Cardiovascular Impacts of E-cigarettes Among Older Adults

Tobacco smoking remains a leading cause of chronic disease, premature death, and healthcare costs in the United States. Older adults bear the greatest burden of smoking-related cardiovascular disease (CVD), which is the leading cause of smoking-related mortality. Yet this age group remains significantly underrepresented in tobacco research and is also the only age group not experiencing a decline in smoking prevalence. Hypertension, a key factor connecting smoking to myocardial infarction, stroke, and heart failure, is especially common among older adults who smoke. Although e-cigarettes (ECs) deliver nicotine without combustion and may expose users to fewer harmful toxicants, there is limited evidence on their cardiovascular effects in older adults with pre-existing, smoking-related disease. This R03 project directly addresses a high-priority research area by directly examining the comparative effects of smoking and EC use in humans. The study will employ a rigorous, randomized within-subject crossover design to compare cigarette smoking and exclusive EC use among 30 adults aged 50 and older with hypertension. Participants will complete two 14-day phases: (1) continued smoking and (2) use of an authorized EC product. Aim 1 will evaluate changes in laboratory-based cardiovascular health measures, including resting blood pressure and heart rate, across both conditions. Aim 2 will assess changes in real-world cardiovascular function through remote measurements of blood pressure, heart rate, heart rate variability, and heart rate per step-a novel composite indicator of cardiovascular efficiency. The findings from this study will clarify short-term mechanistic effects of EC switching on cardiovascular health and identify which outcomes and measurement methods are most sensitive to change. This work will provide the first prospective evidence linking laboratory and real-world measures of cardiovascular function in older adults with smoking-related disease, thereby enhancing understanding of the health impacts of EC in populations at the greatest risk for CVD.

• Nicotine E-cigarette (Other): E-cigarettes that are FDA-authorized will be provided to participants in their preferred flavor (tobacco or menthol) and strength.
• Tobacco Cigarette (Other): Participants own brand cigarette

Primary outcomes

• Heart Rate (laboratory) [Session 1 (baseline), Session 2 after 14 days of product use (smoked cigarettes or e-cigarettes counterbalanced), Session 3 after 14 additional days of product use (smoked cigarettes or e-cigarettes counterbalanced)]: Resting heart rate, in beats per minute, will be measured in the research laboratory. Averaged readings will be used.
• Blood Pressure (laboratory) [Session 1 (baseline), Session 2 after 14 days of product use (smoked cigarettes or e-cigarettes counterbalanced), Session 3 after 14 additional days of product use (smoked cigarettes or e-cigarettes counterbalanced)]: Blood pressure, in mmHg, will be measured in the laboratory (systolic and diastolic). Averaged readings will be used.
• Blood Pressure (remote monitoring) [Collected daily during each of two 14-day product-use periods: one involving cigarette smoking and the other involving e-cigarette use.]: Averaged at-home blood pressure readings (systolic and diastolic)
• Daily Resting Heart Rate (remote monitoring) [Collected continuously across 14 days for each condition (smoking and e-cigarette)]: Daily average derived from wrist-worn wearable activity tracker. Calculated by dividing daily average heart rate, measured in beats per minute, by the total daily step count recorded by a study-provided wearable device.
• Daily Heart Rate Variability (remote monitoring) [Collected continuously across 14 days for each condition (smoking and e-cigarette)]: Daily average derived from wrist-worn wearable activity tracker
• Daily Heart Rate per Step [Daily throughout each of two 14-day product-use periods, approximately study Days 1-28.]: Daily resting heart rate, in beats per minute, will be obtained using a study-provided wearable device. Repeated daily measurements will be compared within participants between the cigarette-smoking and e-cigarette periods.

Sex: All, ages: 50 Years to any

Inclusion Criteria:

* Age 50 years or older.
* Currently smokes 5 or more combustible tobacco cigarettes per day and has smoked at this level for at least 1 year, based on self-report.
* Expired-air carbon monoxide level ≥8 parts per million (ppm), confirming recent cigarette smoking.
* Average screening/baseline systolic blood pressure ≥130 mm Hg or average screening diastolic blood pressure ≥80 mm Hg.
* Able and willing to provide informed consent and complete the study procedures, including in-person visits, two 14-day study periods, daily check-ins, and use of study equipment.
* If able to become pregnant (confirmed with participant), agree to avoid pregnancy during the study.

Exclusion Criteria:

* Self-reported consumption of 4 or more standard alcoholic drinks for women or 5 or more for men on any single day during the past 30 days.

Self-reported daily nonmedical use of opioids, stimulants, sedatives, cannabis, or another substance.

* Currently seeking or receiving smoking-cessation treatment.
* Currently uses another tobacco or nicotine product (e.g., electronic cigarettes or smokeless tobacco) on 2 or more consecutive days during the past month.
* Currently taking medication for the treatment of hypertension.
* Experienced a major medical event, including a cardiovascular event, within the past 6 months, such as myocardial infarction or acute coronary syndrome, stroke or transient ischemic attack, coronary or peripheral revascularization, hospitalization for heart failure.
* A current unstable cardiovascular condition that, in the judgment of the PI or designated medical clinician, would make participation unsafe.
* Confirmed severe hypertension at screening: resting systolic blood pressure greater than 180 mm Hg OR diastolic blood pressure greater than 120 mm Hg on repeat assessment.
* Pregnancy, as indicated by a positive screening urine pregnancy test conducted for a participant who reports being able to become pregnant.
* The investigator or medical monitor determines that participation would present an unacceptable medical or safety risk (i.e., current concerning cardiovascular or neurologic symptoms; an acute or uncontrolled medical illness; clinically significant intoxication or withdrawal; a medication or health change likely to make blood pressure, heart rate, or study participation unsafe; inability to safely use the study equipment despite training; or another specific condition that creates a foreseeable risk from continued smoking, e-cigarette exposure, or study procedures)

NIH grants: R03HL188068