Whedon (2015) in a recent study updated the safety of chiropractic care in the Medicare population age 66-99 years.  The author states "The risk of injury in patients with intervertebral disc disorder with myelopathy was actually reduced, suggesting that this condition is not a risk factor for injury due to chiropractic SM. " (page 269)  They continued by stating, "It is unlikely that chiropractic care is a significant cause of injury in older adults. The lower risk in the chiropractic cohort may suggest to some that chiropractic care is protective against injury in older adults." (page 269)  The also concluded, "We found that chiropractic use is comparatively protective against 1-year declines in function and self-assessed health among Medicare beneficiaries with spine conditions and is also associated with higher satisfaction on measures of follow-up care and with information provided. " (page 548)

Whedon, James M., et al. "Risk of Traumatic Injury Associated With Chiropractic Spinal Manipulation in Medicare Part B Beneficiaries Aged 66 to 99 Years." Spine 40.4 (2015): 264-270.