title: [Biodiversity and depressive symptoms in Mexican adults: Exploration of beneficial environmental effects].
abstract: BACKGROUND
  Depression is a highly prevalent illness among adults, and it is the second most frequently reported mental disorder in urban settings in México. Exposure to natural environments and its components may improve the mental health of the population.
  
  
  OBJECTIVE
  To evaluate the association between biodiversity indicators and the prevalence of depressive symptoms among the adult population (20 to 65 years of age) in México.
  
  
  METHODS
  Information from the Encuesta Nacional de Salud y Nutrición 2006 (ENSANUT 2006) and the Compendio de Estadísticas Ambientales 2008 was analyzed. A biodiversity index was constructed based on the species richness and ecoregions in each state. A multilevel logistic regression model was built with random intercepts and a multiple logistic regression was generated with clustering by state.
  
  
  RESULTS
  The factors associated with depressive symptoms were being female, self-perceived as indigenous, lower education level, not living with a partner, lack of steady paid work, having a chronic illness and drinking alcohol. The biodiversity index was found to be inversely associated with the prevalence of depressive symptoms when defined as a continuous variable, and the results from the regression were grouped by state (OR=0.71; 95% CI = 0.59-0.87).
  
  
  CONCLUSIONS
  Although the design was cross-sectional, this study adds to the evidence of the potential benefits to mental health from contact with nature and its components.
authors.affiliation: Ingeniería Ambiental Industrial, Universidad Estatal de Sonora, Hermosillo, México, Departamento de Medicina y Ciencias de la Salud, Universidad de Sonora, Hermosillo, México.
authors.forename: Héctor
authors.initials: H
authors.lastname: Duarte-Tagles
authors.affiliation: Centro de Investigación en Evaluación y Encuestas, Instituto Nacional de Salud Pública, Cuernavaca, México.
authors.forename: Aarón
authors.initials: A
authors.lastname: Salinas-Rodríguez
authors.affiliation: Departamento de Salud Pública, Escuela de Medicina, Facultad de Salud, Universidad Industrial de Santander, Bucaramanga, Colombia.
authors.forename: Álvaro J
authors.initials: ÁJ
authors.lastname: Idrovo
authors.affiliation: Instituto de Ecología (Unidad Hermosillo), Universidad Nacional Autónoma de México, Hermosillo, México.
authors.forename: Alberto
authors.initials: A
authors.lastname: Búrquez
authors.affiliation: Departamento de Psicología, Universidad de Sonora, Hermosillo, México.
authors.forename: Víctor
authors.initials: V
authors.lastname: Corral-Verdugo
mesh_terms: D000328:Adult; D000368:Aged; D044822:Biodiversity; D003430:Cross-Sectional Studies; D003863:Depression / Q000453:epidemiology* / Q000517:prevention & control*; D004782:Environmental Health; D005260:Female; D006801:Humans; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D055815:Young Adult