March 18 | 2019

Vegetation diversity protects against childhood asthma: results from a large New Zealand birth cohort.

Donovan GH, Gatziolis D, Longley I, Douwes J.

Nat Plants. 2018 Jun;4(6):358-364. DOI: 10.1038/s41477-018-0151-8


We assessed the association between the natural environment and asthma in 49,956 New Zealand children born in 1998 and followed up until 2016 using routinely collected data. Children who lived in greener areas, as measured by the normalized difference vegetation index, were less likely to be asthmatic: a 1 s.d. increase in normalized difference vegetation index was associated with a 6.0% (95% CI 1.9–9.9%) lower risk of asthma. Vegetation diversity was also protective: a 1 s.d. increase in the number of natural land-cover types in a child’s residential meshblock was associated with a 6.7% (95% CI 1.5–11.5%) lower risk. However, not all land-cover types were protective. A 1 s.d. increase in the area covered by gorse (Ulex europaeus) or exotic conifers, both non-native, low-biodiversity land-cover types, was associated with a 3.2% (95% CI 0.0–6.0%) and 4.2% (95% CI 0.9–7.5%) increased risk of asthma, respectively. The results suggest that exposure to greenness and vegetation diversity may be protective of asthma.

March 11 | 2019

Geospatial analyses of adverse birth outcomes in Southwestern Ontario: Examining the impact of environmental factors.

Jamie A. Seabrook, Alexandra Smith, Andrew F. Clark, Jason A. Gilliland

Environmental Research Volume 172, May 2019, Pages 18-26




A growing body of research has examined the association between exposure to environmental factors during pregnancy and adverse birth outcomes; however, many studies do not control for potential covariates and findings vary considerably.


To test the relative influence of environmental factors including exposure to air pollution, major roads, highways, industry, parks, greenspaces, and food retailers on low birth weight (LBW) and preterm birth (PTB) in Southwestern Ontario (SWO), Canada, while accounting for medical (e.g., previous preterm birth, gestational diabetes), behavioral (e.g., alcohol, smoking), demographic (e.g., maternal age, body mass index), and neighborhood-level socioeconomic (e.g., household income, education) factors.


This retrospective cohort study consisted of a large sample of pregnant women from SWO who gave birth to singleton newborns between February 2009 and February 2014 at London Health Sciences Centre. Data on maternal postal codes were entered into a Geographic Information System to map the distribution of maternal residences and determine selected characteristics of their neighborhood environments (i.e., socioeconomic, built, natural). These variables were developed based on postal codes where the mothers lived prior to giving birth. Logistic regression was used to assess the relative effects of the physical environment, socioeconomic status, clinical history, and behavioral risk factors on mothers having a LBW or PTB infant.


Out of 25,263 live births, 5.7% were LBW and 7.5% were PTB. Exposure to sulfur dioxide was a top predictor of both LBW and PTB. For every one-unit increase in sulfur dioxide, the odds of a LBW and PTB were 3.4 (95% CI: 2.2, 5.2) and 2.0 (95% CI: 1.4, 3.0) times higher, after controlling for other variables in the model, respectively (p < 0.001). Previous PTB was also highly associated with both birth outcomes.


Health care providers should be informed about the hazards of air pollution to developing fetuses so that recommendations can be made to their pregnant patients about limiting exposure when air quality is poor.

March 4 | 2019

The Lancet Commissions

The Global Syndemic of Obesity, Undernutrition, and Climate Change: The Lancet Commission report.

Prof Boyd A Swinburn MD, Vivica I Kraak PhD, Prof Steven Allender PhD, Vincent J Atkins, Phillip I Baker PhD, Jessica R Bogard PhD, Hannah Brinsden,  Alejandro Calvillo, Prof Olivier De Schutter PhD, Raji Devarajank, Prof Majid Ezzat FMedSci,  Prof Sharon Friel PhD, Shifalika Goenka PhD,  Ross A Hammond PhD, Prof Gerard  Hastings PhD, Prof Corinna Hawkes PhD, Mario Herrero PhD, Prof Peter S Hovmand PhD, …Prof William H Dietz MD.

The Lancet Volume 393, Issue 10173, 23 February–1 March 2019, Pages 791-846

Executive summary

Malnutrition in all its forms, including obesity, undernutrition, and other dietary risks, is the leading cause of poor health globally. In the near future, the health effects of climate change will considerably compound these health challenges. Climate change can be considered a pandemic because of its sweeping effects on the health of humans and the natural systems we depend on (ie, planetary health). These three pandemics—obesity, undernutrition, and climate change—represent The Global Syndemic that affects most people in every country and region worldwide. They constitute a syndemic, or synergy of epidemics, because they co-occur in time and place, interact with each other to produce complex sequelae, and share common underlying societal drivers. This Commission recommends comprehensive actions to address obesity within the context of The Global Syndemic, which represents the paramount health challenge for humans, the environment, and our planet in the 21st century.

February 25 | 2019

Spatiotemporal Variations in Ambient Ultrafine Particles and the Incidence of Childhood Asthma.

Lavigne E, Donelle J, Hatzopoulou M, Van Ryswyk K, van Donkelaar A, Martin R, Chen H, Stieb DM, Gasparrini A, Crighton E, Yasseen Iii AS, Burnett RT, Walker M, Weichenthal S.

Am J Respir Crit Care Med. 2019 Feb 20.. [Epub ahead of print]  DOI: 10.1164/rccm.201810-1976OC




Little is known regarding the impact of ambient ultrafine particles (<0.1 μm) (UFPs) on childhood asthma development.


To examine the association between prenatal and early postnatal life exposure to UFPs and development of childhood asthma.


A total of 160,641 singleton live births occurring in the City of Toronto, Canada between April 1st 2006 and March 31st 2012 were identified from a birth registry. Associations between exposure to ambient air pollutants and childhood asthma incidence (up to age 6) were estimated using random-effects Cox proportional hazards models, adjusting for personal- and neighborhood-level covariates. We investigated both single- and multi-pollutant models accounting for co-exposures to PM2.5 and NO2.


We identified 27,062 children with incident asthma diagnosis during the follow-up. In adjusted models, second trimester exposure to UFPs (Hazard Ratio (HR) per interquartile (IQR) increase = 1.09, 95% CI: 1.06 – 1.12) was associated with asthma incidence. In models additionally adjusted for PM2.5 and NO2, UFPs exposure during the second trimester of pregnancy remained positively associated with childhood asthma incidence (HR per IQR increase = 1.05, 95% CI: 1.01 – 1.09).


This is the first study to evaluate the association between perinatal exposure to UFPs and the incidence of childhood asthma. Exposure to UFPs during a critical period of lung development was linked to the onset of asthma in children, independent of PM2.5 and NO2.

February 19 | 2019

Health Benefits of Physical Activity Related to an Urban Riverside Regeneration.

Vert C, Nieuwenhuijsen M, Gascon M, Grellier J, Fleming LE, White MP, Rojas-Rueda D.

Int J Environ Res Public Health. 2019 Feb 5;16(3). pii: E462. Doi: 10.3390/ijerph16030462



The promotion of physical activity through better urban design is one pathway by which health and well-being improvements can be achieved. This study aimed to quantify health and health-related economic impacts associated with physical activity in an urban riverside park regeneration project in Barcelona, Spain. We used data from Barcelona local authorities and meta-analysis assessing physical activity and health outcomes to develop and apply the “Blue Active Tool”. We estimated park user health impacts in terms of all-cause mortality, morbidity (ischemic heart disease; ischemic stroke; type 2 diabetes; cancers of the colon and breast; and dementia), disability-adjusted life years (DALYs) and health-related economic impacts. We estimated that 5753 adult users visited the riverside park daily and performed different types of physical activity (walking for leisure or to/from work, cycling, and running). Related to the physical activity conducted on the riverside park, we estimated an annual reduction of 7.3 deaths (95% CI: 5.4; 10.2), and 6.2 cases of diseases (95% CI: 2.0; 11.6). This corresponds to 11.9 DALYs (95% CI: 3.4; 20.5) and an annual health-economic impact of 23.4 million euros (95% CI: 17.2 million; 32.8 million). The urban regeneration intervention of this riverside park provides health and health-related economic benefits to the population using the infrastructure.

February 11 | 2019

Exposure to natural space, sense of community belonging, and adverse mental health outcomes across an urban region.

Rugel EJ, Carpiano RM, Henderson SB, Brauer M.

Environ Res. 2019 Jan 25;171:365-377. DOI: 10.1016/j.envres.2019.01.034


In a rapidly urbanizing world, identifying evidence-based strategies to support healthy design is essential. Although urban living offers increased access to critical resources and can help to mitigate climate change, densely populated neighborhood environments are often higher in many of the physical and psychological stressors that are detrimental to health, and lower in the social capital that is beneficial to health. One component of urban form that can reduce these stressors and improve social capital is nature: greenspace, such as parks and street trees, and bluespace, such as rivers and oceans. In this project, we applied measures from a Natural Space Index previously developed for the Vancouver, Canada census metropolitan area to explore the relationship between distinct measures of natural space and prevalence of (1) major depressive disorder, (2) negative mental health, and (3) psychological distress. In addition, we examined direct associations between natural space exposure and neighborhood social capital, as measured via self-reported sense of community belonging (SoC), as well as the potential mental health benefits of natural space mediated via SoC. Using data from the population-based, cross-sectional 2012 Canadian Community Health Survey-Mental Health (weighted n = 1,930,048), we found no direct associations between any measure of natural space and mental health in models adjusted for 11 demographic, socioeconomic, household arrangement, health, and urban design variables. However, publicly accessible neighborhood nature was associated with increased odds of higher SoC. A 1% increase in the percentage of natural space (combined greenspace and bluespace) within 500 m had an odds ratio [95% confidence interval] of 1.05 [1.00, 1.10] for very strong vs. very weak SoC and 1.04 [1.01, 1.08] for somewhat strong vs. very weak SoC. In addition, higher levels of SoC were associated with improvements in all three mental health outcomes. Mediation tests indicated significant indirect effects of both publicly accessible neighborhood nature variables on reductions in psychological distress and reduced odds of negative mental health via increased sense of SoC. This suggests that natural space has the potential to address the pressing issue of social isolation and, in turn, poor mental health faced by residents of dense urban environments.

February 4 | 2019

Neighbourhood walkability and the incidence of diabetes: an inverse probability of treatment weighting analysis.

Booth GL, Creatore M, Luo J, Fazli GS, Johns A, Rosella LC, Glazier RH, Moineddin R, Gozdyra P, Austin PC.

J Epidemiol Community Health. 2019 Jan 29.. [Epub ahead of print]  DOI:10.1136/jech-2018-210510



People living in highly walkable neighbourhoods tend to be more physically active and less likely to be obese. Whether walkable urban design reduces the future risk of diabetes is less clear.


We used inverse probability of treatment weighting to compare 10-year diabetes incidence between residents living in high-walkability and low-walkability neighbourhoods within five urban regions in Ontario, Canada. Adults (aged 30-85 years) who were diabetes-free on 1 April 2002 were identified from administrative health databases and followed until 31 March 2012 (n=958 567). Within each region, weights reflecting the propensity to live in each neighbourhood type were created based on sociodemographic characteristics, comorbidities and healthcare utilisation and incorporated into region-specific Cox proportional hazards models.


Low-walkability areas were more affluent and had more South Asian residents (6.4%vs3.6%, p<0.001) but fewer residents from other minority groups (16.6%vs21.7%, p<0.001). Baseline characteristics were well balanced between low-walkability and high-walkability neighbourhoods after applying individual weights (standardised differences all <0.1). In each region, high walkability was associated with lower diabetes incidence among adults aged <65 years (overall weighted incidence: 8.2vs9.2 per 1000; HR 0.85, 95% CI 0.78 to 0.93), but not among adults aged ≥65 years (weighted incidence: 20.7vs19.5 per 1000; HR 1.01, 95% CI 0.91 to 1.12). Findings were consistent regardless of income and immigration status.


Younger adults living in high-walkability neighbourhoods had a lower 10-year incidence of diabetes than similarly aged adults living in low-walkability neighbourhoods. Urban designs that support walking may have important benefits for diabetes prevention.

January 28 | 2019

The heat penalty of walkable neighbourhoods. 

O’Brien GA, Ross NA, Strachan IB.

Int J Biometeorol. 2019 Jan 24.. [Epub ahead of print] DOI: 10.1007/s00484-018-01663-0



“Walkability” or walking-friendliness is generally considered a favourable attribute of a neighbourhood that supports physical activity and improves health outcomes. Walkable neighbourhoods tend to have high-density infrastructure and relatively high amounts of concrete and pavement for sidewalks and streets, all of which can elevate local urban temperatures. The objective of this study was to assess whether there is a “heat penalty” associated with more walkable neighbourhoods in Montréal, Québec, Canada, using air temperature measurements taken in real time at street level during a heat event. The mean temperature of “Car-Dependent” neighbourhoods was 26.2 °C (95% CI 25.8, 26.6) whereas the mean temperature of “Walker’s Paradise” neighbourhoods was 27.9 °C (95% CI 27.8, 28.1)-a difference of 1.7 °C (95% CI 1.3, 2.0). There was a strong association between higher walkability of Montréal neighbourhoods and elevated temperature (r = 0.61, p < 0.01); suggestive of a heat penalty for walkable neighbourhoods. Planning solutions that support increased walking-friendliness of neighbourhoods should consider simultaneous strategies to mitigate heat to reduce potential health consequences of the heat penalty.

January 21 | 2019

Residential greenness and mortality in oldest-old women and men in China: a longitudinal cohort study.

John S Ji ScD, Anna Zhu MSc, Chen Bai PhD, Chih-Da Wu PhD, Lijing Yan PhD, Prof Shenglan Tang PhD, Prof Yi Zeng PhD, Peter James ScD.

The Lancet Planetary Health,Volume 3, Issue 1, January 2019, Pages e17-e25




Exposure to natural vegetation, or greenness, might affect health through several pathways, including increased physical activity and social engagement, improved mental health, and reductions in exposure to air pollution, extreme temperatures, and noise. Few studies of the effects of greenness have focused on Asia, and, to the best of our knowledge, no study has assessed the effect on vulnerable oldest-old populations. We assessed the association between residential greenness and mortality in an older cohort in China.


We used five waves (February, 2000–October, 2014) of the China Longitudinal Healthy Longevity Survey (CLHLS), a prospective cohort representative of the general older population in China. We assessed exposure to greenness through satellite-derived Normalised Difference Vegetation Index (NDVI) values in the 250 m and 1250 m radius around the residential address for each individual included in the study. We calculated contemporaneous NDVI values, cumulative NDVI values, and changes in NDVI from the start of the study over time. The health outcome of the study was all-cause mortality, excluding accidental deaths. Mortality rate ratios were estimated with Cox proportional hazards models, adjusted for age, sex, ethnicity, marital status, geographical region, childhood and adult socioeconomic status, social and leisure activity, smoking status, alcohol consumption, and physical activity.


Among 23 754 individuals (mean age at baseline 93 years [SD 7·5]) totaling 80 001 person-years, we observed 18 948 deaths during 14 years of follow-up, between June, 2000, and December, 2014. Individuals in the highest quartile of contemporaneous NDVI values had 27% lower mortality than those in the lowest quartile for the 250 m radius (hazard ratio [HR] 0·73, 95% CI 0·70–0·76), and 30% lower mortality for the 1250 m radius (0·70, 0·67–0·74). No clear association was observed for cumulative NDVI measurements and mortality. We did not detect an association between area-level changes in NDVI and mortality.


Our research suggests that proximity to more green space is associated with increased longevity, which has policy implications for the national blueprint of ecological civilisation and preparation for an ageing society in China.

January 14 | 2019

Residential noise exposure and the longitudinal risk of hospitalization for depression after pregnancy: Postpartum and beyond. 

He S, Smargiassi A, Low N, Bilodeau-Bertrand M, Ayoub A, Auger N.

Environ Res. 2018 Dec 3;170:26-32. doi: 10.1016/j.envres.2018.12.001  [Epub ahead of print]



Depression is a major public health concern, but the link with the built environment is unclear. We sought to determine the relationship between residential noise during pregnancy and later risk of severe depression in women.


We analyzed a population-based cohort of 140,456 women with no documented history of mental illness who were pregnant in Montreal between 2000 and 2016. We obtained residential noise estimates (LAeq. 24 h, Lden, Lnight) from land use regression models, and followed the women over time for up to 18 years after pregnancy to identify subsequent hospitalizations for depression or other mental disorders. We used Cox regression to compute hazard ratios and 95% confidence intervals (CI) adjusted for maternal characteristics.


There were 8.0 incident hospitalizations for depression and 16.4 for other mental disorders per 10,000 person-years in women exposed to an LAeq. 24 h of 60-64.9 dB(A). The incidence was lower for noise at < 55 dB(A), with 7.4 hospitalizations for depression and 13.8 for other mental disorders per 10,000 person-years. Compared with 50 dB(A), an LAeq. 24 h of 60 dB(A) was associated with 1.16 times (95% CI 0.84-1.62) the risk of depression hospitalization, and 1.34 times (95% CI 1.04-1.74) the risk of other mental disorders. Associations were more prominent for Lnight, with 1.32 times (95% CI 1.08-1.63) the risk of depression hospitalization at 60 dB(A) and 1.68 times the risk (95% CI 1.05-2.67) at 70 dB(A).


Pregnant women exposed to noise, especially nighttime noise, have a greater risk of hospitalization for depression and other mental disorders later in life. Residential noise may be a risk factor for depression after pregnancy.