Environmental exposure as an independent risk factor of chronic bronchitis in northwest Russia.

Background: In some parts of the northwest Russia, Murmansk region, high exposures to heavy mining and refining industrial air pollution, especially sulphur dioxide, have been documented.

Objective: Our aim was to evaluate whether living in the mining area would be an independent risk factor of the respiratory symptoms.

Design: A cross-sectional survey of 200 Murmansk region adult citizens was performed.