Occupational biomechanical exposure predicts low back pain in older age among men in the Gazel Cohort

Occupational biomechanical exposures are considered as risk factors for low back pain in the working population. It has also been suggested that their effects persist after retirement. Our objectives were to assess the role of past biomechanical occupational exposure on low back pain in early old age among male participants of the Gazel Cohort. Low back pain for more than 30 days in the past 12 months (LBP30) was assessed in 1996 and 2006 using a French version of the Nordic questionnaire in a subsample of the Gazel Cohort. Logistic regression models were used to study associations between LBP30 in 2006 and past occupational biomechanical exposure, self-reported in 1996, taking into account personal and psychosocial work factors self-reported in 1996, and the date of retirement provided by the company. A multinomial model served to study persistent and new cases, according to LBP30 in 1996. We studied 1,520 men aged 58-67 in 2006, most of them retired. Low back pain for more than 30 days in the past 12 months reported in 2006 was related to occupational biomechanical exposure encountered many years earlier (OR 1.55, 95 % CI 1.05-2.27 for 10-20 years of exposure to bending/twisting, OR 1.71, 95 % CI 1.17-2.49 for > 20 years). These associations appeared specific to low back pain for more than 30 days in the past 12 months which persisted between 1996 and 2006. These results suggest that occupational biomechanical exposure during active life has persistent effects among men in early old age, even for people who left the workforce. They point out the importance of preventive measures at work for better health later and appear relevant for policy-making decisions concerning age at retirement.