Risk Factors for Neuropathic Pain in Middle-Aged and Elderly People: A Five-Year Longitudinal Cohort in the Yakumo Study

Objective. To determine the risk factors for new neuropathic pain (NeP) after five years in healthy middle-aged and elderly volunteers. Design. Prospective longitudinal cohort study (Yakumo study). Setting. Clinical evaluation in a health checkup. Subjects. A total of 366 people (male N = 146, female N = 220, average age = 63.5 years) who did not have NeP in 2013 were examined. Methods. NeP was diagnosed based on a painDETECT questionnaire score >= 13. Body mass index (BMI), comorbidity, low back pain (LBP), sciatica, physical ability, grip and back muscle strength, osteoporosis, sarcopenia, frailty, spinal alignment, and quality of life (QOL) with the SF36 in 2013 were compared between NeP(+) and NeP(-) subjects in 2018 using multivariate logistic regression analysis. Results. The NeP(+) rate in 2018 was 5.2%, with no significant differences in age and gender. NeP(+) subjects had significantly lower BMI, severe sciatica, poor gait ability, higher rates of osteoporosis and sarcopenia, greater lumbar kyphosis and spinal inclination, and poorer mental health in 2013. Poor gait ability (odds ratio [OR] = 8.05), low BMI (OR = 2.31), lumbar kyphosis (OR = 1.38), low percentage of the young adult mean (OR = 1.15), and low mental QOL (OR = 1.06) were identified as significant and independent risk factors for new NeP after five years. Conclusions. This longitudinal cohort study identified five independent risk factors for development of new NeP after five years, with related factors of spinal inclination, sarcopenia, and sciatica. New NeP may be prevented by intervention or treatment of these factors at an early stage in relatively healthy middle-aged and elderly people.