Residential proximity to green spaces and breast cancer risk: The multicase-control study in Spain (MCC-Spain)

Background: Breast cancer is the main cause of cancer mortality among women. Green spaces have been recently associated with reduced cancer mortality among women. Mechanisms explaining the beneficial effect of green spaces include increased levels of physical activity and reduced exposure to air pollution, which have been both associated with cancer development. Objectives: To investigate the associations between presence of urban green areas, presence of agricultural areas and surrounding greenness and risk of breast cancer, and to assess whether these associations are mediated by physical activity and/or air pollution levels. Methods: We geocoded the current residence of 1129 breast cancer cases and 1619 controls recruited between 2008 and 2013 in ten provinces of Spain, as part of the MCC-Spain study. We assigned different indicators of exposure to green spaces in a buffer of 300 m, and in nested buffers of 100 m and 500 m around the residence: presence of urban green areas according to Urban Atlas, presence of agricultural areas according to CORINE Land Cover 2006, and surrounding greenness according to the average of the Normalized Difference Vegetation Index. We used logistic mixed-effects regression models with a random effect for hospital adjusting for potential confounders. We explored the effect of several potential effect modifiers. We assessed mediation effect by physical activity and levels of air pollution. Results: Presence of urban green areas was associated with reduced risk of breast cancer after adjusting for age, socio-economic status at individual and at area level, education, and number of children [OR (95%CI) = 0.65 (0.49–0.86)]. There was evidence of a linear trend between distance to urban green areas and risk of breast cancer. On the contrary, presence of agricultural areas and surrounding greenness were associated with increased risk of breast cancer [adjusted OR (95%CI) = 1.33 (1.07–1.65) and adjusted OR (95%CI) = 1.27 (0.92–1.77), respectively]. None of the associations observed were mediated by levels of physical activity or levels or air pollution. Conclusions: The association between green spaces and risk of breast cancer is dependent on land-use. The confirmation of these results in other settings and the study of potential mechanisms for the associations observed are needed to advance the understanding on the potential effects of green spaces on health

Green spaces, excess weight and obesity in Spain

Background: The epidemiological evidence on green spaces and obesity is inconsistent. Objectives: To study the association of access to green spaces and surrounding greenness with obesity in Spain. Methods: We enrolled 2354 individuals 20-85 years from urban areas of seven provinces of Spain between 2008-13. Subjects were randomly selected population controls of the MCC-Spain case-control study. We geocoded current residences and defined exposures in a buffer of 300 m around them: i) access to green space, identified using Urban Atlas, and ii) levels of surrounding greenness, measured by the Normalized Difference Vegetation Index. We examined excess weight/obesity as binary outcomes based on body mass index and waist-hip ratio. We examined effect modification by genetic factors, sex and individual socio-economic status and mediation by physical activity and concentrations of PM2.5 and NO2. To assess potential effect modification by genetic factors, we used a polygenic risk score based on obesity polymorphisms detected in genome-wide association studies. We used logistic mixed-effects models with a random effect for catchment area adjusted for potential confounders. Results: Access to green space was associated with a reduced risk of excess weight/obesity after adjusting for confounders [excess weight: OR (95%CI) = 0.82 (0.63, 1.07), p-value = 0.143; abdominal obesity: OR (95%CI) = 0.68 (0.45, 1.01), p-value = 0.057]. In the stratified analysis, this association was only observed in women. Associations between surrounding greenness and excess weight/obesity were null or modest based on a 1 IQR increase in NDVI [excess weight: OR (95%CI) = 0.99 (0.88, 1.11), p-value = 0.875; abdominal obesity: OR (95%CI) = 0.91 (0.79, 1.05), p-value = 0.186]. The observed associations were not mediated by physical activity or air pollution. Discussion: Access to green space may be associated with decreased risk of excess weight/obesity among women in Spain. Mechanisms explaining this association remain unclear.The study was conducted with the Support of Department of Health, Catalan Government grant SLT002/16/00223. The study was partially funded by the “Acción Transversal del Cáncer", approved on the Spanish Ministry Council on the 11th October 2007, by the Instituto de Salud Carlos III-FEDER (PI08/1770, PI08/0533, PI08/1359, PS09/00773-Cantabria, PS09/01903-Valencia, PI11/01403, PI11/01889-FEDER, PI11/01810, PI12/00488, PI12/00265, PI12/01270, PI12/00715, PI14/01219, PI14/0613, PI15/00069), by the Fundación Marqués de Valdecilla (API 10/09), by the ICGC International Cancer Genome Consortium CLL (The ICGC CLL-Genome Project is funded by Spanish Ministerio de Economía y Competitividad (MINECO) through the Instituto de Salud Carlos III (ISCIII) and Red Temática de Investigación del Cáncer (RTICC) del ISCIII (RD12/0036/0036), by the Junta de Castilla y León (LE22A10-2), by the Consejería de Salud of the Junta de Andalucía (PI-0571-2009, PI-0306-2011, salud201200057018tra), by the Conselleria de Sanitat of the Generalitat Valenciana (AP_061/10), by the Recercaixa (2010ACUP 00310), by the Regional Government of the Basque Country, by the Consejería de Sanidad de la Región de Murcia, by the European Commission grants FOOD-CT-2006-036224-HIWATE, by the Catalan Government- Agency for Management of University and Research Grants (AGAUR) grants 2017SGR723 and 2014SGR850, by the Fundación Caja de Ahorros de Asturias and by the University of Oviedo. ISGlobal is a member of the CERCA Programme, Generalitat de Catalunya. Biological samples were stored at the biobanks supported by Instituto de Salud Carlos III- FEDER: Parc de Salut MAR Biobank (MARBiobanc) (RD09/0076/00036), “Biobanco La Fe” (RD 09 0076/00021) and FISABIO Biobank (RD09 0076/00058