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Association between polarity of first episode and solar insolation in bipolar I disorder

Research output: Contribution to journalArticlepeer-review

Allan Young, MIchael Bauer

Original languageEnglish
Article number110982
JournalJournal of Psychosomatic Research
Volume160
Early online date25 Jun 2022
DOIs
E-pub ahead of print25 Jun 2022
PublishedSep 2022

Bibliographical note

Funding Information: 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). Biju Viswanath is supported by the Intermediate (Clinical and Public Health) Fellowship (IA/CPHI/20/1/505266) of the DBT/Wellcome Trust India Alliance. Funding Information: Rasmus W. Licht has received research grants from Glaxo Smith Kline, honoraria for lecturing from Pfizer, Glaxo Smith Kline, Eli Lilly, Astra-Zeneca, Bristol-Myers Squibb, Janssen Cilag, Lundbeck, Otsuka, Servier and honoraria from advisory board activity from Glaxo Smith Kline, Eli Lilly, Astra-Zeneca, Bristol-Myers Squibb, Janssen Cilag, Sunovion and Sage. All other authors report no competing interests. Funding Information: 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 ). Biju Viswanath is supported by the Intermediate (Clinical and Public Health) Fellowship ( IA/CPHI/20/1/505266 ) of the DBT/Wellcome Trust India Alliance . Publisher Copyright: © 2022 Elsevier Inc.

King's Authors

Abstract

Objective: Circadian rhythm disruption is commonly observed in bipolar disorder (BD). Daylight is the most powerful signal to entrain the human circadian clock system. This exploratory study investigated if solar insolation at the onset location was associated with the polarity of the first episode of BD I. Solar insolation is the amount of electromagnetic energy from the Sun striking a surface area of the Earth. Methods: Data from 7488 patients with BD I were collected at 75 sites in 42 countries. The first episode occurred at 591 onset locations in 67 countries at a wide range of latitudes in both hemispheres. Solar insolation values were obtained for every onset location, and the ratio of the minimum mean monthly insolation to the maximum mean monthly insolation was calculated. This ratio is largest near the equator (with little change in solar insolation over the year), and smallest near the poles (where winter insolation is very small compared to summer insolation). This ratio also applies to tropical locations which may have a cloudy wet and clear dry season, rather than winter and summer. Results: The larger the change in solar insolation throughout the year (smaller the ratio between the minimum monthly and maximum monthly values), the greater the likelihood the first episode polarity was depression. Other associated variables were being female and increasing percentage of gross domestic product spent on country health expenditures. (All coefficients: P ≤ 0.001). Conclusion: Increased awareness and research into circadian dysfunction throughout the course of BD is warranted.

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