Children with more green space near their homes have significantly stronger bones, a study has found, potentially leading to lifelong health benefits.
The scientists found that the children who lived in places with 20-25% more natural surface area had greater bone strength equivalent to half a year’s natural growth.
The study, the first of its kind, also found that the risk of very low bone density for these children was about 65% lower.
Bone strength increases in childhood and adolescence, before remaining stable until about age 50 and then declining. Increasing the size and accessibility of green spaces for children could therefore prevent fractures and osteoporosis in the elderly, the researchers said.
The link between green spaces and stronger bones is likely due to higher levels of physical activity in children living near parks, as this stimulates bone growth. The link was strongest for green spaces with trees, which the scientists said may be because these were more attractive places to visit.
“The stronger the bone mass is during childhood, the more capacity you have for later in life,” says Prof. Tim Nawrot of Hasselt University in Belgium, who was part of the research team with Dr. Hanne Sleurs and others. “So the real public health message from this study is that urban planners can build stronger bones in children, and that has long-lasting consequences.”
Previous research has shown that greater access to green spaces increases physical activity in children. Studies have found this too several benefits for children’s development, including a lower risk of obesity, lower blood pressure, higher IQs and better mentally And emotional well-being.
Green spaces are also linked to this better physically and mental health in adults. Woodland walks could save an estimated £185 million a year on mental health costs in the UK.
The study, published in the journal Environmental Healthfollowed more than 300 children in a region of Flanders, Belgium, that included urban, suburban, and rural areas.
The children’s bone density was measured using ultrasound at the ages of four to six years. The child’s age, weight, height, ethnicity and mother’s education level were taken into account.
For example, the results showed that children with 25% more green space within 1000 meters of their home had a 66% lower risk of very low bone density, i.e. they were in the lowest 10% of measurements. No difference was found between boys and girls in the study.
The researchers said the results were important because low bone growth early in life was as crucial to the development of osteoporosis as bone loss due to aging.
The team also tested whether screen time, vitamin supplements or daily consumption of dairy products affected the children’s results, but found no significant effects.
The study showed a strong link between nearby green space and bone strength in children, but was not designed to demonstrate a causal relationship. To do that, children would have to wear accelerometers to record their physical activity. “That wouldn’t be a very easy experiment to do,” Nawrot said.
Two recent studies examining bone density in adults and green spaces produced conflicting results. A analysis of 66,000 people in southwestern China found a significant positive association. But research among 4,000 people aged 65 and over in Hong Kong found no convincing link, possibly because Hong Kong is a very densely populated city with little green space.