Odor-related Chronic Somatic Symptoms Are Associated with Self-Reported Asthma and Hay Fever: The Hordaland Health Study.

The aetiology behind odor-related chronic somatic symptoms (O-RCSS) is unknown, although both immunological and psychiatric causes have been suggested. The aim of this study was to investigate the occurrence of self-reported asthma and hay fever and psychiatric symptoms in individuals having O-RCSS compared to individuals with similar chronic somatic symptoms (CSS) which were not odors-related, and also compared to healthy controls. Data from the Hordaland Health Study were used. 13,799 individuals, 40-45 years, answered a questionnaire including 16 questions related to somatic symptoms. They also indicated if the symptoms were odor-related, and answered questions about asthma and hay fever. Anxiety and depression were measured with the Hospital Anxiety and Depression Scale. 38 (0.6%) men and 106 (1.4%) women had O-RCSS, whereas 88 (1.5%) men and 192 (2.5%) women had CSS. Adjusted logistic regression analyses showed increased odds of self-reported asthma in those with O-RCSS compared to those with CSS (males: 3.81, 1.06-13.8, females: 2.60, 1.05-6.93) and compared to male and female controls (3.56, 1.89-6.68 and 4.81, 1.92-12.1 respectively). Increased odds of self-reported hay fever were in addition seen in females with O-RCSS. There were no differences in psychiatric symptoms between individuals with O-RCSS and CSS, although individuals in both groups showed increased odds compared to male and female controls. Increased occurrence of self-reported asthma was exclusively found among male and females with O-RCSS, compared to CSS and controls. Increased occurrence of psychiatric symptoms was seen both in individuals with O-RCSS and CSS.