Liberal state policies during adolescence linked to lower dementia risk in later life

A new study suggests that the political environment in which a person grows up may influence their brain health decades later. Researchers found that older adults who resided in U.S. states with more liberal policies during their adolescence were less likely to develop dementia than those raised in conservative states. These findings point to the potential long-term health consequences of local government decisions made early in a resident’s life. The research was published in the Journal of Health and Social Behavior.

Dementia affects millions of Americans, but the condition is not distributed evenly across the country. Rates of cognitive decline vary substantially depending on geography. Higher prevalence is generally observed in the southern United States compared to the Northeast and West Coast. This geographic variation suggests that environmental factors play a role alongside individual genetics and lifestyle choices. Sociologists refer to these environmental factors as macrosocial determinants. These are the broad political and economic structures that shape daily life.

State governments in the United States hold considerable power over these structures. They control funding for public schools, set minimum wages, and regulate environmental standards. Prior investigations have connected state policies to physical health outcomes such as life expectancy and cardiovascular disease. However, the relationship between these broad policy environments and cognitive aging has remained largely unexplored. Additionally, most previous analysis focused on the policies in place while a person is an adult rather than the environment they experienced as a child.

Meghan Zacher, a researcher at Brown University, led the investigation into this connection. Zacher and her colleagues sought to understand if the political context of adolescence leaves a lasting mark on the brain. They hypothesized that early life conditions might initiate trajectories of health that persist into old age. This concept is known as life course theory. It suggests that exposures during sensitive developmental periods can become biologically embedded. This influences how the body ages long after the exposure has ended.

To test their hypothesis, the research team analyzed data from the Health and Retirement Study. This is a long-running survey that tracks a representative sample of older adults in the United States. The team focused on a group of 6,410 participants who were between the ages of 65 and 80 in the year 2000. None of these individuals had dementia at the start of the analysis. The researchers tracked these individuals for sixteen years to observe who developed the condition.

The team linked each participant to historical data regarding the political orientation of the state where they lived as a teenager. They used a specific metric known as state policy liberalism. This score summarizes the general orientation of state laws on a spectrum from conservative to liberal. The measure aggregates nearly 150 different types of policies enacted between 1936 and 2014.

Liberal policies in this index generally include regulations and wealth redistribution. Examples include higher minimum wages, progressive tax structures, and stricter environmental protections. Conservative policies tend to emphasize economic freedom and cultural traditionalism. These might include right-to-work laws or restrictions on abortion access. By using this aggregate score, the researchers avoided focusing on any single law. Instead, they captured the overall political climate of the state.

The analysis revealed a consistent association between the policy environment of adolescence and cognitive health in old age. Individuals who grew up in states with higher policy liberalism scores faced a lower risk of developing dementia. This relationship held true even when the researchers accounted for the participant’s race, gender, and the education level of their parents.

The team also checked to see if the policy environment where the adults currently lived was the real driver of the results. They found that while current policies matter for other health outcomes, the effect of the adolescent environment on dementia remained distinct.

Living in a liberal state during teenage years provided a protective benefit regardless of whether the person lived in a liberal or conservative state in their older years. The researchers tested for an interaction between past and present environments but found that the benefits of an early liberal context persisted across different adult environments.

A statistical review of the data quantified the reduction in risk. For every standard deviation increase in the liberalism of the adolescent state policy, the risk of developing dementia dropped by approximately 17 percent. This pattern was observed across different demographic groups. The protective association was present for both men and women. It was also present for both non-Hispanic Black and White participants.

The authors then investigated why this connection might exist. They looked at intermediate factors that link early life to later health. The most prominent pathway identified was educational attainment. Liberal policy environments in the past often involved greater investment in public resources, including schools. Participants raised in these environments tended to complete more years of schooling.

Education is believed to create cognitive reserve. This is the brain’s ability to improvise and find alternate ways of getting a job done. This reserve helps the brain cope with the damage caused by diseases like Alzheimer’s. By fostering better educational opportunities, liberal state policies may have helped residents build this neurological resilience.

Beyond education, the researchers looked at adult income and health behaviors. Factors such as smoking, obesity, and cardiovascular conditions like hypertension are known risk factors for dementia. The study found that these elements explained a small portion of the link between state policies and dementia. For instance, states with higher tobacco taxes might reduce smoking rates among young people. This prevents long-term vascular damage that harms the brain.

However, the combined influence of education, economic status, and health behaviors only accounted for about one-third of the total association. This implies that other mechanisms are likely at work. It suggests that the sociopolitical environment impacts biological development in ways that standard health metrics do not fully capture. It is possible that unmeasured factors such as air quality or stress levels also play a role.

These results align with broader research linking state governance to population well-being. A recent analysis by Nancy Krieger and colleagues found that states with conservative political leadership between 2012 and 2024 experienced higher rates of premature death and infant mortality compared to more liberal states.

While that research focused on immediate outcomes like vaccine uptake and food security, the new findings on dementia suggest that these political contexts also exert a delayed influence that manifests decades later. Both studies underscore the idea that the ideological orientation of state governments plays a central role in shaping the physical and cognitive health of residents.

While the results of the new research identify a strong pattern, the study design has limitations. Because the research is observational, it cannot definitively prove that liberal policies caused the reduction in dementia cases. It is possible that unmeasured factors distinguish states with different political orientations.

The researchers attempted to mitigate this by using statistical techniques that compare individuals born in the same state. These sensitivity analyses supported the main conclusion. Even among people born in the same location, exposure to different policy eras mattered.

Future research is needed to explore the specific types of policies that drive might these benefits. Understanding whether education funding, environmental regulations, or social safety nets are the primary drivers could help guide public health interventions. The authors suggest that policymakers should consider the long-term cognitive implications of state-level legislation. As the population ages, understanding the upstream causes of dementia becomes increasingly necessary for public health planning.

The study, “State Policy Liberalism in Adolescence and Risk for Dementia from 2000 to 2016 among Older U.S. Adults,” was authored by Meghan Zacher, Samantha Brady, and Susan E. Short.