['Indoor exposure to mould and dampness is frequently associated with asthma symptoms with and without lung function changes. However, the mechanisms contributing to this threat to respiratory health are only partly understood.', 'To investigate the contribution of recent exposure to mould and dampness in the living room or bedroom to respiratory health in a general practice-based cohort of 526 asthmatic children.', 'Parents were questioned about home characteristics, including moulds and dampness. The level of asthma control was evaluated in their participating children by means of asthma symptoms, peak expiratory flow (PEF) variability, severity of airway hyperresponsiveness (AHR), and medication usage.', 'Children exposed to indoor moulds and dampness more often had severe AHR compared with non-exposed (42% vs. 16%; P< or =0.001). They also showed an increased PEF variability (11.3% vs. 8.4%; P=0.03) and, however, not significant, more frequent asthma symptoms. The use of controller medication was not significantly different between exposed and non-exposed children. After adjustment for gender, age, smoking, exposure to parental smoking, parental education, pet ownership, presence of inhalant allergy, use of controller medication, health care center, and season of study assessment, the odds ratio for severe AHR in exposed children was 3.95 [95% confidence interval (CI): 1.82-8.57].'] Is residential exposure to mould and dampness associated with adverse respiratory health?