre (NMRC) Centre Grant (Ref No: NMRC/CG/M002/2017_IMH).
Publisher Copyright:
© 2021, The Author(s).
PY - 2021/12/1
Y1 - 2021/12/1
N2 - Background: Bipolar disorder is associated with circadian disruption and a high risk of suicidal behavior. In a previous exploratory study of patients with bipolar I disorder, we found that a history of suicide attempts was associated with differences between winter and summer levels of solar insolation. The purpose of this study was to confirm this finding using international data from 42% more collection sites and 25% more countries. Methods: Data analyzed were from 71 prior and new collection sites in 40 countries at a wide range of latitudes. The analysis included 4876 patients with bipolar I disorder, 45% more data than previously analyzed. Of the patients, 1496 (30.7%) had a history of suicide attempt. Solar insolation data, the amount of the sun’s electromagnetic energy striking the surface of the earth, was obtained for each onset location (479 locations in 64 countries). Results: This analysis confirmed the results of the exploratory study with the same best model and slightly better statistical significance. There was a significant inverse association between a history of suicide attempts and the ratio of mean winter insolation to mean summer insolation (mean winter insolation/mean summer insolation). This ratio is largest near the equator which has little change in solar insolation over the year, and smallest near the poles where the winter insolation is very small compared to the summer insolation. Other variables in the model associated with an increased risk of suicide attempts were a history of alcohol or substance abuse, female gender, and younger birth cohort. The winter/summer insolation ratio was also replaced with the ratio of minimum mean monthly insolation to the maximum mean monthly insolation to accommodate insolation patterns in the tropics, and nearly identical results were found. All estimated coefficients were significant at p < 0.01. Conclusion: A large change in solar insolation, both between winter and summer and between the minimum and maximum monthly values, may increase the risk of suicide attempts in bipolar I disorder. With frequent circadian rhythm dysfunction and suicidal behavior in bipolar disorder, greater understanding of the optimal roles of daylight and electric lighting in circadian entrainment is needed.
AB - Background: Bipolar disorder is associated with circadian disruption and a high risk of suicidal behavior. In a previous exploratory study of patients with bipolar I disorder, we found that a history of suicide attempts was associated with differences between winter and summer levels of solar insolation. The purpose of this study was to confirm this finding using international data from 42% more collection sites and 25% more countries. Methods: Data analyzed were from 71 prior and new collection sites in 40 countries at a wide range of latitudes. The analysis included 4876 patients with bipolar I disorder, 45% more data than previously analyzed. Of the patients, 1496 (30.7%) had a history of suicide attempt. Solar insolation data, the amount of the sun’s electromagnetic energy striking the surface of the earth, was obtained for each onset location (479 locations in 64 countries). Results: This analysis confirmed the results of the exploratory study with the same best model and slightly better statistical significance. There was a significant inverse association between a history of suicide attempts and the ratio of mean winter insolation to mean summer insolation (mean winter insolation/mean summer insolation). This ratio is largest near the equator which has little change in solar insolation over the year, and smallest near the poles where the winter insolation is very small compared to the summer insolation. Other variables in the model associated with an increased risk of suicide attempts were a history of alcohol or substance abuse, female gender, and younger birth cohort. The winter/summer insolation ratio was also replaced with the ratio of minimum mean monthly insolation to the maximum mean monthly insolation to accommodate insolation patterns in the tropics, and nearly identical results were found. All estimated coefficients were significant at p < 0.01. Conclusion: A large change in solar insolation, both between winter and summer and between the minimum and maximum monthly values, may increase the risk of suicide attempts in bipolar I disorder. With frequent circadian rhythm dysfunction and suicidal behavior in bipolar disorder, greater understanding of the optimal roles of daylight and electric lighting in circadian entrainment is needed.
KW - Bipolar disorder
KW - Circadian
KW - Psychiatry
KW - Seasonal variation
KW - Solar insolation
KW - Suicide
KW - Sunlight
UR - http://www.scopus.com/inward/record.url?scp=85114003020&partnerID=8YFLogxK
U2 - 10.1186/s40345-021-00231-7
DO - 10.1186/s40345-021-00231-7
M3 - Article
C2 - 34467430
AN - SCOPUS:85114003020
SN - 2194-7511
VL - 9
JO - International Journal of Bipolar Disorders
JF - International Journal of Bipolar Disorders
IS - 1
M1 - 26
ER -