Chronic bronchitis in the general population: influence of age, gender and socio-economic conditions.

Chronic bronchitis (CB) is an indicator of an increased risk of developing COPD, but its symptoms are often underestimated. Demographic and socio-economic conditions might influence its prevalence, reporting and impact. Data from a large epidemiological survey of the French general population were analyzed to determine the burden of CB, the magnitude of under-diagnosis and the influence of age, gender and socio-economic conditions. Altogether, 9050 participants aged 45 years or more provided complete data. The prevalence of symptoms and diagnosis of CB was 3.5% and 3.4%, respectively. CB was associated with impaired health status and activity and, in women, work loss. Among subjects with symptoms of CB, only 28.6% declared a known diagnosis of respiratory disease. Factors associated with symptoms of CB in multivariate analysis were male gender, active smoking, lower income and occupational category: the highest prevalence was observed in manual workers (5.6%) and self-employed subjects (5.2%). The under-diagnosis of CB was more marked in men and subjects of higher socio-economic categories. These results confirm that CB is markedly under-diagnosed in the general population. Socio-economic conditions influence both its prevalence (higher in low categories) and rate of diagnosis (lower in high categories), which should be considered when elaborating prevention and detection campaigns.