Your local park could hold the fountain of youth – Expert Reaction

Having green spaces like parks and community gardens in your neighbourhood could be associated with slower biological aging, new international research suggests.

The long-term study involved more than 900 people in the US. Researchers found people with more green space around them were likely to see their epigenetics (the way our DNA is organised and regulated) degrade slower, which can reduce the symptoms of aging. The US and Spanish author team also found that the link between epigenetic aging and green spaces was even stronger in people from disadvantaged neighbourhoods.

The SMC asked local experts to comment on the research.

Dr Mirjam Schindler, Lecturer in Human Geography, Victoria University of Wellington, comments:

“The study by Kim and co-authors suggests that living near green spaces may lead to slower epigenetic aging, which has significant implications for future housing strategies in New Zealand cities. As an expert in urban green spaces in Aotearoa and overseas, I am thrilled to see further evidence quantifying the benefits provided by green spaces and their pivotal role in creating healthy living environments.

“This study provides valuable insights that urban planners and decision-makers need to take note of, especially in the ongoing discussions on housing strategies. The study reinforces the urgency of creating ample, high-quality green spaces that meet residents’ needs, ensuring their accessibility and the subsequent reaping of benefits. Close proximity to green spaces is key to unlocking their health effects, including the potential to slow epigenetic aging.

“Additionally, the study confirms existing disparities in access to green spaces and their associated benefits among different population groups, including various ethnicities and age groups. Similar disparities have been observed in previous green space research in New Zealand and internationally. The study underscores the role of our living environment, including green spaces near our homes, as a significant determinant of our health. Therefore, it is crucial that future housing strategies in New Zealand cities prioritise the conservation and expansion of urban green spaces, aiming to bridge the gap in access and make them available to all. Ensuring easy accessibility to nearby green spaces, regardless of socioeconomic status, has the potential to address health disparities. This necessitates thoughtful planning and strategic distribution of green spaces throughout our cities, considering factors such as population density and neighborhood demographics.

“The study’s findings highlight the importance of green spaces for promoting healthy living environments and the need to prioritise their conservation and integration in future housing strategies for our Aotearoa cities.”

No conflict of interest declared.

The SMC Spain also gathered expert comments:

Prof Manuel Franco, epidemiologist, professor and researcher at the Universities of Alcalá and Johns Hopkins. Spokesman for the Spanish Society of Public Health and Health Administration SESPAS, he says:

“This is a very well designed study within a powerful and classic cardiovascular cohort study carried out in different US cities that answers a key question for the health of all those people living in cities today: is long-term exposure to urban green spaces associated with epigenetic ageing? Does the low socioeconomic status of the neighbourhood modify that effect? The results showed that the higher the exposure to green spaces, the lower the epigenetic ageing.

“Therefore, we have more and better scientific evidence to increase and promote the use of urban green spaces and that these serve to slow down the epigenetic ageing process, which would help reduce the incidence of chronic diseases and improve the quality of life and life expectancy.

“The authors highlight in their conclusions how these findings support policies to promote equity, the use of green spaces by the whole population, and increase their health benefits.

“Research on the use of parks involves understanding the processes of gentrification and inequalities in their use. This is something we have already studied in Madrid.

“This study has been carried out in the USA, with a society that uses parks less than Spanish society. In this sense, and now that the heat is coming, the use of parks as resources that promote and protect the health of citizens is fundamental”.

He declares that he has no conflicts of interest.

Dr Usama Bilal, Urban Epidemiologist, Assistant Professor of Epidemiology in the Department of Epidemiology and Biostatistics and the Urban Health Collaborative in the School of Public Health at Drexel University in Philadelphia (USA), says: 

“The CARDIA study, on which these data are based, is a very high quality cardiovascular study. It is one of the few studies where we can follow people over a long period of time with information about their place of residence, greenery and parks, etc. It seems that the methods and measures are adequate. These kinds of observational studies always have a number of underlying limitations that are difficult to cover, but I think the authors have done a good job with these limitations and, more importantly, they have a very unique data set (20-year residential history and epigenetics). I think it is a very novel study.

“The work is very consistent with the existing evidence that green space is important for our health. It is also consistent with the idea that green space is even more important for low-income people, a phenomenon we call the ‘equigenetic hypothesis’, the main idea being that parks are especially beneficial for low-income people.

“We can’t assign causality [based] on these results, but they point us to some important ideas about how green space might influence our health. It continues to confirm something we have been observing for a long time: green spaces are important for health. This study is more methodologically refined, measuring a much more proximal outcome variable (epigenetic affect).

“I don’t see why the results could not be extrapolated to Spain. The important thing is that these studies on greenness are usually quite sensitive to the climate of each area (because the basal greenness varies a lot based on the climate of each area, of course: Asturias is different from Almeria. In this case they use four very different cities: Oakland in California as a more temperate area with a climate similar to the Mediterranean, Chicago and Minneapolis as areas with cold winters, and Birmingham, Alabama as a much warmer and more humid subtropical area”.

He declares no conflicts of interest.