Examining Health-Related Risk Factors for Stroke and the Role of Health Insurance in Moderating Lifestyle: Evidence from the BRFSS
1University of Pennsylvania, School of Social Policy & Practice
*Email: jn1014@upenn.eduAbstract
Stroke remains one of the leading causes of mortality and disability in the United States. However, there are still disparities in how lifestyle and healthcare access shape stroke outcomes. This study investigates the associations between smoking, alcohol consumption, body mass index (BMI), mental and physical health, sleep duration, health insurance status, and stroke incidence using data from the 2022 Behavioral Risk Factor Surveillance System (BRFSS, N = 77,146). Logistic regression models are applied to estimate the direct effects of these factors on stroke risk, as well as the moderating role of health insurance.
The results indicate that while some traditional risk factors, such as smoking and alcohol use, show weaker or unexpected associations with stroke in this dataset, mental health, physical health, and health insurance coverage demonstrate significant protective effects. In particular, interaction analyzes reveal that health insurance strengthens the beneficial impact of better mental and physical health and adequate sleep on reducing stroke risk. These findings highlight the importance of considering access to healthcare not only as an independent determinant of health, but also as a moderator that amplifies the benefits of healthy lifestyles.
This study contributes to public health research by underscoring the complex interaction between behavioral risk factors and structural determinants such as health insurance. Policies that expand access to affordable healthcare should improve the effectiveness of lifestyle-based prevention strategies and help reduce stroke incidence among disadvantaged populations.
Article notes
Competing Interest Statement
The authors have declared no competing interest.
Funding Statement
This study did not receive any funding.
Introduction
Stroke has been identified as a significant public health concern and it is one of the leading causes of mortality and disability globally[1]. According to most studies, stroke is still the primary cause of mortality in the US and has been placing burdens on healthcare systems [2]. Therefore, it is crucial to identify potential risk factors and investigate their association with stroke. In previous studies, smoking, alcohol consumption, mental and physical health problems, and unhealthy Body Mass Index (BMI) have already been identified as the main attributes of stroke[3]. However, neither the extent of these variables in stroke nor their interaction effect has been pervasively studied in the population-level research literature.
The purpose of this study is to investigate the associations between the health-related factors mentioned above and stroke occurrence using a logistic regression model. The study aims to determine the extent to which these characteristics are associated. Furthermore, the study intends to investigate the possible interaction effects of health insurance status and how health insurance interacts with other variables. Understanding this interaction is critical to figuring out how the availability of healthcare interacts with other stroke risk factors. This research is based on data from the Centers for Disease Control and Prevention (CDC) Behavioral Risk Factor Surveillance System (BRFSS), an annual health survey that collects detailed health information from over 400,000 adults in the United States. The BRFSS collects data on health behaviors, chronic illnesses, and socioeconomic factors. The rich data types included in the dataset make it a valuable resource for studying public health concerns. Although most previous studies have employed the BRFSS to investigate various health outcomes, this study uniquely focuses on the interaction of health insurance status and lifestyle factors. It intends to investigate how healthcare access affects stroke preventive efforts.
However, disparities still exist in stroke outcomes across different populations even though there has been progress in stroke prevention [4]. The disparity is particularly prevalent among those with limited access to healthcare [5]. Also, socioeconomic factors such as access to health insurance have a significant impact on health outcomes[6]. People without health insurance may encounter difficulties getting preventative care or early stroke therapies [7]. Understanding how health insurance modifies the association between risk factors and stroke can aid in the development of a more effective intervention plan to minimize stroke incidence in disadvantaged populations.
By employing the logistic regression model, this study aims to answer the following research questions:
- What potential relationships exist among smoking, alcohol consumption, mental and physical health, sleeping hours, BMI, health insurance, sex and stroke?
- Is there an interaction effect between health insurance status and other variables?
These findings will help to deepen our understanding of the relationship between stroke risk variables and emphasize the relevance of health equality in stroke prevention initiatives. Identifying the interaction effects of health insurance may lead to more effective public health measures for lowering stroke rates in marginalized populations.
Method
The purpose of this study is to look at the potential relationships between health-related characteristics (cigarette usage, alcohol intake, BMI, mental and physical health, sleeping hours, health insurance, and sex) and stroke incidence. Meanwhile, the study seeks to determine whether health insurance status can interact with the rest of the variables. To achieve these objectives, secondary data analysis will be carried out using the BRFSS data.
Data
The data used in this study were obtained in 2022 by landline and mobile phone surveys in all 50 states, the District of Columbia, Guam, Puerto Rico, and the United States Virgin Islands [8]. The landline respondents were selected through the disproportionate stratified sampling (DSS) method, while cell phone respondents were chosen randomly, and each person had an equal chance of being chosen. The dataset has 328 variables and a total of 445,132 observations. Missing values are denoted by “NA.” The data were retrieved from the CDC’s official website and saved in SAS format.
Because the data was obtained using landline and cell phone surveys, various biases such as non-response, decline to answer, and incomplete interviews are possible according to [9]. To reduce potential bias, responses such as blank, decline to answer, or Not sure/Don’t know will be removed.
Variables
From the 328 variables included in the dataset, eight are considered in the analysis:
- Smoke: Smoke at least 100 cigarettes (0 = No, 1 = Yes)
- Alcohol: Average alcoholic beverages per day over the past 30 days
- BMI: body mass index (BMI)
- Mental: Number of Days Mental Health Not Good per month (0-31)
- Physical: Number of Days Physical Health Not Good per month (0-31)
- Sleeping: How many hours to sleep per day (0-24)
- Insurance: Have any health insurance or not (0 = No, 1 = Yes)
- Sex: Male or Female
- Stroke: Ever diagnosed with stroke or not (0 = No, 1 = Yes)
Analysis
All data analyses will be conducted using R software (R Foundation for Statistical Computing). Descriptive statistics will first be performed to summarize all the variables. To avoid multicollinearity, an initial exploratory data analysis (EDA) will be performed to assess the correlation between the dependent and independent variables, as well as the correlation between the independent variables.
Following the fundamental EDA, a logistic regression model will be constructed to investigate several independent variables. Odds ratios (OR), confidence intervals (CI), and p-values will be applied to evaluate the extent of association and the statistical significance of each variable.
To further explore the moderating role of health insurance on the relation-ships between the rest of the variables and the risk of stroke, interaction effects were included in the logistic regression models. Interaction terms were established between health insurance and each of the independent variables: Smoke, Alcohol, Mental, Physical,Sleeping, BMI, and Sex.
These interactions were explored to see if the effect of each factor on stroke risk is influenced by health insurance status. The significance of these interaction effects was determined by analysis of variance (ANOVA). A significant interaction implies that the relationship between the independent variable and stroke can be different if the health insurance status changes.
Results
Descriptive Statistics
The dataset used for analysis includes 77,146 completed records, with 2.92% reporting a history of stroke. The sample had a smoking prevalence of 40.98% and an average daily alcohol consumption of 2.4 drinks. Respondents had an average of 10.02 days of poor mental health and 4.69 days of poor physical health in the previous 30 days. The average sleep duration was 6.84 hours per day.
In terms of health coverage, 94.69% had health insurance. The sample was fairly balanced by gender, with 44.48% male and 55.52% female participation. These numbers offer a diverse sample of health behaviors and outcomes and enable further investigation of stroke risk and associated factors.
Bivariate Analysis
The biserial correlations between the independent variable and the dependent variable were calculated to assess the degree of relationship between the two variables. The variable with the strongest connection is Physical (r=0.131), suggesting that poor physical health may be slightly connected to stroke. The biserial correlation results show weak connections between the continuous variables and Stroke. The correlations between Mental, Alcohol, Sleeping, and BMI are weak or near zero. Given the weak correlations, the continuous factors are unlikely to be strong individual predictors of Stroke. This emphasizes the need for a multivariate logistic model, as well as consideration of the potential interaction effect.
Table 2 presents the relationships between the five continuous variables: Alcohol, Mental, Physical, Sleeping, and BMI. The Spearman correlation coefficient has been applied and the coefficients range from −0.15 to 0.23, with the strongest being between Mental and Physical (0.23). This shows that the variables are generally independent of one another. As a result, multicollinearity is not an issue in the following multivariate logistic regression.
Associations between nominal variables (Smoke, Health, Insurance) and the outcome variable (Stroke) have been identified based on the chi-squared tests. All these variables have been found associated with the outcome (p<0.001, p = 0.034, p <0.001, respectively).
Multivariate Logistic Regression
In this section, logistic regression was used to look at the relationship between lifestyle factors and stroke incidence. The study indicated that those who have smoked more than 100 cigarettes have a significantly decreased risk of stroke (OR = 0.524, p <0.001). This contradicts previous research which has consistently shown that smoking increases stroke risk[10]. Alcohol use was associated with a slightly higher risk of stroke (OR = 1.01), but the effect was not statistically significant (p = 0.185). The p-value indicates that Alcohol has no substantial impact on stroke risk in this analysis. This finding also contradicts previous research which suggests less alcohol use came with lower stroke risk [11]. Both mental and physical health had small but statistically significant protective effects against stroke, with fewer unhealthy days associated with a lower likelihood of stroke (Mental OR = 0.991, p <0.001; Physical OR = 0.950, p <0.001). Despite research indicating the good effects of sleep on health [12], sleep duration did not reveal a significant influence on stroke risk (OR = 0.991, p = 0.499). BMI was not statistically significant (OR = 1.000, p = 0.211), indicating that body mass index does not influence stroke risk in this sample. Insured persons had a significantly lower stroke risk (OR = 0.696, p = 0.0007), highlighting the relevance of access to healthcare resources in reducing stroke incidence. As for sex, Males have about 11% lower odds of the outcome compared to females, and this difference is statistically significant (OR = 0.8913, p = 0.0091).
Interaction effect
In this part, it will be determined whether the effect of having health insurance can be mitigated by other factors. New models with interactions will be created and compared to the first logistic model using ANOVA. Table 4 compares the results of ANOVA between the initial logistic model and the model with interactions. According to the ANOVA results of interaction effects, certain variables have statistically significant interactions with health insurance status. Both the interactions of Mental and the interaction of Physical with health insurance are statistically significant (p = 0.023 and p = 0.034, respectively). This suggests that these variables can have a different impact on stroke risk when they are combined with health insurance. Furthermore, the interaction effect of Sleeping is extremely significant (p = 0.001). This indicates that sleeping hours and health insurance status play a vital role in determining stroke risk. However, interactions between Smoke, Alcohol, BMI (body mass index), and Sex (gender) did not have statistical significance, indicating that their combined effects with health insurance are less influential in this study’s context.
Discussion
This study aimed to examine the relationships between lifestyle factors and stroke risk, with a special emphasis on whether health insurance status modifies these associations. The logistic model used on the BRFSS dataset allowed for the assessment of both direct effects and interactions related to stroke risk, providing insights into how these lifestyle factors influence stroke outcomes.
The findings demonstrated that several variables can significantly influence stroke risk. Contrary to most literature that identifies smoking as a major risk factor for stroke [10], smoking in this sample was unexpectedly found to be negatively associated with stroke. This anomaly may be a result of self-reported bias or limitations in the smoking measurement (i.e., ever smoked at least 100 cigarettes). Such bias can potentially result in an inaccurate capture of current smoking behaviors. Similarly, No significant association was found between alcohol consumption and stroke risk in this analysis and this is also contrary to literature that identifies alcohol consumption as a risk factor[13].
Both mental and physical health, as measured by the number of unwell days in the previous month, demonstrated minor but statistically significant protective effects against stroke. This implies that persons who have fewer days of poor mental or physical health are at a lower risk of stroke, underlining the importance of general well-being in stroke prevention. Sleeping hours also showed a protective impact, with longer sleep hours reducing stroke risk. The findings are consistent with existing research[14] demonstrating that proper sleep benefits cardiovascular health.
Notably, health insurance had a robust protective effect against stroke risk. Such an effect highlighted the critical role of healthcare access. People having insurance were considerably less likely to have a stroke. This could be attributed to improved access to preventive services such as regular health screenings and early detection of cardiovascular disease [15]. The interaction effect evaluation also revealed that health insurance can moderate the effects of mental health, physical health, and sleeping hours on stroke risk. Specifically, insured individuals with fewer poor mental or physical health days or longer sleep duration had an even lower stroke risk. This implies that access to healthcare magnifies the benefits of good health and enough rest.
However, the interaction effects of health insurance on smoking, alcohol consumption, BMI, and sex were not statistically significant. This suggests that healthcare access may have a more indirect influence on these behaviors and the influence is likely to be caused by broader social or personal factors beyond insurance coverage.
This study’s strengths include its large, representative sample and the exploration of interaction effects with a focus on the moderating role of health insurance. However, some limitations must be acknowledged. The reliance on self-reported data introduces potential biases, especially regarding sensitive behaviors like smoking and alcohol use. Additionally, the cross-sectional design of the BRFSS limits causal inferences about the relationships between lifestyle factors and stroke risk. Future longitudinal research could delve deep into these associations over time. Additionally, the logistic regression model can be applied to interpret the relationship between the dependent variable and the independent variable, but it is not capable of predicting the occurrence of stroke accurately based on the independent variables above due to the imbalanced data. Alternative prediction algorithms, such as random forest, as well as strategies for dealing with imbalanced data, such as the Synthetic Minority Over-sampling Technique (SMOTE), can be used to improve prediction[16].
Conclusion
This study provides valuable insights into the relationship between lifestyle factors and stroke risk, with a focus on how health insurance status moderates these associations. The findings indicate that smoking, alcohol consumption, mental and physical health, sleep duration, and health insurance significantly influence stroke outcomes. Health insurance can enhance the protective effects of good mental health, physical health, and adequate sleep. This interaction effect highlights the crucial role of healthcare access in reducing stroke risk. While interactions with smoking, alcohol consumption, BMI, and sex were not significant. The results emphasize the need for further research to explore these complex relationships. Overall, this study highlights the importance of addressing both lifestyle behaviors and healthcare access in stroke prevention strategies. To minimize the risk of stroke and improve cardiovascular health outcomes, future initiatives should focus on promoting healthy behaviors and increasing access to healthcare for disadvantaged people.
Data Availability
All data produced are available online at: https://www.cdc.gov/brfss/index.html