The prevalence and risk factors of hoarseness among pupils in elementary schools in the South of Finland.

Hoarseness and voice problems are one of the chronic conditions experienced by children. The aim of this study was to investigate the prevalence of hoarseness, possible risk factors and effects of the remediation of school buildings to the prevalence of hoarseness among school children. The material was gathered from all the schools in a large city in the south of Finland and the collection method used was an e-mail survey sent to the parents of the pupils and a simultaneous survey sent to the personnel in the schools. All 51 schools participated, and 5889 pupils returned the questionnaire (39%). The exposure data was obtained from two building experts who knew the repair history of the schools. A subjective estimation of the quality of the indoor air was obtained from teachers and the parents. The overall prevalence of hoarseness among pupils was 6.3%; prevalence being higher in unrepaired school buildings than in schools in a good condition or buildings with a thorough remediation. Hoarseness was associated with asthma and allergies, several respiratory symptoms, and respiratory infections. Exposure to tobacco smoke increased the risk, and consumption of caffeine containing drinks seemed to reduce the risk. Noise, stuffiness of the indoor air and microbial smells correlated strongly with the occurrence of hoarseness in a logistic regression model when controlled for age, gender, asthma, passive smoking, and caffeine consumption. We recommend renovations in school buildings with the aim of providing better acoustics, sufficient ventilation, and a reduction in exposure to moisture damage microbes.