J Epidemiol Community Health 62:647-649 doi:10.1136/jech.2007.071894
  • Short report

Children living in areas with more street trees have lower prevalence of asthma

  1. G S Lovasi1,
  2. J W Quinn1,
  3. K M Neckerman1,
  4. M S Perzanowski2,
  5. A Rundle3
  1. 1
    Institute for Social and Economic Research and Policy
  2. 2
    Department of Environmental Health Sciences, Mailman School of Public Health
  3. 3
    Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA
  1. Dr G S Lovasi, 820 IAB, MC 3355, 420 W 118th St, New York, NY 10027, USA; gl2225{at}
  • Accepted 25 February 2008
  • Published Online First 1 May 2008


Background: The prevalence of childhood asthma in the USA increased by 50% from 1980 to 2000, with especially high prevalence in poor urban communities.

Methods: Data on the prevalence of asthma among children aged 4–5 years and on hospitalisations for asthma among children less than 15 years old were available for 42 health service catchment areas within New York City. Street tree counts were provided by the New York City Department of Parks and Recreation. The proximity to pollution sources, sociodemographic characteristics and population density for each area were also measured.

Results: Controlling for potential confounders, an increase in tree density of 1 standard deviation (SD, 343 trees/km2) was associated with a lower prevalence of asthma (RR, 0.71 per SD of tree density; 95% CI, 0.64 to 0.79), but not with hospitalisations for asthma (RR, 0.89 per SD of tree density; 95% CI, 0.75 to 1.06).

Conclusions: Street trees were associated with a lower prevalence of early childhood asthma. This study does not permit inference that trees are causally related to asthma at the individual level. The PlaNYC sustainability initiative, which includes a commitment to plant one million trees by the year 2017, offers an opportunity for a large prospective evaluation.


  • Funding: This work was funded by the National Institute for Environmental Health Science (R01-ES014229) and the Robert Wood Johnson Foundation’s Health & Society Scholars Program.

  • Competing interests: None.

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