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The neighborhoods in which people live play a major role in their wellness and well-being. Many people in the United States and across the globe live in communities that have health and safety risks, such as high rates of violence, inadequate access to health care or nutritious foods, and unsafe air and water due to pollutants. In the US, people with low incomes and people of color are more likely to live in neighborhoods with these risks.^1,2 Specific to toxicant exposures, approximately 73 million people in the US live within three miles of a Superfund site,³ which is a polluted location that requires a long-term response to clean up contamination. Reporting from the Environmental Protection Agency states that residents living near the sites are disproportionately communities of color or those with a lower socioeconomic status.³ In addition, according to 2010 data, more than eight million people in the US live within 1.8 miles of commercial hazardous waste facilities.⁴

According to the American Lung Association’s 2023 State of the Air report, nearly 36% of people in the US live in places with unhealthy levels of air pollution, and people of color are 3.7 times more likely than white people to live in a county with a failing grade for ozone air pollution, short-term particle pollution, or year-round particle pollution.⁵

Studies continue to illustrate environmental exposure inequities, with certain communities and locations disproportionately exposed to toxic chemicals that increase chronic disease risk and development.^6-9 How does awareness of a patient’s physical environment and their neighborhood’s health help to inform a personalized therapeutic plan or treatment approach?

Residential Location, Exposure to Pollutants, and Disease Risk

Assessing the “health” of a patient’s neighborhood may indicate their potential level of exposure to toxic chemicals and provide vital health story information to help determine root causes of chronic conditions. Observational studies have suggested that people who live close to brownfield sites (i.e., former industrial or commercial sites that may be polluted) or close to major roadways may have higher amounts of environmental toxicants in their body.¹⁰ The studies also suggest that people who live close to petrochemical industrial complexes and other industrial pollutant sources, agricultural operations, or areas with increased highway and traffic density may be at increased risk for developing certain cancers such as lung,¹¹ breast,¹² blood,¹³ and colorectal cancer¹⁴ as well as other chronic conditions such as respiratory,¹⁵ metabolic,¹⁶ cardiovascular,^17,18 autoimmune,¹⁹ and neurological diseases.²⁰

A 2022 observational study with data from 774 adult participants from the Detroit Neighborhood Health Study investigated the effect of residential proximity to brownfields, highways, and traffic on blood serum levels of heavy metals such as lead, mercury, manganese, and copper.¹⁰ Researchers found that closer proximity to brownfield sites was associated with increased serum lead and mercury, while living closer to increased highway and traffic density was positively associated with serum lead and manganese.¹⁰

In 2021, an umbrella review of meta-analyses evaluated the associations between environmental risk factors and health outcomes and included the impacts of residential location and surroundings on disease development.¹⁶ Among the reported results, living near major roadways or locations with increased traffic exposure was a suggested risk factor for type 2 diabetes in adults and leukemia in children.¹⁶ Further, residential proximity to petrochemical industrial complexes (PICs) was associated with risk of leukemia development, with one 2020 meta-analysis finding that within a maximum distance of eight kilometers, residential exposure to PICs increased leukemia risk by 36% (pooled RR=1.36, 95% CI=1.14-1.62) compared to controls, regardless of sex and age.¹³ A 2018 meta-analysis that included five cohort studies and one case-control study covering approximately 466,066 individuals found that residents living near PICs had a 19% higher risk of lung cancer compared to those who lived farther away (95% CI=1.06-1.32).¹¹ Researchers noted that subgroup analyses stratified by location showed that only groups in Europe had a significantly greater risk of lung cancer with exposure to PICs; however, groups in other locations, including the US, showed positive risks, but these trends were not statistically significant.¹¹

Recent observational studies have connected other residential locations with potential pollutant exposures and health outcome inequities. Data from the 2008-2013 Survey of the Health of Wisconsin suggested that compared to those living farther away, adults living within 35 kilometers of a coal-fired power plant may have an increased odds of worse pulmonary function as measured by an expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) ratio below 80%.²¹ The analysis also found that while Black individuals were 4.8% of the total sample population, they accounted for 13.3% of those living within the 35-kilometer distance.²¹

Clinical Applications

Potential exposure to pollutants based on residential location is a vital component to consider when receiving a patient’s health story and reflecting timeline details that may influence disease development or progression. In addition, considering the impact of a patient’s physical environment and possible toxicant exposure levels may help focus or prioritize therapeutic treatments.

A 2022 Gallup poll publication found that US adults have substantial worries about specific environmental issues such as exposure to contaminated drinking water and air pollution.²² Yet even if patients do not immediately recognize their daily surroundings as contributors to their health, collaborative patient-practitioner conversations may help to identify potential pollutant sources and to understand a patient’s toxic exposure level and their individual circumstances. For IFM members, the Toxin Exposure Questionnaire in the IFM Toolkit is used to screen a patient’s exposure to toxicants, helps clinicians discover and assess relevant toxic exposures, and tracks a patient’s response to environment and therapeutic interventions. Public online tools such as the EPA’s Toxic Release Inventory Fact Sheet²³ may help to correlate a patient’s neighborhood to pollution and exposure levels.

Assessment of a patient’s total toxic load and recognizing ongoing exposures are essential pieces of practical therapeutic treatments that prioritize the avoidance of toxicant exposures as much as possible while implementing lifestyle modifications to enhance biotransformation pathways and elimination processes. Optimizing a patient’s nutritional status, ensuring adequate fiber and water intake, eating more phytonutrient-dense and diverse foods, and supporting liver function through targeted, nutrient-dense diets such as IFM’s Detox Therapeutic Food Plan are all dietary treatment approaches within the functional medicine model that may help to improve the elimination of toxic compounds and to alleviate toxic burden. Supplements such as probiotics have also been highlighted in human and animal studies for their potential protective effect against the toxicity of some pollutants such as heavy metals.^24-26

Functional medicine provides compelling new perspectives, tools, and interventions that help create the optimal conditions for health and wellness to thrive. Discover the latest research and evidence-based practices at the 2024 Annual International Conference (AIC), Repair, Restore, Regenerate: Healing of the Micro and the Macro Through Functional Medicine. AIC will explore this and other trending topics in medicine and provide clinicians with innovative approaches for advancing health outcomes at every level of care.

Related Articles

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Therapeutic Food Plans: A Component of Personalized Nutrition

Toxin Exposure Questionnaire Tracks Vulnerability to Harmful Chemicals

References

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2. US Environmental Protection Agency Office of Air Quality Planning and Standards Health and Environmental Impacts Division. Policy assessment for the review of the National Ambient Air Quality Standards for Particulate Matter. EPA-452/R-20-002. Environmental Protection Agency. Published January 1, 2020. Accessed July 26, 2023. https://www.epa.gov/system/files/documents/2021-10/final-policy-assessment-for-the-review-of-the-pm-naaqs-01-2020.pdf
3. US Environmental Protection Agency Office of Land and Emergency Management. Population surrounding 1,857 Superfund remedial sites. Environmental Protection Agency. Updated September 2020. Accessed July 26, 2023. https://www.epa.gov/sites/default/files/2015-09/documents/webpopulationrsuperfundsites9.28.15.pdf
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20.  Ayala-Ramirez M, MacNell N, McNamee LE, et al. Association of distance to swine concentrated animal feeding operations with immune-mediated diseases: an exploratory gene-environment study. Environ  Int. 2023;171:107687. doi:1016/j.envint.2022.107687
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