[Epidemiological data on chronic bronchitis in France].
DEFINITIONS: Cough and expectorations present for at least 3 months every year for at least 2 consecutive years are the characteristic feature of chronic bronchitis. Pulmonary emphysema is a permanent distension of the air spaces beyond the bronchioles with destruction of the alveolar walls. Chronic obstructive pulmonary disease (COPD), which often develops after chronic bronchitis, is defined as an obstructive ventilatory syndrome demonstrated by a forced expiratory volume in 1 second/vital capacity (FEV1/VC) ratio below 70%. Acute exacerbation of chronic bronchitis is characterized by worsening cough, expectoration and/or dyspnea. RISK FACTORS: Active smoking is a predominant risk factor for COPD; the decrease in FEV1 is tightly correlated with individual sensitivity to tobacco smoke. Other risk factors have been identified: occupational exposure to airborne contaminants, alpha-anti-tripsin deficiency. EPIDEMIOLOGICAL DATA: A recent survey showed that the prevalence of chronic bronchitis in the adult population in France aged over 25 years is an estimated 1.2 to 2 million people without co-morbidity and an estimated 1.6 to 2.8 million including people with co-morbidity (for instance asthma). The annual death toll reaches 10,000 to 12,000. MANAGEMENT: In patients without co-morbidity, only about 30% of all cases of chronic bronchitis are diagnosed. Medical care is given to about 15%. The impact of acute exacerbations (average 3 episodes per year according to the survey), both in number and in terms of quality of life, would be underestimated.