Air Pollution and Cardiovascular Disease in Qatar: an Interventional Study to Reduce Blood Pressure

Chronic cardio-metabolic diseases such as hypertension and diabetes contribute disproportionately to global morbidity and mortality and are increasing believed to have multiple environmental influences.

PM2.5 is the fifth leading risk factor for global mortality - largely due to cardiovascular disease (CVD). Reducing personal exposure to air pollution has shown promise in improving key cardiovascular risk factors (blood pressure and insulin resistance) in limited studies, but durability of these effects is not known. Personal air cleaners have been shown to decrease personal exposure to PM2.5 and reduce blood pressure in small studies and may serve as a pragmatic intervention in high-risk patients in whom air pollution is a strong contributor to cardiovascular health.

Inclusion criteria

• Non-smokers (100% abstinence from use of any smoking or vaping product during the prior year)
• Age ≥18 and less than 60 years old
• Living in a single residence (home, apartment) located anywhere in Qatar
• Mild systolic hypertension: screening visit systolic BP 130 to 159 mm Hg (off treatment or taking ≤ 2 BP medications that have been stable without changes during prior 4 weeks) plus ≥ 2 more additional criteria for the metabolic syndrome:

• Waist circumference ≥102 cm if male and ≥88 cm if female
• Fasting triglycerides ≥150 mg/dL (or taking a triglyceride-lowering medication)
• HDL-C ≤ 40 mg/dL if male and ≤ 50 mg/dL if female (or taking an HDL-raising medication),
• Fasting glucose ≥100 mg/dL

Exclusion criteria

• Pregnancy (self-reported)
• Screening visit urine positive for cotinine (NicAlert >100 ng/mL)
• Living with an active smoker who smokes indoors (by self-report)
• High risk conditions that prohibit allowing home BP to be >130/80 mm Hg during the10-week trial including any cardiovascular disease (coronary artery disease, prior stroke, heart failure, peripheral arterial disease, aneurysm) or ≥ stage 3 kidney disease (estimated glomerular filtration rate < 60 ml/min)
• A medical condition placing the participant at risk from participation (per investigators)
• Expected overnight travel outside their residence during the study
• HEPA filter within the air conditioners of the residence (self-reported) or individual use of HEPA filter
• Unable to comprehend/sign an informed consent
• Lung disease requiring oxygen
• Cancer receiving treatment
• Screening visit: BP ≥160/100 mm Hg or fasting blood glucose ≥126 mg/dL and confirmed diabetes with follow-up HbA1c ≥6.5%. If glucose is elevated ≥126 mg/dL but HbA1c<6.5%, they could still participate.
• Medication changes in past 4 weeks. If participants are on medications for high BP or hyperlipidemia, they will need to have had stable therapy during prior 10 weeks with no planned changes during the study
• Left upper arm circumference >17 inches as this will make BP levels inaccurate with the home monitor used
• Acute illness or infectious symptoms within the prior 4 weeks.