title: Association between body mass index and cortical thickness: among elderly cognitively normal men and women.
abstract: BACKGROUND
  There is increasing evidence of a relationship between underweight or obesity and dementia risk. Several studies have investigated the relationship between body weight and brain atrophy, a pathological change preceding dementia, but their results are inconsistent. Therefore, we aimed to evaluate the relationship between body mass index (BMI) and cortical atrophy among cognitively normal participants.
  
  
  METHODS
  We recruited cognitively normal participants (n = 1,111) who underwent medical checkups and detailed neurologic screening, including magnetic resonance imaging (MRI) in the health screening visits between September 2008 and December 2011. The main outcome was cortical thickness measured using MRI. The number of subjects with five BMI groups in men/women was 9/9, 148/258, 185/128, 149/111, and 64/50 in underweight, normal, overweight, mild obesity, and moderate to severe obesity, respectively. Linear and non-linear relationships between BMI and cortical thickness were examined using multiple linear regression analysis and generalized additive models after adjustment for potential confounders.
  
  
  RESULTS
  Among men, underweight participants showed significant cortical thinning in the frontal and temporal regions compared to normal weight participants, while overweight and mildly obese participants had greater cortical thicknesses in the frontal region and the frontal, temporal, and occipital regions, respectively. However, cortical thickness in each brain region was not significantly different in normal weight and moderate to severe obesity groups. Among women, the association between BMI and cortical thickness was not statistically significant.
  
  
  CONCLUSIONS
  Our findings suggested that underweight might be an important risk factor for pathological changes in the brain, while overweight or mild obesity may be inversely associated with cortical atrophy in cognitively normal elderly males.
authors.affiliation: Samsung Advanced Institute for Health Sciences and Technology,Sungkyunkwan University,Seoul,South Korea.
authors.forename: Hojeong
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Preventive Medicine,Yonsei University College of Medicine,Seoul,South Korea.
authors.forename: Changsoo
authors.initials: C
authors.lastname: Kim
authors.affiliation: Department of Neurology,Samsung Medical Center,School of Medicine,Sungkyunkwan University,Seoul,South Korea.
authors.forename: Sang Won
authors.initials: SW
authors.lastname: Seo
authors.affiliation: Department of Neurology,Samsung Medical Center,School of Medicine,Sungkyunkwan University,Seoul,South Korea.
authors.forename: Duk L
authors.initials: DL
authors.lastname: Na
authors.affiliation: Department of Neurology,Samsung Medical Center,School of Medicine,Sungkyunkwan University,Seoul,South Korea.
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Center for Health Promotion,Samsung Medical Center,Seoul,South Korea.
authors.forename: Mira
authors.initials: M
authors.lastname: Kang
authors.affiliation: Center for Health Promotion,Samsung Medical Center,Seoul,South Korea.
authors.forename: Hee-Young
authors.initials: HY
authors.lastname: Shin
authors.affiliation: Center for Health Promotion,Samsung Medical Center,Seoul,South Korea.
authors.forename: Seong Kyung
authors.initials: SK
authors.lastname: Cho
authors.affiliation: Samsung Advanced Institute for Health Sciences and Technology,Sungkyunkwan University,Seoul,South Korea.
authors.forename: Sang Eon
authors.initials: SE
authors.lastname: Park
authors.affiliation: Samsung Advanced Institute for Health Sciences and Technology,Sungkyunkwan University,Seoul,South Korea.
authors.forename: Jeongmin
authors.initials: J
authors.lastname: Lee
authors.affiliation: Samsung Advanced Institute for Health Sciences and Technology,Sungkyunkwan University,Seoul,South Korea.
authors.forename: Jung Won
authors.initials: JW
authors.lastname: Hwang
authors.affiliation: Department of Biomedical Engineering,Hanyang University,Seoul,South Korea.
authors.forename: Seun
authors.initials: S
authors.lastname: Jeon
authors.affiliation: Department of Biomedical Engineering,Hanyang University,Seoul,South Korea.
authors.forename: Jong-Min
authors.initials: JM
authors.lastname: Lee
authors.affiliation: Department of Neurology,Samsung Medical Center,School of Medicine,Sungkyunkwan University,Seoul,South Korea.
authors.forename: Geon Ha
authors.initials: GH
authors.lastname: Kim
authors.affiliation: Department of Neurology,Samsung Medical Center,School of Medicine,Sungkyunkwan University,Seoul,South Korea.
authors.forename: Hanna
authors.initials: H
authors.lastname: Cho
authors.affiliation: Department of Neurology,Samsung Medical Center,School of Medicine,Sungkyunkwan University,Seoul,South Korea.
authors.forename: Byoung Seok
authors.initials: BS
authors.lastname: Ye
authors.affiliation: Department of Neurology,Gachon University Gil Medical Center,Incheon,South Korea.
authors.forename: Young
authors.initials: Y
authors.lastname: Noh
authors.affiliation: Department of Neurology,College of Medicine,Inha University,Incheon,South Korea.
authors.forename: Cindy W
authors.initials: CW
authors.lastname: Yoon
authors.affiliation: Departments of Epidemiology and Medicine and Welch Center for Prevention,Epidemiology,and Clinical Research,Johns Hopkins University Bloomberg School of Public Health,Baltimore,Maryland,USA.
authors.forename: Eliseo
authors.initials: E
authors.lastname: Guallar
mesh_terms: D000368:Aged; D001284:Atrophy; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping / Q000379:methods; D003704:Dementia / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D005260:Female; D006801:Humans; D007361:Intelligence Tests; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D012044:Regression Analysis; D056910:Republic of Korea; D012307:Risk Factors; D012737:Sex Factors