Associations Between Symptoms and Quality of Life in Lumbar Degenerative Disease and Cognitive Dysfunction in a Japanese Community: A Cross-sectional Study

Abstract Background: Lumbar degenerative disease (LDD) and dementia are increasing in super-aging societies and are both related to physical dysfunction and pain. However, the relationship between these diseases remains unclear. This cross-sectional study aimed to investigate the rate of comorbidity of lumbar spinal stenosis (LSS) and mild cognitive impairment (MCI) by age and sex and clarify the association between LSS presence, LDD symptoms, quality of life (QOL) related to low back pain, and cognitive impairment in a Japanese population.Methods: We enrolled 1097 participants (men 437; women 660; mean age 54.6 years) from a medical checkup program. LSS was diagnosed using a self-administered questionnaire, and LDD symptoms were evaluated using visual analog scale (VAS: low back pain, pain, numbness of the lower limb). QOL related to low back pain was evaluated using the Japanese Orthopedic Association Back-Pain Evaluation Questionnaire (JOABPEQ: pain, lumbar function, and gait function), and Kellgren-Lawrence grading was performed to evaluate lumbar degeneration using lateral radiographs of the lumbar spine. Cognitive function was measured using the Mini Mental State Examination (MMSE), and we defined MCI as a summary score of MMSE £27. Logistic and multiple liner regression analyses were performed to analyze the association between MCI, summary score of MMSE and LSS factors.Results: The comorbidity rate of MCI and LSS was 0.9% in men and 0.7% in women. It was 2.1% in those aged ³65 years in both sexes, and this rate increased with age. Lumbar function in JOABPEQ (OR 0.979, 95% CI 0.961 to 0.998) and lower limb pain in VAS (OR 1.020, 95% CI 1.002 to 1.039) were associated with MCI in men. The presence of LSS, lumbar function, and gait function in JOABPEQ were associated with MMSE in both sexes, while lower limb numbness and pain in VAS were associated with MMSE in men.Conclusion: The comorbidity rate of LSS and MCI increased with age. The presence of LSS, certain symptoms of LDD, and deterioration of QOL due to low back pain were related to cognitive dysfunction. Treatment of LDD could help to improve both LDS symptoms and cognitive dysfunction.