title: Relationship between body mass index and depression in women: A 7-year prospective cohort study. The APNA study.
abstract: BACKGROUND
  The association between body mass index (BMI) and depression is complex and controversial. The present study examined the relationship between BMI and new-onset depression during 7 years of follow-up in 20,212 adult women attending Primary Health Care Centres in Navarra, Spain.
  
  
  METHODS
  The Atención Primaria de Navarra (APNA) study is a dynamic prospective cohort study. A total of 20,212 women aged 18-99 years (mean age: 50.7 ± 18.5 years) without depression at baseline were selected from 2004 to 2011. We estimated the incidence of depression. We used the Kaplan-Meier analysis to predict the survival curve. The risk of depression onset according to different measures of BMI at baseline was assessed using Cox regression analyses.
  
  
  RESULTS
  During the 7 years of follow-up, depression appeared in 8.9% (95% CI 8.5-9.3). The highest rates of depression incidence at follow-up occurred in underweight and obese women (9.8% [95% CI 7.3-12.9] and 10.3% [95% CI 9.5-11.1] respectively). The distribution of depression incidence by weight category was U-shaped. The risk of depression increased over time with an observed Kaplan-Meier estimation of 6.67. After adjusting for age, underweight and obese women at baseline have increased risk of depression onset during the follow-up period compared with normal weight women (HR=1.48, 95% CI=1.09-2.00 and HR=1.14, 95% CI=1.01-1.29 respectively).
  
  
  CONCLUSIONS
  In this 7-year prospective study in the APNA women population, depression emerged in 8.9%. Being underweight or obese (not overweight) at baseline is significantly associated with future onset of depression.
authors.affiliation: Department of Health Science, Public University of Navarra, Avenida Barañain s/n, 31008 Pamplona, Spain; Servicio Navarro de Salud, Spain. Electronic address: elenamartinr@gmail.com.
authors.forename: E
authors.initials: E
authors.lastname: Martin-Rodriguez
authors.affiliation: Department of Health Science, Public University of Navarra, Avenida Barañain s/n, 31008 Pamplona, Spain; Department of Preventive Medicine. Clínica Universidad de Navarra, Pamplona, Spain; IdiSNA (Navarra Institute for Health Research), Spain.
authors.forename: F
authors.initials: F
authors.lastname: Guillen-Grima
authors.affiliation: Department of Psychiatry, Clínica Universidad de Navarra, Pamplona, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Aubá
authors.affiliation: IdiSNA (Navarra Institute for Health Research), Spain; Department of Nutrition, Food Science and Physiology. University of Navarra, Pamplona, Spain; Biomedical Research Centre in Physiopathology of Obesity and Nutrition (CIBERobn), Physiopathology of Obesity and Nutrition, Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Martí
authors.affiliation: Department of Health Science, Public University of Navarra, Avenida Barañain s/n, 31008 Pamplona, Spain; Servicio Navarro de Salud, Spain; IdiSNA (Navarra Institute for Health Research), Spain.
authors.forename: A
authors.initials: A
authors.lastname: Brugos-Larumbe
mesh_terms: D000328:Adult; D015992:Body Mass Index; D015331:Cohort Studies; D003863:Depression / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D005260:Female; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D009765:Obesity / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D011446:Prospective Studies; D012044:Regression Analysis; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology
keywords: Body mass index; Depression; Obesity; Primary health care; Underweight