Introduction: Obese patients have a high prevalence of painful musculoskeletal disorders that may decrease after massive weight loss. Pain thresholds may be different in obese participants.
Objectives: To assess the sensitivity and pain detection thresholds, through the application of an electrical sensitivity, before and after massive weight loss, and to compare the thresholds obtained with those in a control population.
Methods: The sensitivity and pain detection thresholds obtained in participants subjected to electrical stimulation were determined in 31 obese individuals (age: 40.3 ± 10.5 y) before (body mass index: 45.7 ± 6.8 kg/m) and 6 months after a mean weight loss of 32 kg induced by gastric bypass. The results obtained were compared with those for 49 nonobese control participants (38.5 ± 11.2 y; body mass index: 22.6 ± 2.6 kg/m). Body composition and metabolic biomarkers, such as leptin, adiponectin, insulin, and interleukin 6, were assessed and single-nucleotide polymorphisms of the mu opioid receptor [OPRM1 (c.118A > G) and COMT (p.Val158Met)] were genotyped in obese patients.
Results: Sensitivity and pain detection thresholds (3.9 ± 1.1; 11.6 ± 6.0) were significantly higher in obese than in nonobese participants (3.1 ± 1.1; 6.0 ± 3.0), respectively (P < 0.0001), and were not affected by drastic weight loss (mean change: 32 kg). Pain thresholds in obese participants were not correlated with any of the clinical and biological variables studied. The obese participants in the highest quartile for both sensitivity and pain detection thresholds were significantly older than those in the lowest quartile.
Conclusions: Further studies are required to explore sensory dysfunction in obese individuals and to investigate the implications of this dysfunction for pain management.