Relationship between autonomic nervous system function and bone mineral density in type 1 diabetic individuals
Date
2006
Authors
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Publisher
University of Delaware
Abstract
Objective: To determine the influence of autonomic nervous system function (ANSF) on bone mineral density (BMD) in type 1 diabetic individuals. Research Design and Methods: Sixteen subjects were grouped based on normal (n = 11, mean age = 38.7 ± 10.5 years, mean duration of diabetes = 20.1 ± 14.3 years, mean weight = 77.6 ± 16.2 kg) or abnormal (n = 5, mean age 50.4 ± 9.3 years, mean duration of diabetes = 32.2 ± 14.1 years, mean weight = 73.9 ± 7.3 kg) ANSF as determined by measurement of the mean circular resultant (MCR) of heart rate variability. Additional measures of ANSF included the following: expiration to inspiration ratio during deep breathing, valsalva maneuver, heart rate and blood pressure response to standing, power spectral density analysis of heart rate response to deep breathing, normal breathing, and paced breathing; and spontaneous baroreflex sensitivity during normal breathing and paced breathing. Past physical activity was measured via questionnaire. Current physical activity was measured for three days by an accelerometer. Participants also completed food records on the days that they donned accelerometers. Dual energy x-ray absorptiometry assessed BMD and bone mineral content (BMC) at the left hip, lumbar spine, and total body. Results: There was no significant difference in BMD or BMC at the left hip (p = 0.635, p = 0.119), lumbar spine (p = 0.722, p = 0.572), or total body (p = 0.654, p = 0.606) between type 1 diabetic individuals with normal (mean MCR = 56.82 ± 21.70) and abnormal (mean MCR = 11.62 ± 5.88) ANSF. Measures of physical activity and diet were also not different between groups. Serum creatinine was different between groups (p = 0.022). Conclusions: These data suggest that there is no difference in BMD between type 1 diabetic individuals with normal and abnormal ANSF. The present findings were likely hampered by an inadequate sample size.