Study design and data collection

This study analyzed the trends in coverage of mammography and cervical oncotic cytological tests using data covering the years between 2007 and 2018 that were collected from the Surveillance of Risk and Protection Factors for Chronic Diseases by Telephone Survey (Vigitel).

Vigitel is a survey conducted through telephone calls in the Brazilian population, which annually monitors the main chronic noncommunicable diseases (NCDs) and their risk and protection factors. This survey is conducted on a representative sample of the adult population in Brazil (≥ 18 years old) living in households with at least one fixed telephone line, in each of the 26 Brazilian state capitals and in the Federal District. Every year, approximately 2,000 people answer the survey questions and, over the years in which Vigitel has been conducted, 382,255 adult women have been interviewed. Survey professionals have applied some adjustment procedures that have taken sex, age and education levels into account, with the aim of reducing the non-representation bias inherent to telephone interviews and seeking to make the sample distribution similar to the sociodemographic characteristics of the adult population of each state capital.⁸ Details on the sampling and data collection process can be found in the published Vigitel results.^8,9