ConVid - Behavior Survey by the Internet during the COVID-19 pandemic in Brazil: conception and application methodology.

The ConVid - Behavior Survey was conducted in Brazil from April 24 to May 24, 2020, aiming to investigate changes in lifestyles and health conditions during the COVID-19 pandemic. In this article, we present the conception and methodology of the research. We used a cross-sectional study using an Internet questionnaire, with questions validated in previous health surveys. The sampling method "virtual snowball" was used, as well as post-stratification procedures. The results related to chronic non-communicable diseases and pre-pandemic lifestyles were compared with estimates from the 2013 Brazilian National Health Survey and 2019 Surveillance of Risk and Protective Factors for Chronic Diseases by Telephone Survey. The total sample was 45,161 people. After data weighing, the sample distributions of demographic variables were similar to population variables. Only people with a low schooling level were underrepresented. The comparison with the previous results showed similarity in most estimates: recommended consumption of fruits and vegetables (22.1%), recommended physical activity (35.2%), tobacco smoking habit (12.3%), frequent and abusive alcohol consumption (6.7%), obesity (21.2%), self-reported prevalence of hypertension (18.6%), diabetes (7.1%), and heart disease (4.4%). The online survey made it possible to know the population's health conditions during the pandemic. The similarity of the indicators with those obtained in traditional research allowed the validation of the mean estimates. Studies are needed to investigate how the endogenous effects of virtual social networks can be considered when estimating variance.