title: The impact of body mass index and central obesity on the spino-pelvic parameters: a correlation study.
abstract: BACKGROUND
  Obesity is an increasing problem of epidemic proportion, and it is associated with various musculoskeletal disorders, including impairment of the spine. However, the relationship between obesity and spino-pelvic parameters remains to date unsupported by an objective measurement of the mechanical behavior of the spino-pelvic parameters depending on body mass index (BMI) and the presence of central obesity. Such analysis may provide a deeper understanding of this relationship.
  
  
  OBJECTIVE
  To assess whether BMI and central obesity are associated with modifications on spino-pelvic parameters and determine if exists any correlation between BMI and obesity with the type of lumbar lordosis (LL).
  
  
  METHODS
  A cross-sectional study with 200 participants was conducted. Parameters measured were LL, pelvic tilt, sacral slope, and pelvic incidence (PI), using lumbosacral radiographs in lateral view. Subjects were classified depending on BMI. In a secondary analysis, the subjects were categorized into two groups depending on the presence or not of elevated abdominal circumference. The categorical variables were compared using Chi-square test, and the mean values were compared using ANOVA and student t test. A Spearman correlation test was used to analyze the correlation between BMI categories and LL types.
  
  
  RESULTS
  From the total of participants, there were 51 (25.5 %) normal weight subjects, 93 (46.5 %) overweight, and 56 (28 %) obese individuals. The spino-pelvic parameters among these groups are practically equal. The correlation between the different BMI categories and LL types is poor 0.06 (P = 0.34). In a secondary analysis, grouping the participants in obese and non-obese, the results showed that obesity is modestly positively associated with increasing of spino-pelvic parameters values, in particular with PI (P = 0.078). The comparison made between the presence or not of central obesity, interestingly did not show significant differences.
  
  
  CONCLUSIONS
  Despite the results did not reach statistically significant differences, the results indicate that the obese spine is slightly different from the non-obese spine. Therefore, this relationship deserves future attention.
authors.affiliation: Spine Surgery Service, Instituto Nacional de Rehabilitación, Calzada México Xochimilco #289 Col. Arenal de Guadalupe, Zip Code 14389, Mexico City, Mexico.
authors.forename: S
authors.initials: S
authors.lastname: Romero-Vargas
authors.forename: B
authors.initials: B
authors.lastname: Zárate-Kalfópulos
authors.forename: E
authors.initials: E
authors.lastname: Otero-Cámara
authors.forename: L
authors.initials: L
authors.lastname: Rosales-Olivarez
authors.forename: A
authors.initials: A
authors.lastname: Alpízar-Aguirre
authors.forename: Eugenio
authors.initials: E
authors.lastname: Morales-Hernández
authors.forename: Alejandro
authors.initials: A
authors.lastname: Reyes-Sánchez
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001696:Biomechanical Phenomena / Q000502:physiology; D015992:Body Mass Index; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008141:Lordosis / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008297:Male; D056128:Obesity, Abdominal / Q000150:complications* / Q000503:physiopathology; D050177:Overweight / Q000150:complications; D010384:Pelvic Bones / Q000000981:diagnostic imaging*; D011859:Radiography; D012307:Risk Factors; D013131:Spine / Q000000981:diagnostic imaging*