title: Migraine and body mass index categories: a systematic review and meta-analysis of observational studies.
abstract: BACKGROUND
  Several studies have assessed the associations between migraine and underweight, pre-obesity or obesity, with conflicting results. To assess the consistency of the data on the topic, we performed a systematic review and meta-analysis of the available observational studies.
  
  
  METHODS
  Multiple electronic databases were systematically searched up to October 2014 for studies assessing the association between migraine and body mass index categories (underweight, pre-obesity, or obesity).
  
  
  RESULTS
  Out of 2,022 records, we included 15 studies. When considering the 11 studies following the World Health Organization BMI cutoffs, we found an increased risk of having migraine in underweight subjects (pooled adjusted effect estimate [PAEE] 1.21; 95% CI, 1.07-1.37; P = 0.002) and in obese women (PAEE 1.44; 95% CI, 1.05-1.97; P = 0.023) as compared with normal weight subjects; additionally, pre-obese subjects had an increased risk of having chronic migraine (PAEE 1.39; 95% CI, 1.13-1.71; P = 0.002). When considering all the 15 studies, we additionally found an increased risk of having migraine in obese as compared with normal weight subjects (PAEE 1.14; 95% CI, 1.02-1.27; P = 0.017); additionally, obese subjects had an increased risk of having chronic migraine (PAEE 1.75; 95% CI, 1.33-2.29; P < 0.001). The pooled analysis did not indicate an increased risk of having migraine in pre-obese subjects.
  
  
  CONCLUSIONS
  The meta-analysis of the available observational studies suggested an association between migraine and obesity likely mediated by gender and migraine frequency. Further studies taking into account gender, migraine type, frequency, activity, and duration could provide more robust evidence.
authors.affiliation: Department of Applied Clinical Sciences and Biotechnology, Institute of Neurology, University of L'Aquila, 67100, L'Aquila, Italy. raffaele.ornello@gmail.com.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Ornello
authors.affiliation: Department of Applied Clinical Sciences and Biotechnology, Institute of Neurology, University of L'Aquila, 67100, L'Aquila, Italy. ripapatrizia@gmail.com.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Ripa
authors.affiliation: Department of Applied Clinical Sciences and Biotechnology, Institute of Neurology, University of L'Aquila, 67100, L'Aquila, Italy. pistoiafrancesca@hotmail.com.
authors.forename: Francesca
authors.initials: F
authors.lastname: Pistoia
authors.affiliation: Department of Applied Clinical Sciences and Biotechnology, Institute of Neurology, University of L'Aquila, 67100, L'Aquila, Italy. degandiana@gmail.com.
authors.forename: Diana
authors.initials: D
authors.lastname: Degan
authors.affiliation: Department of Applied Clinical Sciences and Biotechnology, Institute of Neurology, University of L'Aquila, 67100, L'Aquila, Italy. cindy.tiseo@gmail.com.
authors.forename: Cindy
authors.initials: C
authors.lastname: Tiseo
authors.affiliation: Department of Applied Clinical Sciences and Biotechnology, Institute of Neurology, University of L'Aquila, 67100, L'Aquila, Italy. a_carolei@yahoo.com.
authors.forename: Antonio
authors.initials: A
authors.lastname: Carolei
authors.affiliation: Department of Applied Clinical Sciences and Biotechnology, Institute of Neurology, University of L'Aquila, 67100, L'Aquila, Italy. simona.sacco@yahoo.com.
authors.forename: Simona
authors.initials: S
authors.lastname: Sacco
mesh_terms: D015992:Body Mass Index; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008881:Migraine Disorders / Q000453:epidemiology*; D009765:Obesity / Q000453:epidemiology*; D012306:Risk; D013851:Thinness / Q000453:epidemiology*