Combined impact of lifestyle factors on low back pain: A cross-sectional study of over 400,000 Japanese adults

Abstract Background: Many epidemiological studies have indicated the association between low back pain (LBP) and lifestyle factors, such as physical activity, smoking, weight gain, diet, and sleep problems. However, the combined effect of lifestyle factors on LBP has not been adequately investigated. Thus, we aimed to investigate the association between a cluster of unhealthy lifestyle behaviors and LBP using a large cohort of Japanese adults.Methods: We included 419,003 adults aged over 20 years who underwent an annual health checkup between April 2013 and March 2014 in Japan. Information on the following lifestyle factors were collected using the standardized questionnaire recommended by the Ministry of Health, Labour and Welfare in Japan: smoking, alcohol intake, exercise, physical activity, walking speed, weight control, eating habits, and sleep. Each factor was evaluated as a dichotomous variable (1: health risk, 0: no health risk). A lifestyle risk score was calculated by summing the score of each lifestyle factor (range: 0-12) and was categorized into three groups (low, moderate, high). LBP was defined as self-reported LBP under treatment. Logistic regression analysis was conducted to calculate the odds ratio (OR) and 95% confidence interval (CI) for LBP.Results: In multivariate logistic regression analysis, the OR for LBP was significantly higher in the moderate risk score group (adjusted OR: 1.33 [95% CI: 1.23-1.44] in men; 1.40 [95% CI: 1.27-1.54] in women) and the high risk score group (adjusted OR: 1.54 [95% CI: 1.43-1.67] in men; 1.83 [95% CI: 1.64-2.03] in women) than in the low risk score group. A trend of higher risk of LBP associated with higher lifestyle risk score was observed in both sexes (p for trend < 0.001). These results were similar even in subgroup analysis by age (20-39, 40-59, and ≥ 60 years) and body mass index (BMI) (< 18.5, 18.5-24.9, and ≥ 25 kg/m2).