Association between feeling cold in the bedroom and the incidence of upper respiratory infection symptoms

A cold ambient temperature in the house may be associated with risk of respiratory infection. In this study, we aimed to determine if there is a significant association between a perception of a cold bedroom and the presence of upper respiratory infection symptoms in order to inform efforts to reduce the incidence of upper respiratory infections in the study population. For this study, subjects were purposely selected from employees and their spouses of a single company in Kyushu, Japan. The study was conducted from December 2018 to March 2019. Each subject was asked to complete a self-administered questionnaire and which best classified how they felt at bedtime: never, sometimes or always. Each subject was also asked whether they had upper respiratory tract infection symptoms, whether they took over-the-counter medication or saw a physician for their symptoms. Between-group differences were examined for significance using the Chi square test. Logistic regression analysis was used to evaluate the potential association between the level of perceived coldness and the likelihood of having an upper respiratory tract infection and its consequences. A total of 1196 subjects were included in the study, 64% male (826 employees (89% male) and 370 spouses (8% male)). The mean age of study subjects was 44 (±12) years. Of the total subjects, 44%, 44% and 12% never/rarely felt cold at bedtime, sometimes felt cold at bedtime and often/always felt cold at bedtime, respectively. Of the total subjects, 52% had upper respiratory tract infection symptoms. When compared with subjects who never/rarely felt cold, subjects who always/often felt cold had significantly greater odds of having upper respiratory tract infection symptoms (adjusted odds ratio (adjusted OR) = 2.56; 95% confidence interval (CI): 1.33-4.91; p = 0.005), having taken over-the-counter drugs for upper respiratory tract infection symptoms (adjusted OR = 1.90; 95% CI: 1.95-2.91; p = 0.003), having taken sick leave for an upper respiratory tract infection (adjusted OR = 3.54; 95% CI: 1.63-7.69; p = 0.001) and having visited a doctor for upper respiratory tract infection symptoms (adjusted OR = 3.22; 95% CI: 1.18-8.80; p = 0.022). In our study population, feeling cold in the bedroom at nighttime was significantly associated with having upper respiratory tract infection symptoms, visiting a doctor and taking sick leave. A change in the room temperature at nighttime should be considered for those who feel cold at nighttime. Further studies are needed to determine if changing the temperature of the bedroom so the person does not feel cold at nighttime will result in fewer episodes of upper respiratory tract infections or not.