More Data Better Health – Brazilian People’s Perceptions of Risk Factors for Cancer

The report More Data Better Health – Brazilian People’s Perceptions of Risk Factors for Cancer presents the results of a national survey representative of the Brazilian adult population, aiming to analyze knowledge, attitudes, and behaviors related to cancer prevention. The study provides an exploratory analysis of responses from 6,566 people aged 18 and over, collected between September and October 2025. It is organized around three axes: (i) general perceptions of cancer, including people’s knowledge and experiences; (ii) knowledge about its risk and protective factors; and (iii) behavioral factors and health-related conditions, such as alcohol consumption, diet, physical activity, excess weight, and smoking. This structure allows us to analyze, in an integrated way, how knowledge relates to practices and intentions for change.

The data show that cancer is widely known by the population: 99.1% of Brazilians say they know or have heard of the disease. However, about 27% do not recognize that cancer can be prevented, evidencing an important gap in the understanding of the disease. This gap is also reflected in an unequal recognition of cancer risk factors. Smoking is widely recognized as a risk factor (90.5%), followed by genetic inheritance (88.4%) and excessive sun exposure (88.3%). In contrast, other lifestyle factors are less recognized, such as excess weight (54.1%) and red meat consumption (27.5%).

It is also observed that 40.5% of the population does not recognize breastfeeding as a protective factor against cancer, while 61.3% mistakenly believe that the use of vitamin and mineral supplements reduces the risk of cancer.

Regarding diet, high consumption of ultra-processed foods, sweetened beverages, red meat, and processed meat was observed. Although a relevant portion of the population reports attempting to reduce consumption, there is still a low perception of the risks associated with these products.

As for physical activity, just over half of the population report practicing it, while about 40% of those who do not currently engage in physical activity express an intention to start, indicating a latent demand for behavior change.

The results also show that young people and people with lower incomes have lower levels of knowledge about risk factors and greater exposure to behaviors that are harmful to health. Across all findings, a significant portion of the population demonstrates an intention to adopt healthier habits, pointing to a strategic opportunity for public policies that coordinate information, regulation, and the promotion of healthy environments, with a focus on reducing health inequities.

Regarding smoking behavior, 11.3% of the population reported currently smoking and 18.3% identified themselves as former smokers. Despite the high recognition of smoking as a risk factor, only 13.4% of current or former smokers reported having had access to smoking cessation treatment. With regard to alcohol consumption, approximately half of the population (50.1%) said they do not consume alcoholic beverages. Among those who do consume alcohol, most report having attempted to reduce their consumption.