Psychological factors such as anxiety and depression are prevalent in patients with asthma. The purpose of this study was to investigate the relationship between respiratory symptoms and psychological status and to estimate the importance of psychological status in comparison with other factors that are known to be associated with respiratory symptoms. This study included 2270 subjects aged 20-44 (52% female) from Sweden, Iceland, and Norway. Each participant underwent a clinical interview including questions on respiratory symptoms. Spirometry and methacholine challenge were performed. Symptoms of depression and anxiety were measured using the Hospital Anxiety and Depression Scale (HADS). Eighty-two percent of the subjects reported no anxiety or depression whatsoever, 11% reported anxiety, 2.5% depression and 4% reported both anxiety and depression. All respiratory symptoms, such as wheezing, breathlessness and nightly symptoms, were more common, at a statistically significant level, in participants who had depression and anxiety, even after adjusting for confounders (ORs 1.33-1.94). The HADS score was the most important determinant for nightly symptoms and attacks of breathlessness when at rest whereas bronchial responsiveness was the most important determinant for wheezing, and breathlessness when wheezing. The probability of respiratory symptoms related to HADS score increased with increasing HADS score for all respiratory symptoms. In conclusion, there is a strong association between respiratory symptoms and psychological status. There is therefore a need for interventional studies designed to improve depression and anxiety in patients with respiratory symptoms.

The causes of the worldwide increase in asthma seen during the last decades remain largely unexplained, but lifestyle and diet are suggested to play important roles. In this follow up of a large-scale population sample in Sweden, we wanted to identify modifiable risk factors for the cumulative incidence over a 13-year follow-up period. In 1990, a self-administered questionnaire was completed by 12,560 individuals from three age groups (16, 30-39 and 60-69 years of age) in two counties of Sweden. In 2003, the eligible subjects (n = 11,282) were sent a new postal questionnaire. In total 8150 (response rate 73%) answered the questionnaire. The prevalence of asthma in 2003 had increased in all ages. In the young adults, the asthma prevalence rose from 11.3% in 1990 to 25.0% in 2003. Adult asthma onset was identified in 791 of the participants. Smoking [RR (95% CI) = 1.37 (1.12-1.68)], BMI [1.49 (1.25-1.77 per inter quartile range)], and nocturnal gastro-oesophageal reflux (GOR) [2.16 (1.72-2.72)] were significant independent risk factors for the cumulative incidence of asthma. The impact of risk factors differed between the age groups where BMI and GOR had a significantly higher impact in the middle aged and the elderly (p < 0.05). High consumption of fruit and fish was protective especially in the elderly [0.52 (0.35-0.77)]. No significant difference was found in the impact of risk factors between men and women. Weight loss, smoking cessation and a diet rich in fruit and fish may be of importance in preventing onset of adult asthma.

Participants with low health-related quality of life at baseline were more likely to report having developed asthma 12 years later.

The physical score was significantly lower in asthmatics compared to subjects without asthma. Importantly, non-smoking and well-controlled asthmatics have similar HRQL compared to subjects without asthma. Thus, subjects with asthma should be supported to achieve and maintain good asthma control and if they smoke, be offered smoking cessation as means to improve their HRQL.