Relationship between sunlight and the age of onset of bipolar disorder: an international multisite study

J Affect Disord. 2014 Oct;167:104-11. doi: 10.1016/j.jad.2014.05.032. Epub 2014 May 29.
Relationship between sunlight and the age of onset of bipolar disorder: an international multisite study.

Bauer M1, Glenn T2, Alda M3, Andreassen OA4, Angelopoulos E5, Ardau R6, Baethge C7, Bauer R8, Bellivier F9, Belmaker RH10, Berk M11, Bjella TD4, Bossini L12, Bersudsky Y10, Cheung EY13, Conell J8, Del Zompo M14, Dodd S15, Etain B16, Fagiolini A12, Frye MA17, Fountoulakis KN18, Garneau-Fournier J19, González-Pinto A20, Harima H21, Hassel S22, Henry C16, Iacovides A18, Isometsä ET23, Kapczinski F24, Kliwicki S25, König B26, Krogh R27, Kunz M24, Lafer B28, Larsen ER27, Lewitzka U8, Lopez-Jaramillo C29, MacQueen G22, Manchia M3, Marsh W30, Martinez-Cengotitabengoa M20, Melle I4, Monteith S31, Morken G32, Munoz R33, Nery FG28, O’Donovan C3, Osher Y10, Pfennig A8, Quiroz D34, Ramesar R35, Rasgon N19, Reif A36, Ritter P8, Rybakowski JK25, Sagduyu K37, Scippa ÂM38, Severus E8, Simhandl C26, Stein DJ39, Strejilevich S40, Sulaiman AH41, Suominen K42, Tagata H21, Tatebayashi Y43, Torrent C44, Vieta E44, Viswanath B45, Wanchoo MJ17, Zetin M46, Whybrow PC47.
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Abstract

BACKGROUND:

The onset of bipolar disorder is influenced by the interaction of genetic and environmental factors. We previously found that a large increase in sunlight in springtime was associated with a lower age of onset. This study extends this analysis with more collection sites at diverse locations, and includes family history and polarity of first episode.

METHODS:

Data from 4037 patients with bipolar I disorder were collected at 36 collection sites in 23 countries at latitudes spanning 3.2 north (N) to 63.4 N and 38.2 south (S) of the equator. The age of onset of the first episode, onset location, family history of mood disorders, and polarity of first episode were obtained retrospectively, from patient records and/or direct interview. Solar insolation data were obtained for the onset locations.

RESULTS:

There was a large, significant inverse relationship between maximum monthly increase in solar insolation and age of onset, controlling for the country median age and the birth cohort. The effect was reduced by half if there was no family history. The maximum monthly increase in solar insolation occurred in springtime. The effect was one-third smaller for initial episodes of mania than depression. The largest maximum monthly increase in solar insolation occurred in northern latitudes such as Oslo, Norway, and warm and dry areas such as Los Angeles, California.

LIMITATIONS:

Recall bias for onset and family history data.

CONCLUSIONS:

A large springtime increase in sunlight may have an important influence on the onset of bipolar disorder, especially in those with a family history of mood disorders.

Copyright © 2014 Elsevier B.V. All rights reserved.

KEYWORDS:

Age of onset; Bipolar disorder; Insolation; Sunlight