How reproducible is self-reported information on exposure to smoking, drinking, and dietary patterns? Evidence among Brazilian adults in the Pró-Saúde Study.

CONTEXT Epidemiological studies of the validity and reliability of self-reported information on important risk factors for non-communicable chronic diseases are scarce in Brazil. OBJECTIVE We evaluated the test-retest reliability of information--overall and stratified by gender, age and education--on active and passive smoking, alcohol intake and aspects of dietary habits. TYPE OF STUDY Test-retest reliability. SETTING Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil. PARTICIPANTS 192 University employees. PROCEDURES Self-administered questionnaires were completed on two occasions, two weeks apart. MAIN MEASUREMENTS Kappa Statistics; Intraclass Correlation Coefficient. RESULTS Information on smoking status and pack-years smoked had almost perfect levels of agreement, respectively, kappa = 0.97 (95% CI, 0.92-1.00), and intraclass correlation coefficient = 0.93 (CI 95%, 0.89-0.96). Characteristics of alcohol intake yielded substantial levels of agreement (kappa ranging from 0.62 to 0.69). The reproducibility of the information on dietary habits varied from 0.67 to 0.79 (kappa). No clear-cut patterns could be identified comparing information by age or gender. There was a slight tendency towards greater reliability among people with higher levels of education. CONCLUSION The reproducibility of information on smoking, drinking, and dietary patterns ranged from substantial to excellent, as investigated in the Pró-Saúde Study, a longitudinal investigation recently launched in Rio de Janeiro.