Risk factors of chronic urticaria among nurses with insomnia A nationwide population-based study

Chronic urticaria has a high economic burden and reduces patient's quality of life. Nurses experience insomnia because of their shifting work, especially if they work night shifts and 3-shift rotational schedules. This study aimed to examine whether insomnia is a risk factor of chronic urticaria in nurses. Data were obtained from the Registry for Medical Personnel, which contains all registered medical staff between 2007 and 2008. All study subjects were divided into those with insomnia and without insomnia. The primary exposure of interest was chronic urticaria. In addition, potential comorbidities including diabetes mellitus, hypertension, hyperlipidemia, anxiety, and depression were estimated. A total of 103,242 registered nurses between 2007 and 2008 were enrolled. Around 97,899 (94.8%) nurses did not have insomnia, and 5343 (5.2%) had insomnia. The proportion of chronic urticaria in nurses with insomnia was significantly higher than those without (0.92% vs 0.50%, P < .0001). The odds ratio of chronic urticaria in nurses with insomnia was 1.67 (95% confidence interval: 1.22-2.29, P = 0.0014) compared to those without insomnia after adjusting for age, sex, hospital level, and comorbidities. The risk of chronic urticaria was higher in nurses with insomnia than in those without insomnia. The relationship between insomnia and chronic urticaria might not be a direct causal association. Other contributing factors of insomnia include different perceptions of stress from night shift work, stress coping and adaptation, positive self-image, and emotional equilibrium related to person's capacity to adapt to change. The same situation may have different effects on different individuals.