Age-threshold for increased risk of developing back disorders: prospective cohort with 74 000 individuals from the UK Biobank.

Objective: To investigate the prospective associations between age and the risk of low back disorders (LBD), dorsal disorders (DD), and cervical disorders (CD), and to identify a potential age-threshold for increased risk of back disorders.

Methods: Prospective cohort from the UK Biobank comprising adults with no history of back disorders. We examined different ages and their association with the risk of back disorders derived from diagnoses of hospital registers. Associations were investigated using restricted cubic splines adjusted for sex, racial and ethnic background, tobacco use, Townsend Deprivation Index, alcohol consumption, educational attainment, employment status, self-reported health, diet quality, body mass index, medication use, physical activity, and handgrip strength.

Results: The analytic sample comprised 74,191 participants (mean [SD] age, 55.2 [7.8] years; 57%women) who were followed-up for 7.9 years (IQR = 7.3-8.4). Overall, 3297 (4.3%) cases of incident LBD, 1224 (1.6%) cases of DD, and 792 (1.0%) of CD were documented. The association between age and LBD showed a curvilinear shape with significant higher risk within the range of 61 (hazard ratio [HR] = 1.39 [95%CI,1.02-1.49]) and 70 (HR = 1.71 [95%CI,1.38-2.12]) years (reference:40 years). Similarly, the association of age with DD exhibited a significant curvilinear association within the range of 60 (HR = 1.31 [95%CI,1.01-1.92]) and 70 (HR = 2.74 [95%CI,1.94-3.86]) years. The association between age and CD was not significant.

Conclusions: The risk of LBD and DD, but not CD, increases beyond 60 years of age. Targeting people at this critical age-threshold to prevent risk for LBD and DD may be warranted for future interventions and preventive health programmes.