Indoor air filtration reduces blood pressure in older people

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Takeaway

  • Systolic BP dropped significantly among residents of a senior facility that used portable air filtration systems for 3 days.

Why this matters

  • These inexpensive systems filter out fine particulate matter, which is a risk factor for cardiovascular disease and mortality.

Key results

  • As would be expected, real air filtration reduced small particulates in the air much more than sham filtration.
  • Compared with sham, filtration for 3 days (BP in mmHg) decreased:
    • Systolic BP: 3.2 (95% CI, −6.1 to −0.2).
    • Diastolic BP: 1.5 (95% CI, −3.3 to 0.2).
  • Low efficiency filtration reduced:
    • Systolic BP: 3.4 (95% CI, −6.8 to −0.1).
    • Diastolic BP: 2.2 (95% CI, −4.2 to −0.3).
  • High-efficiency filtration reduced:
    • Systolic  BP: 2.9 (95% CI, −6.2 to 0.5).
    • Diastolic BP: 0.8 (95% CI, −2.8 to 1.2).
  • A post-hoc analysis of patients with obesity found even steeper decreases with filtered vs unfiltered air:
    • Systolic: −7.5 (95% CI, −12.0 to −3.1).
    • Diastolic: −2.9 (95% CI, −5.6 to −0.2).

Study design

  • Randomized, double-blind crossover trial, 40 people living in a Michigan facility for older adults.
  • Outcome: BP.
  • Funding: National Institute of Nursing Research.

Limitations  

  • Small population.
  • Probably not powered to detect clear differences between low/high-efficiency systems.