Ageing and obesity indices influences the tactile acuity of the low back regions: A cross-sectional study

• TPDT reference values for the low back region have been reported.
• Age and obesity indices are associated with low back TPDT estimates.
• Effect of age on TPDT was significantly influenced by obesity indices.
• TPDT side differences were observed only in individuals aged between 50 and 59 years.
• Lower limb dominance was not associated with low back TPDT estimates.

Background and aimsTwo-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.MethodsHealthy 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).ResultsMean (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 R2 = 0.183; β = 0.6; p = ≤0.001) of low back regions was explained by age with BMI and WHR weighted independently.ConclusionsAge, BMI, and WHR were independently associated with TPDT of the low back, and the influence of age was significantly influenced by obesity indices.