Cold-related respiratory symptoms in the general population.

INTRODUCTION

Cold-related respiratory symptoms are common among northern populations, especially among people suffering from respiratory diseases. However, the prevalence of such symptoms in the general population and the threshold temperatures at which the symptoms start to emerge are poorly known.

OBJECTIVES

The present study determined the prevalence and threshold temperatures of self-reported respiratory symptoms related to cold, separately for healthy people and those with respiratory disease.

MATERIALS AND METHODS

Six thousand five hundred ninety-one men and women aged 25 years-74 years from the national FINRISK study were queried about cold-related respiratory symptoms. The results were expressed as age-adjusted prevalence figures and coefficients from multivariate regressions.

RESULTS

Cold-related respiratory symptoms were more often reported by people with asthma (men 69%/women 78%) and by subjects with chronic bronchitis (65%/76%) than the healthy subjects (18%/21%). A binomial regression showed an increase of symptom prevalence by age and excesses of 4%, 50% and 21% units because of female sex, asthma and chronic bronchitis, respectively. The reported threshold temperature for cold-related symptoms was -14 degrees C for males and -15 degrees C for females, and it showed some increase by age (0 degrees C-5 degrees C), asthma (2 degrees C) and chronic bronchitis (3 degrees C). The threshold temperature for mucus production was exceptional as it decreased by age (2 degrees C-5 degrees C) and asthma (2 degrees C). The effects of smoking and education were marginal.

CONCLUSION

Cold-related respiratory symptoms are common in patients with chronic respiratory diseases, but they start to emerge at relatively low temperatures. In a cold climate, the cold-related symptoms may have an impact on the health-related quality of life.