| Study | Study Participants [Sample size (M/F; age)] | Classification of Obesity | Noxious Stimuli | Outcome Measure |
Data Obese [Mean+SD] |
Data Non-Obese [Mean+SD] |
Difference P value |
Authors’ Conclusion |
Methodological Quality Score (%) Reviewers’ Comment |
|---|---|---|---|---|---|---|---|---|---|
| Zahorska-Markiewicz et al. (1983) [25] | N = 48(0/48; 16-52 years) N obese = 20 (0/20) N non-obese = 20 (0/20) N underweight = 8(0/8) |
Percentage excess against ideal body weight from Metropolitan Life Insurance Tables Mean % excess obese = 87.9%, non-obese = 1.6% and underweight = -10.1% |
Transcutaneous electrical stimulation of forearm with amplitude increasing from 0-18mA | Pain Threshold | Forearm = 13.03+3.27mA Arm = 8.83+4.31mA |
Forearm = 7.55+3.76mA Arm = 5.56+2.32mA Forearm [underweight] = 5.88+3.18mA Arm [underweight] = 6.1+5.34mA |
Forearm <0.001 Arm P=<0.01 |
Obese less sensitive to noxious stimuli than non-obese | 32% Positive correlation between pain threshold and body weight, and weight excess |
| Zahorska-Markiewicz et al. (1988) [26] | N = 49(0/49; 24-61 years) N obese = 35(0/35) N non-obese = 14(0/14) |
Percentage excess against ideal body weight from Metropolitan Life Insurance Tables Mean % excess obese = 64.5%, non-obese = not reported |
Transcutaneous electrical stimulation of forearm with amplitude increasing from 0-20mAmin-1 at various time points throughout the day and over a 4 week weight reducing treatment phase |
Pain Threshold [1st measure taken at 7am pre-treatment] | 12.5+4.4mA | 7.3+3.8mA | <0.001 | Obese less sensitive to noxious stimuli than non-obese | 36% Main focus of study was to investigate relationship between circadian rhythms and electrical pain threshold during weight-reducing treatment |
| Maffiuletti et al. (2011) [28] | N = 67 (34/33) N obese = 32(M/F not reported) N ‘non-obese’ =35(M/F not reported) |
BMI Obese >30kg/m2 |
Transcutaneous electrical stimulation of quadriceps muscle to elicit muscle contraction | Pain Intensity (100mm VAS) of ‘highest tolerated threshold’ to elicit contraction | M=46+27mm F=56+26mm |
M=43+26mm F=48+27mm |
Not significantly different” [P value not reported] | No difference in sensitivity to noxious stimuli between obese and non-obese individuals | 66% Conclusion “Current tolerance to motor stimulation was reduced in obese individuals … whereas pain was not influenced by gender or obesity” |