The aim of the present study was to identify risk factors for community-acquired pneumonia (CAP), with special emphasis on modifiable risk factors and those applicable to the general population. A population-based, case-control study was conducted, with a target population of 859,033 inhabitants aged >14 yrs. A total of 1,336 patients with confirmed CAP were matched to control subjects by age, sex and primary centre over 1 yr. In the univariate analysis, outstanding risk factors were passive smoking in never-smokers aged >65 yrs, heavy alcohol intake, contact with pets, households with >10 people, contact with children, interventions on the upper airways and poor dental health. Risky treatments included amiodarone, N-acetylcysteine and oral steroids. Influenza and pneumococcal vaccine, and visiting the dentist were protective factors. Multivariable analysis confirmed cigarette smoking, usual contact with children, sudden changes of temperature at work, inhalation therapy (particularly containing steroids and using plastic pear-spacers), oxygen therapy, asthma and chronic bronchitis as independent risk factors. Interventions for reducing community-acquired pneumonia should integrate health habits and lifestyle factors related to household, work and community, together with individual clinical conditions, comorbidities and oral or inhaled regular treatments. Prevention would include vaccination, dental hygiene and avoidance of upper respiratory colonisation.
