title: Ageing and obesity indices influences the tactile acuity of the low back regions: A cross-sectional study.
abstract: OBJECTIVE
  Two-point discrimination threshold (TPDT) is increased in individuals with chronic low back pain. TPDT reference values and their determinants are required for clinical applications. Therefore, the aims of this research are to establish reference values for TPDT of the low back regions in healthy individuals, stratified for age, and to investigate the associations of demographic and anthropomorphic variables with TPDT.
  
  
  METHODS
  Healthy individuals (n = 79) across four decades (Group-I:18-29; Group-II:30-39; Group-III:40-49; and Group-IV:50-59years) were recruited. A mechanical calliper tool was used to determine the low back TPDT (mm) using an adaptive staircase method. Descriptive statistics were calculated for TPDT for each age group. Paired t-tests (p ≤ 0.05) were used to assess within group differences in TPDT between body sides. Univariate and weighted least squared linear regression analyses were performed to investigate associations between TPDT estimates and demographics, and body mass index (BMI), waist hip ratio (WHR).
  
  
  RESULTS
  Mean (SD) age = 38.3(12.2); 55 female; and 73 right lower limb dominant. Mean (SD) TPDT threshold for all age groups: right = 67.3(15.6), and left = 65.7(15.4). No significant differences between left and right sides of the low back except in group-IV (mean difference:5.6[0.7-10.5]; P = 0.028). A total of 18% of TPDT variance (adjusted R(2) = 0.183; β = 0.6; p = ≤0.001) of low back regions was explained by age with BMI and WHR weighted independently.
  
  
  CONCLUSIONS
  Age, BMI, and WHR were independently associated with TPDT of the low back, and the influence of age was significantly influenced by obesity indices.
authors.affiliation: Centre for Health, Activity & Rehabilitation Research, School of Physiotherapy, University of Otago, 325 Great King Street, Dunedin 9016, New Zealand.
authors.forename: Carrie
authors.initials: C
authors.lastname: Falling
authors.affiliation: Centre for Health, Activity & Rehabilitation Research, School of Physiotherapy, University of Otago, 325 Great King Street, Dunedin 9016, New Zealand. Electronic address: ramakrishnan.mani@otago.ac.nz.
authors.forename: Ramakrishnan
authors.initials: R
authors.lastname: Mani
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000375:Aging / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000209:etiology*; D008161:Lumbosacral Region / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D012016:Reference Values; D014110:Touch / Q000502:physiology*; D055815:Young Adult
keywords: Lumbar spine; Obesity; Reference values; Tactile acuity