Greenness/green spaces & health effects: The state of the art (i.e., what do we know?)

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1 Greenness/green spaces & health effects: The state of the art (i.e., what do we know?) Dr Elizabeth Richardson PhD European Research Council-funded researcher Centre for Research on Environment, Society and Health (CRESH) University of Edinburgh, UK

2 Background Green is good, right? Common sense? More evidence needed? More discussion needed?

3 Outline Background to green space and health research What s the evidence? How? Potential causal pathways Is the relationship the same for everyone? Research strengths and weaknesses

4 Green space and health research

5 How researched? Is the health of individuals/populations related to the greenness/green space they experience? Greenness/ Green space? Health

6 What do we mean by green space? OPEN SPACE City square NATURAL SPACE GREEN SPACE Public park Snow and ice Bare rock Private garden

7 Statistical analysis Is green space independently related to health? i.e., does the relationship remain afterwe account for other factors? age, sex, affluence, ethnicity, smoking, socioeconomic status (individual and area) e.g., greener house prices wealthier residents?

8 Evidence for the relationship

9 Green space and mental health (NZ) Odds Ratio Higher risk Lower risk Poor mental health (SF-36) Poor mental health ( SF36 ), New Zealand (Richardson et al. 2013) 19% (least) (most) greener Green space availability quartile

10 Are greener places healthier? Health outcome All-cause mortality Cardiovascular disease mortality Respiratory disease mortality Lower mortality risk No change in risk England Canada USA Japan France England UK(men) Canada USA UK (men) Canada UK(women) New Zealand Lithuania UK (women) Sources: Coutts et al 2010; Gascon et al2016 (systematic review); Harlan et al 2013; Hu et al. 2008;Kihal-Talantikite et al 2013; Mitchell and Popham 2008; Richardson and Mitchell 2010; Richardson et al. 2010; Takano et al. 2002; Tamosiunas et al 2014; Uejio et al 2011; Villeneuve et al. 2012; Wilker et al

11 Are greener places healthier? Health outcome Lower risk No change in risk Overweight/obesity 8 European cities, US, Spain, Canada, Australia (women) New Zealand, Canada, Egypt, Australia (men) Cardiovascular diseases Netherlands New Zealand Respiratory diseases Low birth weight Poor general health Poor physical health Poor mental health Netherlands Spain, US, England (whitebritish), Germany, Israel, Canada England (not low income suburban) Netherlands, Denmark, Spain Australia New Zealand, Netherlands, Denmark, Australia, Spain, US, UK,Lithuania, Chile, Germany Spain, England (Pakistani origin) New Zealand Wales, Canada, Sweden Sources: Agay Shay et al 2014; Alcock et al 2015; Amoly et al 2014; Annerstedt et al. 2012; Araya et al 2007; Astell-Burt et al 2013, 2014; Balseviciene et al 2014; Bell et al. 2008; Beyer et al 2014; Cummins and Fagg 2012; Dadvand et al. 2012, 2014, 2016; de Vries etal. 2003, 2013; Donovan et al. 2011; Ellaway et al 2005; Flouriet al 2014; Fuertes et al 2014; Huynh et al. 2013; Hystad et al 2014; Liu et al 2007; Lovasi et al 2013; Maas et al. 2006, 2009; Markevych et al 2013; McEachan et al 2015; Mitchell and Popham 2007; Mofawi et al 2012; Nutsford et al 2013; Potestio et al. 2009; Prince et al 2011; Reklaitiene et al 2014; Richardson et al. 2013; Roe et al 2013; Sarkar et al 2013; Stigsdotter et al. 2010; Sturm et al 2014; Sugiyama et al. 2008; Triguero-Mas et al 2015; White et al 2013.

12 Are these studies biased? Cross-sectional: one point in time. Correlational: no causal inference Selection bias: healthier people choose neighbourhoods that are healthier for them. Longitudinal studies? Improved mental health for those who move to greener locations (Alcock et al 2015: opengreen; White et al 2013; Annerstedt et al 2015: serene nature) Higher birth weight for mothers who had accumulated more green space exposure over life course (Scotland, unpublished)

13 Conclusion I Greener places are often healthier places

14 Conclusion I Greener places are often healthier places* ** * CAVEAT 1: Relationships vary by individual characteristics & context. ** CAVEAT 2: There are important exceptions

15 Important exceptions and lessons Increased obesity riskin greener neighbourhoods (Cummins and Fagg 2012 in England, and Prince et al 2011 in Canada (men only)) Higher male mortality rates in greener US cities (Richardson et al 2012) CVD risk lower in neighbourhoods with high variability in greenness compared with predominantly green or non-green areas (Pereira et al 2012, Australia) WHY? Variability in greenness = Mixed green and non-green land use = health promoting = aesthetically-pleasing natural environment + access to urban destinations In some contexts the greenest locations are by-products of urban sprawl Green space isn t detrimental to health per se But: Implications for urban planning for population health.

16 How? Potential causal pathways

17 Potential causal pathways Green space Possible pathways:? Health 1. Opportunities for physical activity 2. Facilitation of social contacts 3. Stress reduction 4. Psychological restoration 5. Reduce environmental exposures (noise, air pollution, heat) How to test?

18 How do we test potential pathways? Green space? Health Green space Potential pathway Health (a) Pathway does not explain relationship: Potential Green space pathway (b) Pathway partly explains relationship: Potential Green space pathway (c) Pathway fully explains relationship: Potential Green space pathway Health Health Health

19 1. Physical Activity Physical activity: Physical health benefits Mental health benefits Green spaces: opportunities for walking, cycling, playing for recreation and transportation.

20 More physical activity in greener places? YES: Denmark, France, Wales, England, Europe, Australia, US, New Zealand. Sources: Almanza et al 2012; Cerin et al. 2008; Chaix et al 2014; Cohen et al. 2007; Coombes et al. 2010; Ellaway et al. 2005; Grigsby-Toussaint et al 2011; Karusisi et al 2012; Lachowycz et al 2012; Lachowycz and Jones 2014; Maas et al. 2009; Mytton et al 2012; Richardson et al. 2013; Roemmich et al. 2006; Sugiyama et al. 2008; Tilt et al 2007; Toftager et al Does person meet recommended level of physical activity? (Richardson et al. 2013) 1.60 More likely Odds Ratio (least) (most) greener Green space availability quartile NO: Netherlands, Scotland, England, New Zealand, Canada, Spain. Sources: Foster et al. 2009; Hillsdon et al. 2006; Maas et al. 2008; Ord et al 2013; Prince et al 2011; Tilt et al 2007; Triguero-Mas et al 2015; Witten et al

21 Does physical activity explain the relationship? Higher risk Green space and mental health in New Zealand (Richardson et al. 2013) basic adjusted model + physical activity Odds Ratio Lower risk (least) (most) greener Green space availability quartile

22 Does physical activity explain the relationships? Health outcome General health Mental health Physical health Not at all Partially Fully Cycle commuting (NL) Total PA (NL) Total PA (NL) Recreational walking (England) Outdoor leisure/transport PA(NL) Total PA (Spain) Total PA (NZ, England) Outdoor leisure/transport PA(NL) Recreational walking (AUS) Recreational walking (AUS) Sources: Dadvand et al. 2016;de Vries et al. 2013; Lachowycz and Jones 2014; McEachan et al2015; Maas et al. 2008; Richardson et al. 2013; Sugiyama et al

23 Just add green space?? Sugiyama et al. 2013: Adelaide, longitudinal Green spaces were related to maintaining recreational walking Green spaces were not related to starting recreational walking

24 2. Social contacts Social contacts Social support and cohesion Sense of community Acceptance, belonging Health benefits General and mental health Reduced mortality risk Do green spaces facilitate social contact?

25 Stronger social contacts in greener places? More green space: Greater social cohesion and belonging Fewer feelings of loneliness and lack of social support Better quality green space: Greater social cohesion and belonging Greater sense of community Sources: Maas et al. 2009; de Vries et al. 2013; Kuo et al. 1998; Francis et al

26 Do social contacts explain the relationship? Health outcome General health Not at all Partially Fully - Feelings of loneliness (NL) Social support (NL, Spain) Social cohesion (NL) - Mental health Local social interaction (AUS) Social support (AUS) Feelings of loneliness (NL) Social support (NL) Social cohesion (NL) Social coherence score (AUS) - Physical health Social coherence score (AUS) - Sources: Dadvand et al. 2016;Maas et al. 2009; de Vries et al. 2013; Sugiyama et al. 2008;Francis et al

27 3. Stress reduction Ulrich s (1983) Psychoevolutionary Theory Evolutionary basis: open natural spaces were beneficial for our survival beneficial physiological responses Haluza et al (2014) review (n=17 experimental trials): generally significant beneficial effects on blood pressure, heart rate, endocrine and immune systems Evidence of longer-term associations (population studies): greenness and lower BP in children (Markevych et al. 2014) green space and lower stress (cortisol) (Roe et al 2013) green space buffers effects of stressful life events on health (van den Berg 2010)

28 4. Psychological restoration Attention Restoration Theory Kaplan and Kaplan (1989) Nature effortlessly holds our attention Trials: fatigued cognitive processes can recover after a demanding task, attention and emotion improved in nature but not urban setting (Hartig et al 2003) Children with ADHD had better attention after walk in park than walk in urban setting (Faber Taylor and Kuo 2008)

29 5. Reduce environmental exposures Theoretical pathways: Green spaces reduce air pollution and noise improved respiratory and cardiovascular health Trees cool air due to shading protect against heat stress Green spaces increase pollen aggravate allergies and asthma

30 Synergies: intertwined pathways =? PA in natural environments vs. other environments? Improved mental wellbeing (Pretty et al. 2005, Thompson Coon et al. 2011) Reduced risk of poor mental health (Mitchell 2013) Reduced blood pressure (Duncan et al. 2014)

31 Conclusion II Greener places may be healthier places because of: Physical activity Social contacts Stress reduction Psychological restoration Reduced environmental exposures All of the above* *relative contributions depend on health outcome, and characteristics of the individuals and contexts

32 Is the relationship the same for all?

33 Is the relationship the same for all? For whom do these relationships hold? Critical for planning population health interventions: Without this knowledge inappropriate design Health benefits might not be distributed equally

34 Gendered differences? Incidence Rate Ratio Higher risk Lower risk Respiratory disease mortality, UK Male Female (Richardson and Mitchell 2010) (11%) 0.80 < 25% 25 to <50% 50 to <75% 75%+ greener Green space availability

35 Green space quality differences Quality attributes: Well-maintained, clean Good facilities Aesthetically pleasing Safe Quality AND quantity related to general and mental health Poor quality green space might be detrimentalto health Mitchell and Popham 2007; de Vries et al. 2013; van Dillen et al. 2012, Francis et al

36 Demographic differences? Strongest relationships with local green space: Children Elderly Housewives Low SES individuals More dependent on local area Importance of life stage Sources: Maas et al. 2009; de Vries et al. 2003; Maas et al

37 Socioeconomic differences? Circulatory disease mortality, England (Mitchell and Popham 2008) income Lowest income group Higher risk >2x x1.5 greener (Also: Dadvand et al. 2012, low birth weight births)

38 Conclusion III Green places may be healthier for some population groups than others. Various characteristics of green spaces affect their health potential.

39 Research strengths and weaknesses STRENGTHS Large populations studied Generally consistent findings WEAKNESSES Cross-sectional studies: Causal inference not possible Selection bias (Natural) experiments or longitudinal designs needed. How to measure health-relevant contact with nature? What about non-residential spaces? (e.g., activity spaces) Improved measures of usage/exposure needed Not enough attention to how the relationships vary: Importance of type and quality of space Importance of different user groups

40 Implications Green space seems to be more than just a luxury and consequently the development of green space should be allocated a more central position in spatial planning policy. (Maas et al. 2006) Green space could be a powerful public health tool More evidence is needed: inform realistic expectations prevent unintended consequences

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