Anthropometric measurements and growth as predictors of low-back pain: a cohort study of children followed up from the age of 11 to 22 years.

Body height is an alleged risk factor for low-back pain (LBP) in adulthood, but its importance is obscure during childhood and adolescence. We studied growth for its association with the incidence of LBP in a population study of 430 children who were examined five times: at the age 11,12,13,14 and 22 years. Body height and weight and the degrees of trunk asymmetry, thoracic kyphosis and lumbar lordosis were measured at every examination. The history of LBP was obtained by a structured questionnaire at the ages of 14 and 22 years. The incidence of LBP was defined as pain, which occurred on eight or more days during the past year among those 338 children who had been free from LBP until 14 years of age. Growth of body height between 11 years and 14 years of age predicted the incidence of LBP. Adjusted for sex, the odds ratio (with 95% confidence interval) per an increment of one SD (4.3 cm) was 1.32 (1.06--1.65), the P value for trend being 0.03. Growth after 14 years of age was inversely related to the incidence of LBP, but the association did not reach statistical significance (P for trend=0.06). Other anthropometric measurements or their changes were not found to predict LBP. Our results are not compatible with the old myth that spinal growth actually contributes to LBP. But abundant growth in early adolescence may be a risk factor for subsequent LBP.