The relationships between physical activity, lumbar multifidus muscle morphology, and low back pain from childhood to early adulthood: a 12-year longitudinal study

Abstract

We investigated the longitudinal associations between physical activity (PA), lumbar multifidus morphology, and impactful low back pain (LBP) in young people. Nine-year-old children were recruited from 25 primary schools and followed up at age 13, 16, and 21 years. We measured PA with accelerometers at age 9, 13, and 16; quantified patterns of lumbar multifidus intramuscular adipose tissue (IMAT) change from 13 to 16 years using magnetic resonance imaging; and recorded LBP and its impact with standardised questionnaires and interviews. Associations were examined with crude and adjusted logistic or multinomial models and reported with odds ratios (OR) or relative risk ratios (RRR). We included data from 364 children (mean[SD] age = 9.7[.4] years). PA behaviour was not associated with LBP. Having persistently high IMAT levels at age 13 and 16 was associated with greater odds of LBP (OR[95% CI] = 2.98[1.17 to 7.58]). Increased time in moderate and vigorous intensity PA was associated with a lower risk of higher IMAT patterns (RRR[95% CI] = .67[.46 to .96] to .74[.55 to 1.00]). All associations became non-significant after adjusting for sex and body mass index (BMI). Future studies investigating the relationships between PA behaviour, lumbar multifidus IMAT, and impactful LBP should account for potential confounding by sex and BMI.

Spinal degeneration and lumbar multifidus muscle quality may independently affect clinical outcomes in patients conservatively managed for low back or leg pain

“…Regarding LMM quality and disability, we included the most common confounders assessed in the related literature, but due to data limitations, we were unable to measure for potential confounding relating to physical activity. However, the role of physical activity in LMM quality and disability analysis is unclear, with recent studies indicating that physical activity in general was not a confounder for, or associated with, LMM morphology in adults or children with LBP 18 , 20 . No studies investigating different levels of physical activity as a confounder between LMM morphology and disability were identified.…”

“…The absence of a relationship between LMM quality and changes in LBP intensity found in our study agrees with findings from other longitudinal studies looking at a diverse collection of muscle and LBP outcome parameters. These have included comparisons of: intramuscular fat in childhood at L4 and L5 (combined) with the likelihood of developing LBP in early adulthood 18 ; the CSA, functional CSA, intramuscular fat, and muscle asymmetry at L3/4 and L5/S1 with changes in frequency and intensity of LBP 19 , 20 ; the highest percentage of intramuscular fat at L4 or L5 as a predictor of future LBP 21 ; the CSA at L3 and L5 as a prognostic indicator of LBP chronicity 22 ; and, the CSA at L3, L4, and L5 as predictors of LBP intensity 7 . These longitudinal studies have evaluated over 1,400 participants from Finnish, Danish, and Korean populations, comparing the standard static measures of L3/4 through L5/S1 LMM morphology to a wide variety of LBP outcome measures, with none demonstrating predictive, prognostic, or causative relationships between LMM morphology and LBP outcomes.…”

“…Longitudinal studies investigating the relationship between LMM morphology and low back-related clinical presentations/outcomes 7 , 18 – 22 , have not shown clear associative or predictive relationships between LMM morphology and back or leg pain, particularly after accounting for age, sex, and/or BMI. One study did, however, note an association between increased multifidus cross-sectional area (CSA) and improved 12-month disability outcomes 7 .…”

Paraspinal Muscle Changes in Individuals with and without Chronic Low Back Pain over a 4-Month Period: A Longitudinal MRI Study

“…While a few studies explored morphological changes in paraspinal musculature in healthy individuals and those with LBP, we are only aware of three longitudinal studies investigating the natural progression (i.e., without intervention) of paraspinal muscle changes [ 3 , 11 , 12 ]. One study investigated LM intramuscular adipose tissue in 40-year-olds over a nine-year period, finding some cross-sectional associations between severe and moderate LM intramuscular adipose tissue and the presence of LBP and leg pain but no longitudinal associations [ 11 ].…”

“…One study investigated LM intramuscular adipose tissue in 40-year-olds over a nine-year period, finding some cross-sectional associations between severe and moderate LM intramuscular adipose tissue and the presence of LBP and leg pain but no longitudinal associations [ 11 ]. A second study investigated the relationship between the presence of LM intramuscular adipose tissue and the effects of physical activity on developing LBP in children over a 12-year period, finding all associations to be non-significant after adjusting for sex and BMI [ 12 ]. A 15-year study on male twins found similar morphological changes in the LM and ES over time.…”