Are people with chronic low back pain meeting the physical activity guidelines? A co-twin control study

Abstract Background Despite a large amount of research investigating physical activity (PA) levels in people with chronic low back pain (LBP), no study has investigated whether people with chronic LBP are meeting the World Health Organization (WHO) PA guidelines. Furthermore, with genetics and the early shared environment substantially influencing the presence of LBP and PA engagement, these factors could confound the association between LBP and PA and need to be controlled for. Purpose This study aimed to investigate the association between chronic LBP and meeting the PA guidelines, while controlling for the effects of genetics and early shared environment. Design This is a cross-sectional co-twin control study. Patient Sample A cross-sectional analysis was performed on 1,588 twins from the Murcia Twin Registry in Spain with available data on LBP and PA from the 2013 data collection wave. Outcome Measures The exposure and outcome variables in our study were self-reported. Twins reporting a history of chronic LBP were asked follow-up questions to inform on the presence of recent LBP (within the past 4 weeks), previous LBP (no pain within the past 4 weeks), and persistent LBP (no pain-free month in the last 6 months). These were our exposure variables. Our outcome variable was meeting the WHO PA guidelines, which involved at least 75 minutes of vigorous-intensity PA, or at least 150 minutes of moderate-intensity PA per week. Methods To investigate the association between chronic LBP and meeting the PA guidelines, we first performed a multivariate logistic regression on the total sample of twins. Co-variables entered the model if the univariate association between the co-variable, and both the exposure and the outcome reached a significance of p