Introduction

Excessive exposure to ultraviolet (UV) radiation is a well-established risk factor for skin cancer, the most prevalent form of cancer globally, with over 1.5 million new cases diagnosed annually worldwide1. In Brazil, a country characterized by its predominantly tropical climate and high levels of solar radiation, understanding sun protection behaviors is crucial for developing effective public health strategies to mitigate this burden. Despite ongoing awareness campaigns, the adoption of sun protection measures remains inconsistent, with significant disparities across sociodemographic groups2,3,4.

Research has consistently demonstrated that sun protection practices are influenced by a complex interplay of factors, including gender, age, education level, socioeconomic status, and skin color. For instance, studies have shown that individuals with higher educational attainment and income levels are more likely to engage in protective behaviors, such as regular sunscreen use, during leisure activities5. Conversely, those with lower socioeconomic status often face increased occupational sun exposure and limited access to protective resources, exacerbating their risk of UV-related harm6. Additionally, cultural perceptions and misconceptions about the risks of UV exposure among darker-skinned populations can lead to inadequate sun protection, despite evidence that skin cancer, though less common, can still occur in these groups7.

This study aims to analyze the temporal trends in sun protection behaviors among Brazilian adults from 2007 to 2010, using data from the Brazilian Surveillance System for Risk and Protective Factors for Chronic Diseases by Telephone Survey (Vigitel). By examining the prevalence of sunscreen use, hats/umbrellas, and protective clothing, as well as their association with sociodemographic factors, we seek to provide evidence-based insights to inform targeted interventions and public health policies. Our findings highlight the critical role of socioeconomic disparities in shaping sun protection behaviors and underscore the need for equitable strategies to reduce skin cancer incidence in Brazil.

The objective of this study is to evaluate the prevalence of sun protection behaviors among Brazilian adults between 2007 and 2010 and to analyze their association with educational attainment. By focusing on education as a key social determinant of health, this study aims to contribute to public health efforts to reduce inequalities in sun protection. Findings from this analysis can support the development of targeted health promotion strategies, particularly for adults with lower education levels, to increase awareness and adoption of sun protection measures.

Methodology

Study design and data source

This cross-sectional study used data from the Surveillance System for Risk and Protective Factors for Chronic Diseases by Telephone Survey (Vigitel), conducted annually by the Brazilian Ministry of Health. Vigitel aims to monitor trends in risk and protective factors for chronic non-communicable diseases (NCDs) among adults living in the capitals of the Brazilian states and the Federal District.

Sampling and data collection

Vigitel uses a probabilistic sampling method, stratified by geographic region and based on households with fixed telephone lines. The sampling process is conducted in two stages: first, residential telephone lines are drawn; then, one adult resident from each household is randomly selected to answer the survey.

The sample size established for the survey between 2006 and 2019 corresponded to approximately two thousand (2000) individuals in each city to estimate, with a 95% confidence coefficient and a maximum error of around two percentage points, the frequency of risk and protective factors for CNCDs in the adult population of each of the capitals of the 26 Brazilian states and the Federal District. The methodological details and weighting of the sampling design are described in official Vigitel publications8.

This study analyzed data collected between 2007 and 2010, since these were the editions that investigated protection against sun exposure among Brazilian adults, totaling 217,310 individuals.

Study variables

The questionnaire used in this study is part of the Vigitel System, which has been used and validated since 2006. The Vigitel questionnaire is publicly available and can be accessed at the following link: https://www.gov.br/saude/pt-br/centrais-de-conteudo/publicacoes/svsa/vigitel. This link provides access to the questionnaire for all editions of the survey, including the one used in our study.

Outcome variable

The outcome variable was defined as the proportion of individuals reporting protective behaviors against ultraviolet (UV) radiation, with the question: “When you are exposed to the sun for more than 30 min, whether walking on the street, at work, or during leisure, do you usually use any protection against the sun?”. The indicator of protection against ultraviolet radiation adopted by Vigitel takes into account the proportion of individuals who do not usually expose themselves to the sun for more than 30 min a day or do so using sunscreen and/or a hat/umbrella and suitable clothing (considered to be effective protection against ultraviolet rays).

Additionally, for the years 2009 and 2010, the specific type of protection used was also evaluated through the question: “What type of protection do you usually use?” (multiple responses allowed), with the following options: sunscreen, hat or umbrella, appropriate clothing and report avoiding sun exposure. This allowed respondents to report more than one method of protection. The analyses on different types of sun protection were conducted exclusively with data from these two years, as this information was not available for other periods of the study9.

Statistical analysis

All statistical analyses accounted for the study design using the rake weighting method employed in Vigitel. This weighting approach, based on iterative proportional fitting, ensures that the survey data is representative of the Brazilian adult population by adjusting for key demographic distributions obtained from census data10. All analyses were conducted using Stata, incorporating sample weights via the “survey” module to maintain population-level representativeness.

Categorical variables were described using proportions, presented with prevalence estimates, standard errors, confidence intervals, and coefficients of variation. Associations between sun protection behaviors (individuals who reported using at least one sun protection method, including does not usually expose to the sun, sunscreen, hats/umbrellas, or protective clothing), and the explanatory variables were analyzed using Poisson regression models with robust variance estimation. This approach was chosen due to its suitability for modeling prevalence ratios in cross-sectional studies. Unadjusted and adjusted prevalence ratios (PRs) were estimated with corresponding 95% confidence intervals. For selecting variables in the multivariate model, we used the stepwise backward criterion, initially including all variables with a p-value < 0.20 in the univariate analysis and those considered biologically plausible. Variables were removed from the model one by one until all presented p < 0.05, ensuring that only statistically significant associations remained in the final model.

We tested the assumptions of the analysis and validated all of them, ensuring the robustness of our findings. We also assessed the variance inflation factor (VIF) to check for multicollinearity, and all VIF values were within acceptable limits (< 10)11. For all analyses, we calculated the coefficient of variation to evaluate the precision and consistency of our results.

Results

The overall prevalence of individuals who did not use any sun protection remained relatively stable over the study period, with rates fluctuating between 45.9% (2007) and 52.5% (2010) (Fig. 1). In contrast, 11.7% of respondents in 2007, 5.4% in 2008, 5.1% in 2009, and 3.7% in 2010 reported not usually exposing themselves to the sun. The most common forms of protection were the use of sunscreen (38.9% in 2010), followed by the use of hats or umbrellas (7.2% in 2010), with only 1.2% using appropriate clothing methods (Fig. 2). As these were multiple-response questions, the total percentages may exceed the overall prevalence of protection use.

Fig. 1
figure 1

Temporal trends in sun protection behaviors behaviors in Brazil (Vigitel 2007–2010). Percentage of individuals who did not use any sun protection between 2007 and 2010, showing trends over time.

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Fig. 2
figure 2

Distribution of sun protection methods used in Brazil (Vigitel 2007–2010). Percentage of individuals using different sun protection measures, including does not usually expose to the sun, sunscreen, hats/umbrellas, and protective clothing. Data from 2007 and 2010. No data is available for sunscreen, hat, umbrella, or appropriate clothing use in 2007 and 2008.

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The supplementary materialS1 illustrates the regional distribution of sun protection behaviors. The highest prevalence of sun protection use was observed in Salvador (54.2%) and Rio de Janeiro (54.5%), while the lowest prevalence was found in Florianópolis (37.3%) and Palmas (43.9%). Of the forms of protection, sunscreen was most common in Florianópolis (40.7%), and least common in Teresina (21.6%). The use of hats or umbrellas was more common in Belém (10.0%) and less common in São Paulo (3.5%).

As for sociodemographic characteristics, the majority of participants were male (54.3%), aged between 25 and 44 (61.2%), and had between 9 and 11 years of schooling (42.5%). The majority of respondents identified themselves as brown (56.8%), had up to 8 years of schooling (42.8%), and were married or in a stable union (64.1%). Of the behavioral variables, 14.7% were smokers, 62.1% consumed alcohol, 31.5% were overweight, and 14.1% were obese. Of the health-related variables, 4.7% self-reported their health as bad to very bad, 24.6% had hypertension, and 6.3% had diabetes (Table 1).

Table 1 Prevalence of sun protection behaviors by sociodemographic factors (Vigitel 2007–2010).
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Table 2 presents the multivariate model of factors associated with sun protection behaviors. Women were more likely to use sun protection than men (PR = 1.46), as were older adults compared to those aged 18–24 (PR = 1.16–1.32). Higher education levels were positively associated with sun protection use (PR = 1.21–1.48). Lower prevalence of sun protection use was also observed among individuals who smoked (PR = 0.92), consumed alcohol (PR = 0.97), were overweight (PR = 0.95) or obese (PR = 0.87), reported poor/very poor health (PR = 0.87), or had hypertension (PR = 0.95) or diabetes (PR = 0.96).

Table 2 Association between sociodemographic, behavioral and health variables with sun protection behaviors (Vigitel 2007–2010).
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Table 3 details the associations between educational attainment and the specific types of sun protection used. Sunscreen use showed the most pronounced disparities: individuals with 9 to 11 years had a 78% higher prevalence of use (PR = 1.78; 95% CI 1.70–1.88), and those 12 or more years of education had a 2.63 times higher prevalence ratio of using sunscreen compared to those with 0 to 8 years of education (PR = 2.63; 95% CI 2.51–2.77). In contrast, avoidance of sun exposure was less common among those with higher education, particularly among those aged 12 years or more (PR = 0.71; 95% CI 0.65–0.77), as was the use of protective clothing, in which individuals with 12 or more years of education reported less use of appropriate clothing (PR = 0.70; 95% CI 0.61–0.79).

Table 3 Association of educational attainment with type of sun protection used (Vigitel 2007–2010).
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Discussion

This study reveals marked educational inequalities in sun protection behaviors among Brazilian adults, based on nationally representative data collected between 2007 and 2010. Our findings show that individuals with higher educational attainment were significantly more likely to engage in sun protection practices, especially sunscreen use, while those with fewer years of schooling relied more frequently on physical barriers such as hats and clothing or avoided sun exposure.

The prevalence of non-use of sunscreen varies greatly between studies, suggesting that out of every 10 people, one to seven do not use 4,12,13,14,15,16sunscreen. In Brazil, a study conducted in Pelotas (RS) reported non-use of sunscreen at 39.2% at the beach, 69.8% during sports, and 86.3% at work12. Our findings align with these results, showing that sunscreen is the most commonly used form of sun protection. The disparity in sunscreen use is interesting; individuals with 12 or more years of education were over twice as likely to report using sunscreen as those with up to eight years of schooling. This aligns with previous studies in Brazil and other countries, indicating that financial constraints and limited health literacy are major obstacles to sunscreen use among low-income and less-educated populations5,17. Unlike other forms of sun protection, sunscreen entails recurrent costs and is often perceived not as a health item, but as a cosmetic product, limiting its accessibility. In this context, public policies such as tax exemptions or public distribution programs could be effective in reducing inequalities in access to sunscreen3.

Interestingly, our results also indicate that individuals with higher education were less likely to use protective clothing or report avoiding sun exposure. This finding may reflect behavioral preferences or lifestyle differences rather than simply socioeconomic constraints. For example, individuals in white-collar occupations or urban settings may prioritize sunscreen for convenience or aesthetic reasons, while those in outdoor occupations may rely more on hats or clothing as protective strategies. The influence of sex and age on sun protection was also evident, with women and older adults more likely to use some form of protection. These patterns are consistent with studies showing that women are generally more engaged in preventive health behaviors, including sun protection. Older adults may have accumulated more knowledge about the risks of sun exposure or may be more concerned with visible signs of skin aging, which could motivate greater adherence to sun protection recommendations5,6,18.

Regional differences in sun protection behaviors were also observed, with higher use of sun protection in coastal cities like Salvador and Rio de Janeiro and lower prevalence in southern regions such as Florianópolis. These variations may be related to differences in climate, cultural norms, and occupational sun exposure. For example, populations in warmer, tropical climates tend to be more aware of the risks of sun exposure and more likely to adopt protective measures2,3. However, in cities with high UV exposure but lower sun protection habits, such as Teresina, targeted educational interventions are needed to address these gaps19.

This study has some limitations. First, the data were collected between 2007 and 2010, and although these are the most recent nationally representative data available in Brazil with detailed information on sun protection behaviors, it is possible that individual practices have evolved in the last decade. However, we emphasize that structural determinants of health behaviors, such as socioeconomic inequalities, regional disparities, and access to preventive resources, tend to persist over time20,21 and appear to continue to influence sun protection patterns in the Brazilian population, as well as other health behaviors. In this sense, the associations identified in this study may remain relevant for understanding the social determinants of sun exposure and for guiding future health promotion strategies. Furthermore, these results may serve as a basis for future comparisons, especially if new national surveys are conducted.

It is also important to note that sun protection behaviors, such as sunscreen use or protective clothing, are often shaped by long-standing cultural norms and access conditions that gradually change. Therefore, our findings may still reflect current barriers and opportunities for intervention. Finally, the study did not explore other sun protection strategies that are considered primary prevention measures and should be encouraged in future health promotion initiatives and research.

Conclusion

This study demonstrates that educational attainment is a key determinant of sun protection behaviors among Brazilian adults. Individuals with higher education are significantly more likely to use sunscreen, while those with lower education levels report greater use of physical barriers or no protection at all. Women, older adults, and those with healthier behaviors were also more engaged in sun protection. These patterns reflect structural inequalities in access, knowledge, and preferences.