The Northern California Study

Kaiser Permanente Northern California is an integrated health-care system that serves over 5 million people.  

We combined healthcare records from all 5 million Kaiser members in Northern California with satellite imagery data to determine how nature and greenery around member's homes may influence their annual healthcare costs. We did this because access to nature and "green-space" has been robustly linked to improved health across a wide range of outcomes, from physical activity and cardiovascular disease to mental health and longevity.

"Access to nature has been robustly linked to improved health..."

We found that individuals living in the greenest neighborhoods incurred, on average, $374 less per year in healthcare expenditures, than  their peers living in the least green neighborhoods - even after taking into account a wide number of personal (age, sex, race/ethnicity) and neighborhood (median income, education levels, population and housing density) characteristics.

study looked at greenery and healthcare costs for 5 million Kaiser Permanente members in Northern California

Effect was attributable to fewer ER visits and hospitalizations.

"We saw fewer ER visits and fewer hospitalizations for individuals living in greener areas," says study lead author Dr. Stephen Van Den Eeden, a research scientist at the Kaiser Permanente Northern California Division of Research.  

"While people who can afford to live in greener areas tend to be wealthier and healthier to begin with, we found that taking those things into account doesn't change our findings. We are  as confident of our findings as you can be for this type of study.”

Greening America just a little could save millions in healthcare costs

“Our study adds to the growing body of literature that has found living in greener areas is tied to beneficial short- and long-term health outcomes,” says study principal investigator and study co-author, Dr. Matthew  H. E. M. Browning, assistant professor in the Clemson University Department of Parks, Recreation and Tourism Management. “The mechanisms linking nature and health are very diverse, but in general nature can decrease stress, promote healthy behaviors, and improve air quality.”