Effects of Noise and Public Setting on Blood Pressure Readings

BACKGROUND: Guidelines emphasize quiet settings for blood pressure (BP) measurement. OBJECTIVE: To determine the effect of noise and public environment on BP readings. DESIGN: Randomized crossover trial of adults in Baltimore, Maryland. (ClinicalTrials.gov: NCT05394376). SETTING: Study measures were obtained in a clinical research office and a public food market near Johns Hopkins University School of Medicine in Baltimore, Maryland. PARTICIPANTS: 108 community-dwelling adults from the Baltimore, Maryland, area recruited through measurement-screening campaigns, mailings to previous study participants, and referrals from hypertension clinics. INTERVENTION: Participants were randomly assigned to the order in which they had triplicate BP measurements in each of 3 settings: 1) private quiet office (private quiet [reference]); 2) noisy public space (public loud); and 3) noisy public space plus earplugs (public quiet). MEASUREMENTS: Differences in mean BP readings obtained in public loud and public quiet versus private quiet, overall and stratified by baseline systolic BP (SBP), age, and recent health care utilization. RESULTS: Of the 108 randomly assigned participants, mean age was 56 years (SD, 17), 84% were self-reported Black, 41% were female, and 45% had an SBP of 130 mm Hg or more. The average noise level in public loud was 74 dB and in private quiet was 37 dB. Mean SBPs were: 128.9 mm Hg (SD, 22.3) in private quiet, 128.3 mm Hg (SD, 21.7) in public loud, and 129.0 mm Hg (SD, 22.2) in public quiet. Corresponding diastolic BPs (DBPs) were 74.2 mm Hg (SD, 11.4), 75.9 mm Hg (SD, 11.6), and 75.7 mm Hg (SD, 12.0), respectively. Public-loud and public-quiet BPs had minimal, non-clinically important differences from private quiet BPs: public loud: ΔSBP, -0.66 mm Hg (95% CI, -2.25 to 0.93 mm Hg) and ΔDBP, 1.65 mm Hg (CI, 0.77 to 2.54 mm Hg); public quiet: ΔSBP, 0.09 mm Hg (-1.53 to 1.72 mm Hg) and ΔDBP, 1.45 mm Hg (0.64 to 2.27 mm Hg). The patterns were generally consistent across subgroups. LIMITATIONS: Single-center trial. Imbalance in the numbers and characteristics across the randomly assigned groups. CONCLUSION: The BP readings obtained in public spaces were minimally different from BPs obtained in a private office, suggesting that public spaces are reasonable settings to screen for hypertension. PRIMARY FUNDING SOURCE: Resolve to Save Lives.