A multilevel analysis of variations in body mass index among adults, Brazil, 2006

To analyze the variation in body mass index (BMI) among adults according to individual factors and environmental characteristics of their city of residence. Data generated in 2006 by the Vigilância de Fatores de Risco e Proteção para Doenças Crônicas por Inquérito Telefônico (VIGITEL--Telephone-based Surveillance of Risk and Protective Factors for Chronic Diseases) system. This survey is based on telephone interviews carried out among probabilistic samples of the population of adults aged > or = 18 years from the 26 Brazilian state capitals and Federal District. Analysis of associated factors included individual socioeconomic and demographic variables and environmental variables pertaining to the city of residence of the 49,395 VIGITEL subjects. Food intake was evaluated based on a 'healthy diet' score and on 'five-a-day' fruit and vegetable intake. Physical activity was evaluated based on frequency and duration of exercise and presence of a place in which to perform physical activity. Associations were tested using multilevel linear models (p