Using Indoor HEPA Air Purifiers as a Means of Diabetes Prevention

Mounting evidence suggests that air pollution contributes to the rapidly growing type 2 diabetes epidemic. Epidemiological studies have also found surrounding air pollutant exposures, such as particularly fine particles (PM2.5) and nitrogen dioxide (NO2) to be associated with an increased risk for diabetes. Our previous study in Hispanic adults consistently found that up to 58 days of cumulative exposure to PM2.5 was associated with higher fasting glucose and insulin levels.

Chen Z, Salam MT, Toledo-Corral C, et al. Ambient Air Pollutants Have Adverse Effects on Insulin and Glucose Homeostasis in Mexican Americans. Diabetes Care. 2016;39(4):547-554. 

High Efficiency Particulate Air (HEPA) purifiers can theoretically reduce indoor PM2.5 levels by 40% to >90%(1,3, 5-9) and can improve acute cardiovascular outcomes after using such a device for a short period (3 days to 2-month)(1-4). However, no published studies have evaluated the potential benefits of a longer-term indoor HEPA filtration intervention in improving cardio-metabolic profiles in at-risk adults. Here we propose to conduct a 6-month residential HEPA filtration trial in individuals with a baseline health condition of elevated risk for type 2 diabetes.

The study population will consist of 52 adults residing in the Los Angeles area where ambient air pollution levels are among the highest in the US and also prone to wildfire exposure and we will assess any changes of type 2 diabetes-related metabolic outcomes. This would be the longest-duration residential intervention trial, providing an opportunity to observe chronic changes in health outcomes. We plan to use a low-cost HEPA filtration device in this trial. If the intervention is proven to be beneficial, affordable residential use of air purifiers will be recommended as a practical means to reduce air pollution-induced risk for diabetes.

2/10/23 – Recruitment is now starting with the first batch of participants. A new pilot study has also been funded by the Southern California Environmental Health Science Center to conduct continuous glucose monitoring (CGS) in this UL study.

Principal Investigators: Dr. Zhanghua Chen (Department of Preventive Medicine, Keck School of Medicine, University of Southern California) & Dr. Jim Zhang (Department of Global & Environmental Health, Duke University) 

Funded by the Underwriters Laboratories, LLC.

Registered under (Identifier: NCT05718245

Check out our latest study updates!

Related Publications

  1. Cui X, Li F, Xiang J, et al. Cardiopulmonary effects of overnight indoor air filtration in healthy non-smoking adults: A double-blind randomized crossover study. Environ Int. 2018;114:27-36.
  2. Sinharay R, Gong J, Barratt B, et al. Respiratory and cardiovascular responses to walking down a traffic-polluted road compared with walking in a traffic-free area in participants aged 60 years and older with chronic lung or heart disease and age-matched healthy controls: a randomised, crossover study. Lancet. 2018;391(10118):339-349.
  3. Day DB, Xiang J, Mo J, et al. Association of Ozone Exposure With Cardiorespiratory Pathophysiologic Mechanisms in Healthy Adults. JAMA Intern Med. 2017;177(9):1344-1353.
  4. Morishita M, Adar SD, D’Souza J, et al. Effect of Portable Air Filtration Systems on Personal Exposure to Fine Particulate Matter and Blood Pressure Among Residents in a Low-Income Senior Facility: A Randomized Clinical Trial. JAMA Intern Med. 2018;178(10):1350-1357.
  5. Jiang SY, Ma A, Ramachandran S. Negative Air Ions and Their Effects on Human Health and Air Quality Improvement. International journal of molecular sciences. 2018;19(10).
  6. Cui X, Li Z, Teng Y, et al. Association Between Bedroom Particulate Matter Filtration and Changes in Airway Pathophysiology in Children With Asthma. JAMA Pediatr. 2020.
  7. Barkjohn KK, Norris C, Cui X, et al. Real-time measurements of PM2.5 and ozone to assess the effectiveness of residential indoor air filtration in Shanghai homes. Indoor Air. 2020.
  8. Singer BC, Delp WW, Black DR, IS W. Measured performance of filtration and ventilation systems for fine and ultrafine particles and ozone in an unoccupied modern California house. Available at Accessed on August 29th 2020. https://wwwostigov/servlets/purl/1375633. 2016;Supported by the U.S.  Department of  Energy under Lawrence  Berkeley National Laboratory Contract.
  9. Azimi P, Zhao D, Stephens B. Modeling the impact of residential HVAC filtration on indoor particles of outdoor origin (RP-1691). Science and Technology for the Built Environment. 2016;22(4):431-462.

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