Methods: Data collected previously at 36 collection sites from 23 countries were available for 3896 patients with bipolar I disorder, born between latitudes of 1.4N and 70.7N, and 1.2S and 41.3S. Hours of daylight variables for the birth location were added to a base model to assess the relation between the age of onset and solar insolation.
Results: More hours of daylight at the birth location during early life was associated with an older age of onset, suggesting reduced vulnerability to the future circadian challenge of the springtime increase in solar insolation at the onset location. Addition of the minimum of the average monthly hours of daylight during the first 3 months of life improved the base model, with a significant positive relationship to age of onset. Coefficients for all other variables remained stable, significant and consistent with the base model.
Conclusions: Light exposure during early life may have important consequences for those who are susceptible to bipolar disorder, especially at latitudes with little natural light in winter. This study indirectly supports the concept that early life exposure to light may affect the long term adaptability to respond to a circadian challenge later in life.
Bibliographical noteNOTICE: this is the author’s version of a work that was accepted for publication in Journal of psychiatric research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Bauer, M., Glenn, T., Alda, M., Andreassen, O. A., Angelopoulos, E., Ardau, R., ... Whybrow, P. C. (2015). Influence of light exposure during early life on the age of onset of bipolar disorder. Journal of psychiatric research, In Press (2015) DOI http://dx.doi.org/10.1016/j.jpsychires.2015.03.013
- bipolar disorder
- hours of daylight
- age of onset