Living near gardens, parks and green spaces could increase bone density and reduce the risk of osteoporosis. This is the hypothesis put forward by research published online in Annals of the Rheumatic Diseases according to which lower pollution levels and the incentive to move more outdoors can represent protective factors for bones.
Data from the UK Biobank
Osteoporosis weakens bones, making them brittle and prone to fractures. It can cause chronic pain, reduced mobility and a deterioration in quality of life. Among other things, its global prevalence is expected to increase with the rapid aging of the population and changes in lifestyle.
Osteoporosis is caused by genetic, hormonal and environmental factors and the researchers focused on the latter by analyzing the data contained in the United Kingdom Biobank which collects genetic and health data from 500,000 voluntary participants. Specifically, the researchers analyzed data from 400,000 people, with an average age of 56, just over half of whom (53%) were women.
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Measuring the risk of osteoporosis
For all patients, information on their bone mineral density and potentially influential factors including ethnicity, annual household income, education level, employment, residential area, alcohol consumption, physical activity levels, smoking status and diet was recorded. Their genetic risk of osteoporosis was calculated using a polygenic risk score and a widely used measure, called the Normalized Vegetation Difference Index (NDVI).
The measurement of greenery and exposure to pollutants
The Normalized Vegetation Difference Index is the main satellite indicator of the presence of vegetation on the Earth’s surface and its evolution over time. This indicator was used to determine the amount of green space in the residential area of the study participants. We also examined average annual exposures to the pollutants nitrogen oxide (NO2) and PM2.5 particulate matter estimated by residential postcode and data from the Escape project examining the long-term human health effects of exposure. to air pollution in Europe.
The greener, the more bone density
During an average monitoring period of 12 years, new cases of osteoporosis were diagnosed in 9,307 people, especially among the older, female, smokers and retired people with a lower level of education and more economically disadvantaged conditions. But a constant association also emerged between the amount of green space and new cases of osteoporosis. The authors measured the NDVI around people’s homes starting from 300 meters up to a maximum of 1500 meters. The greener the area around the residence, the higher the bone mineral density observed in the people, and they also observed a 5% lower risk of developing osteoporosis.
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Because pollution impacts bones
But what does osteoporosis have to do with pollution? The key factors taken into consideration by researchers to explain the reduction in the risk of developing osteoporosis are lower levels of nitric oxide and Pm 2.5. Several studies have shown that exposure to air pollution can produce oxidative stress, inflammation and alter hormones, thus increasing the risk of osteoporosis. People who live in greener areas are exposed to less risk because trees and plants act as natural filters, removing pollutants from the air. The fact that living in areas with green spaces offers more opportunities to exercise outdoors, thus promoting the synthesis of vitamin D, which is precious for bones, also plays a role.
Prevention that comes from nature
Even if it is an observational study which among other things takes into consideration people who are generally in good health and therefore not entirely representative of the general population, these results are important for prevention: “This is the first evidence that indicates that green residential is associated with increased bone density and a reduced risk of developing osteoporosis,” he explained Zhengxiao Ouyang from Central South University in China and lead author of the study. “These findings provide valuable insights into the potential of greenery in preventing the onset of osteoporosis and highlight the importance of urban greenery in developing effective prevention strategies.”