Abstract Body (Do not enter title and authors here): Introduction/Background
The impact of exposure to air pollution (AP) in the home on cardiovascular health is limited because most data is based on outdoor exposure. This is an important data gap because in the United States people spend approximately 90% of their time indoors. This study quantifies home exposure to AP and examines its association with various indicators of cardiovascular health.
Research Questions/Hypothesis
The hypothesis being tested is that increased exposure to AP in the home is associated with increased heart rate (HR), mean arterial pressure (MAP), and central and brachial blood pressure (BP) in older adults.
Methods/Approach
The Household Air Pollution Study (HAPS) is an ongoing prospective cohort (n=100) of adults age ≥ 60 years in New Orleans, Louisiana, examining the association between exposure to particulate matter ≤ 2.5 mg/m-cubed (PM_2.5), black carbon (BC), and nitrogen dioxide (NO₂) in the home on various indicators of heart health. Pollutant concentrations are measured in the home at two time points, baseline and 6 months. Each sampling period is 7 consecutive days. Outcomes are measured every other day (n=4) during each sampling period. Central and brachial BP, HR, MAP are measured three times at each home visit using a SphygmoCor XCEL. Outcomes are averaged for each sampling period. Unadjusted generalized estimating equation models with a Gamma distribution and log link are used to account for the repeated measures and the non-normal distributions of the air pollutants. PM_2.5, BC, and NO₂ are modelled separately, and treated as continuous variables.
Results/Data (descriptive and inferential statistics)
This preliminary analysis includes 93 participants. The median age of participants is 71.5 years; baseline median BC is 0.626 µg/m-cubed, PM_2.5 is 5.283 µg/m-cubed, and NO₂ is 6.79 ppb. Higher concentrations of PM_2.5 and BC is positively associated with HR: A 10-unit increase in PM_2.5 is associated with a 1.01 unit increase in mean HR (p-value=0.0003), and a 10-unit increase in BC results in a 1.05 unit increase in HR (p-value=0.0016). There were no associations between PM_2.5, BC, or NO₂ and the other outcomes.
Conclusion
These preliminary results suggest that exposure to low levels of indoor PM_2.5 and BC in the home may contribute to increased mean HR in older adults. Additional studies are needed to further explore these findings.