Reference intervals and sources of variation of pressure pain threshold for quantitative sensory testing in a Japanese population

AbstractQuantitative sensory testing (QST) is useful when analysing musculoskeletal pain disorders. A handheld algometer is most commonly used for pressure pain threshold (PPT) tests. However, reference intervals for PPTs are not elucidated. We assessed reference intervals of PPTs for QST in 158 healthy adult Japanese (73 females, 85 males) with no history of musculoskeletal or neurological problems. A handheld algometer was used to record PPT at five different assessment sites on the body: lumbar paravertebral muscle (PVM), musculus gluteus maximus (MGM), quadriceps (QC), tibialis anterior muscle (TA), and anterior talofibular ligament (TL). Multiple regression analysis (MRA) was performed to explore sources of variation of PPT according to sex, age, body mass index (BMI), UCLA Activity Level Rating (ALR), and Tegner Activity Score. Reference intervals were determined parametrically by Gaussian transformation of PPT values using the two-parameter Box-Cox formula. MRA results revealed that age was significantly associated with PPT-PVM in males and with PPT-PVM and PPT-MGM in females. In females, BMI showed significant positive correlation with PPT-TL, and ALR reflecting daily activities also showed significant positive association with PPT-TA and PPT-TL. Site-specific reference intervals of PPTs for Japanese are of practical relevance in fields of pain research using a handheld algometer.