title: Longitudinal BMI trajectories in multiple sclerosis: Sex differences in association with disease severity.
abstract: BACKGROUND
  Adolescent obesity is a risk factor for multiple sclerosis (MS), but little is known about changes in body mass index (BMI) after MS onset.
  
  
  OBJECTIVE
  To assess the relationship between MS and longitudinal changes in BMI.
  
  
  METHODS
  We analyzed prospectively collected BMIs in a cohort of patients with adult-onset MS and matched adult healthy controls (HC) gathered from the same hospital network central clinical data registry.
  
  
  RESULTS
  We made three main observations. First, at baseline MS patients had a significantly higher BMI than HC (age- and sex- adjusted mean difference=0.57; 95% CI: 0.15, 0.99; p=0.008). Second, a significant age by MS status interaction was observed (p<0.0001), such that in MS, BMIs did not increase significantly higher in older individuals, whereas BMIs in HCs were higher with increasing age. Third, we observed sex-specific associations with disease severity: higher BMI was associated with higher cross-sectional EDSS in women, but with lower EDSS in men (p=0.003, N=758). There were no longitudinal associations between BMI and EDSS in either sex or in the entire cohort (p=0.65, N=772).
  
  
  CONCLUSIONS
  After MS onset, patients may not experience age-expected increases in BMI. BMI may have sex-specific associations with MS disability scores. More refined measures of body composition are warranted in future studies to distinguish adiposity from muscle mass.
authors.affiliation: Partners Multiple Sclerosis Center, Department of Neurology, Brigham and Women's Hospital, Brookline, MA 02445, USA; Harvard Medical School, Boston, MA 02115, USA. Electronic address: riley_bove@post.harvard.edu.
authors.forename: R
authors.initials: R
authors.lastname: Bove
authors.affiliation: Partners Multiple Sclerosis Center, Department of Neurology, Brigham and Women's Hospital, Brookline, MA 02445, USA. Electronic address: ajmusallam@gmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Musallam
authors.affiliation: Partners Multiple Sclerosis Center, Department of Neurology, Brigham and Women's Hospital, Brookline, MA 02445, USA; Harvard Medical School, Boston, MA 02115, USA. Electronic address: zxia1@post.harvard.edu.
authors.forename: Z
authors.initials: Z
authors.lastname: Xia
authors.affiliation: Partners Multiple Sclerosis Center, Department of Neurology, Brigham and Women's Hospital, Brookline, MA 02445, USA; Partners Pediatric Multiple Sclerosis Center, Massachusetts General Hospital, Boston, MA 02114, USA. Electronic address: baruch.natalie352@gmail.com.
authors.forename: N
authors.initials: N
authors.lastname: Baruch
authors.affiliation: Partners Multiple Sclerosis Center, Department of Neurology, Brigham and Women's Hospital, Brookline, MA 02445, USA; Department G.F. Ingrassia, Section of Neurosciences, University of Catania, Italy. Electronic address: silvia.messina@unict.it.
authors.forename: S
authors.initials: S
authors.lastname: Messina
authors.affiliation: Partners Multiple Sclerosis Center, Department of Neurology, Brigham and Women's Hospital, Brookline, MA 02445, USA; Harvard Medical School, Boston, MA 02115, USA; Massachusetts General Hospital Biostatistics Center, Boston, MA 02114, USA. Electronic address: bchealy@partners.org.
authors.forename: B C
authors.initials: BC
authors.lastname: Healy
authors.affiliation: Partners Multiple Sclerosis Center, Department of Neurology, Brigham and Women's Hospital, Brookline, MA 02445, USA; Harvard Medical School, Boston, MA 02115, USA; Partners Pediatric Multiple Sclerosis Center, Massachusetts General Hospital, Boston, MA 02114, USA. Electronic address: tchitnis@partners.org.
authors.forename: T
authors.initials: T
authors.lastname: Chitnis
mesh_terms: D000328:Adult; D000367:Age Factors; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009103:Multiple Sclerosis / Q000453:epidemiology* / Q000503:physiopathology*; D050177:Overweight / Q000453:epidemiology / Q000503:physiopathology; D011446:Prospective Studies; D012189:Retrospective Studies; D012720:Severity of Illness Index; D012737:Sex Factors
keywords: Body mass index; Multiple sclerosis; Obesity; Sex differences