Increased urban greenness associated with improved mental health among middle-aged and older adults of the Canadian Longitudinal Study on Aging (CLSA).

Some studies suggest that residential surrounding greenness is associated with improved mental health. Few of these studies have focussed on middle-aged and older adults, explored the modifying effects of social determinants of health, or accounted for the extent to which individuals interact with their neighbourhood environments. We analysed cross-sectional data collected from 26,811 urban participants of the Canadian Longitudinal Study of Aging who were between 45 and 86 years of age. Participants provided details on socioeconomic characteristics, health behaviours, and their frequency of neighbourhood interactions. The Normalized Difference Vegetation Index (NDVI), a measure of greenness, was assigned to participants' residential addresses at a buffer distance of 500 m. Four self-reported measures of mental health were considered: The Center for Epidemiologic Studies Depression Scale (CES-D-10; short scale), past diagnosis of clinical depression, perceptions of mental health, and the Satisfaction with Life Scale (SWLS). Regression models were used to describe associations between greenness and these outcomes, and spline models were fit to characterize the exposure-response function between greenness and CES-D-10 scores. Stratified analyses evaluated whether associations varied by sociodemographic status. In adjusted models, we observed a 5% (Odds Ratio (OR) = 0.95; 95% CI = 0.90, 0.99) reduced odds of depressive symptoms in relation to an interquartile range increase of NDVI (0.06) within a 500 m buffer of the participant's residence. Similarly, we found an inverse association with a self-reported clinical diagnosis of depression (OR = 0.97; 95% CI = 0.92-1.01). Increases in surrounding greenness were associated with improved perceptions of mental health, and the SWLS. Our spline analyses found that beneficial effects between greenness and the CES-D-10 were strongest among those of lower income. These findings suggest that residential greenness has mental health benefits, and that interventions to increase urban greenness can help reduce social inequalities in mental health.

Abraham Cottagiri S ，Villeneuve PJ ，Raina P ，Griffith LE ，Rainham D ，Dales R ，Peters CE ，Ross NA ，Crouse DL ... -  《-》

Does urban greenness reduce loneliness and social isolation among Canadians? A cross-sectional study of middle-aged and older adults of the Canadian Longitudinal Study on Aging (CLSA).

Villeneuve PJ ，Gill GK ，Cottagiri SA ，Dales R ，Rainham D ，Ross NA ，Dogan H ，Griffith LE ，Raina P ，Crouse DL ... -  《-》

Residential greenness and indicators of stress and mental well-being in a Canadian national-level survey.

Residential proximity to greenness in urban areas has been shown to confer a number of health benefits, including improved mental health. We investigated whether greenness was associated with self-reported stress, distress, and mental health among adult participants of multiple cycles of a national Canadian health survey, and whether these associations varied by sex, age, income, and neighbourhood characteristics. Our study population included 397,900 participants of the Canadian Community Health Survey, 18 years of age or older, who lived in census metropolitan areas between 2000 and 2015. We used the Normalized Difference Vegetation Index (NDVI) to characterize participants' exposure to greenness within 250 m, 500 m, and 1 km buffers from a representative location of their postal code. Health outcomes included: self-reported perceptions of life stress, psychological distress, and self-rated mental health. We used multiple regression models, adjusted for relevant individual and neighbourhood-level variables to estimate associations (and 95% confidence intervals) between each outcome and exposure to greenness. In models with all participants, we observed 6% lower odds of poor self-rated mental health per increase in the interquartile range (i.e., 0.12) of NDVI within a 500 m buffer. Across the three outcomes, we found substantial heterogeneity in effect size across categories of sex, age, and community-level indicators of deprivation and urban form. For example, each incremental increase in greenness exposure was associated with a reduction of 0.61 (95% CI: 0.81 to -0.51) on the K10 psychological distress score among those living in the active core of cities, and with an increase of 0.07 (95% CI: 0.03-0.12) on this score among those living in the most suburban areas. Our results indicate that the potential benefits of residential greenness on mental health vary across personal and neighbourhood-level characteristics and are sensitive to how the outcome is measured. Additional research is needed to understand which features of greenness are most relevant to different sub-groups of the population to maximize these health benefits.

Crouse DL ，Pinault L ，Christidis T ，Lavigne E ，Thomson EM ，Villeneuve PJ ... -  《-》

Urban greenness and physical activity in a national survey of Canadians.

Recent research suggests that urban greenness has important beneficial effects on health. While some epidemiological studies have investigated associations between measures of greenness and participation in physical activities, the findings have been inconsistent and several have relied on self-reported rather than objectively determined measures of greenness. Further, there have been few national studies. Our aim was to characterize associations between residential measures of greenness and physical activity within a nationally representative sample of Canadians. Moreover, we sought to determine to what extent these associations were modified by age, sex and income. Our analyses are based on data collected from participants of the 2001 Canadian Community Health Survey. Analyses were restricted to 69,910 individuals who were: 20 years of age and older, lived in urban areas, and for whom a residential measure of greenness could be assigned. The Normalised Difference Vegetation Index (NDVI), which is an objectively defined measure of greenness based on satellite imaging, was assigned to the residential addresses of the participants. Our NDVI values were based on 30 m and 500 m buffers from the centroid of the provided postal codes. Logistic regression was used to estimate odds ratios (ORs) and their 95% confidence intervals to describe associations between greenness and several measures of physical activity. The ORs were adjusted for age, sex, smoking status, marital status, and income. We found that participants who resided in the highest quartile of greenness, based on a 500 m buffer, were more likely to participate in leisure-time physical activity (adjusted OR=1.34, 95% CI=1.25-1.44) when compared to those in the lowest quartile. Positive associations were observed between greenness and physical activity in all income groupings. A key finding was the observation of a stronger association between greenness and measures of physical activity among younger adults, especially women. Our findings have important public health implications as they suggest that access to urban green environments contributes to increased participation in leisure-time physical activity which has demonstrable health benefits.

McMorris O ，Villeneuve PJ ，Su J ，Jerrett M ... -  《-》

Residential proximity to greenness and adverse birth outcomes in urban areas: Findings from a national Canadian population-based study.

Over the last decade, several studies have reported that residential proximity to vegetation, or 'greenness', is associated with improved birth outcomes, including for term birth weight (TBW), preterm birth (PTB), and small for gestational age (SGA). However, there remain several uncertainties about these possible benefits including the role of air pollution, and the extent to they are influenced socioeconomic status. We addressed these gaps using a national population-based study of 2.2 million singleton live births in Canadian metropolitan areas between 1999 and 2008. Exposures to greenness, fine particulate matter (PM2.5), and nitrogen dioxide (NO2) were assigned to infants using the postal code of their mother's residence at the time of birth. The Normalized Difference Vegetation Index (NDVI) was used to characterize greenness, while estimates of ambient PM2.5 and NO2 were estimated using remote sensing, and a national land-use regression surface, respectively. Multivariable regression analysis was performed to describe associations between residential greenness and the birth outcomes. Stratified analyses explored whether these associations were modified by neighbourhood measures of socioeconomic status. Mothers who lived in greener areas had a lower risk of low TBW, PTB, and SGA babies. These associations persisted after adjustment for ambient NO2 and PM2.5. Specifically, in fully adjusted models, an interquartile range (IQR = 0.16) increase in the NDVI within a residential buffer of 250 m yielded odds ratios of 0.93 (95% confidence interval (CI): 0.92, 0.94), 0.94 (95% CI: 0.92, 0.95), and 0.94 (95% CI: 0.93, 0.95) for the outcomes of PTB, low TBW, and SGA, respectively. Similarly, an IQR increase in greenness was associated with a 16.3 g (95% CI: 15.3, 17.4) increase in TBW. We found inverse associations between greenness and the occurrence of adverse birth outcomes regardless of the socioeconomic status of the neighbourhood. Our findings support the hypothesis that residential greenness contributes to healthier pregnancies, that these associations are independent from exposure to air pollution. , and that proximity to greenness benefits all mothers regardless of socioeconomic status.

Villeneuve PJ ，Lam S ，Tjepkema M ，Pinault L ，Crouse DL ，Osornio-Vargas AR ，Hystad P ，Jerrett M ，Lavigne E ，Stieb DM ... -  《-》