Citation

Qin P, Mortensen PB, Waltoft BL, Postolache TT. Allergy 2011; 66(5): 658-664.

Affiliation

National Centre for Register-based Research, Aarhus University, Aarhus, Denmark Mood and Anxiety Program, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA.

Copyright

(Copyright © 2011, John Wiley and Sons)

DOI

10.1111/j.1398-9995.2010.02523.x

PMID

21143241

Abstract

Background:  With increasing research suggesting a role of allergy on suicidality, this study, on a population level, delved into how allergy affects risk for suicide completion in the context of mood disorder and other factors. Methods:  Based on the entire population of Denmark, we included 27 096 completed suicides and 467 571 live controls matched on sex and age with a nested case-control design. We retrieved personal information on hospital contacts for allergy and other variables from various Danish longitudinal registries and analyzed the data with conditional logistic regression. Results:  We noted that 1.17% suicide victims, compared with 0.79% matched controls, had a history of hospital contact for allergy and that a history of allergy predicted an increased risk for suicide completion; however, the effect was confined to allergy that led to inpatient treatment (IRR: 1.59, 95% CI: 1.41-1.80). The increased risk was attenuated somewhat but remained significant when adjusted for personal psychiatric history and socioeconomic status. Meanwhile, we observed a nonsignificantly stronger effect in women than in men, and a significant age difference with a stronger effect for individuals at high ages. Moreover, we detected a significant interaction between allergy and mood disorder - even an antagonism effect of the two exposures. Allergy increased suicide risk only in persons with no history of mood disorder, whereas it eliminated suicide risk in those with a history of mood disorder. Conclusions:  The findings support a link between allergy and suicidality, with a possible mediating role of mood disorder.

Language: en