Salivary α-amylase Activity and s-IgA Levels Could be Taken as a Measure of Physiological Stress in Wheelchair-dependent Persons with Physical Disabilities and Without Disability Middle-aged Persons

Abstract

Aims: The s-IgA/total protein ratio and α-amylase activity in saliva have been used as indexes of stress because they change according to the physiological stress. Using both indexes, this study aimed to compare the circadian rhythm of stress levels in wheelchair-dependent persons with congenital physical disabilities with those in without disability middle-aged persons. Study Design: Physiological stress was measured by biochemical analysis of the saliva. Place and Duration of Study: Collection of saliva was performed at participant’s house by own self and with the care worker. Biochemical analysis was carried out at Osaka Prefecture University, Osaka, Japan, from September 2012 to March 2013. Methodology: Subjects were 12 wheelchair-dependent persons with congenital physical disabilities and 12 without disability persons of the same generation. Saliva was collected in the morning (on awakening, after breakfast and before lunch), in the afternoon (after lunch, at 15:00 and before dinner) and at night (after dinner and at bedtime). The s-IgA in saliva supernatant was determined by ELISA method. A difference among mean values of the s-IgA/total protein ratio and α-amylase activity was examined by two-way analysis of variance (ANOVA) (disability presence × collection period), with only one-way pairing (collection period). Results: The s-IgA/protein ratio was significantly affected by the period factor; results of the post hoc test revealed that the ratio was higher in the morning than in the afternoon and at night in the both groups. A significant interaction was observed with regard to α-amylase activity; results of the post hoc test revealed that α-amylase activity in the afternoon and at night was higher in the disability group than in the without disability group, and in the disability group, the activity was lower in the morning than in the afternoon and at night. Conclusion: Wheelchair-dependent persons with congenital physical disabilities have higher physiological stresses and greater circadian rhythm fluctuation than without disability middle-aged persons.