AB0214 ASSOCIATION BETWEEN ACCELEROMETER-MEASURED DAILY STEP COUNT AND INCIDENT RHEUMATOID ARTHRITIS: A PROSPECTIVE COHORT STUDY IN THE UK BIOBANK
Authors: D. Mcgagh, A. Acquah, L. Portas, C. Zisou, A. Shreves, C. Harper, S. Fenton, A. Doherty, L. C. Coates
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Existing evidence on the association between physical activity and rheumatoid arthritis (RA) remains conflicted due to a reliance on self-reported physical activity questionnaires, which are crude and prone to recall bias. Wearable devices, such as accelerometers can continuously and more objectively measure physical activity level. <h3>Objectives:</h3> We aimed to examine the dose-response association between accelerometer-measured daily step count and incident rheumatoid arthritis. <h3>Methods:</h3> This prospective cohort study was based on wrist-worn accelerometer data from the UK Biobank, where participants wore a device for seven days. Participants with prevalent inflammatory arthritis (RA, psoriatic arthritis or ankylosing spondylitis) were excluded. Daily steps were computed using a validated hybrid self-supervised machine learning step detection algorithm. Physical activity was characterised as median daily step count over a seven-day period, as a continuous measurement, in quarters of steps (&lt;6818, 6818-9055, 9056-11659, &gt;11659 daily steps) and per 1000 step increase. Incident RA cases were identified via record linkage with hospital inpatient data. Cox proportional hazards models were utilised to investigate the association between daily step count and incident RA adjusting for sociodemographic and lifestyle factors. Subgroup analyses were conducted to explore the association per 1000 step increase and incident RA, stratified by sex, age group (40-49, 50-59, 60-69 and 70-79) and body mass index (BMI by categories: &lt;25, 25-29.9, &gt;30 kg/m2). Sensitivity analyses removing RA diagnoses within 2 and 4 years of accelerometer wear and further adjusting for BMI were conducted. <h3>Results:</h3> Amongst 91,069 participants aged 62.3 (SD 7.8) years and with a median follow-up of 7.9 years, there were 629 incident RA cases (87.4 cases per 100,000 person years). Higher median daily step count was associated with lower risk of incident RA, and this association was approximately inverse log-linear. Compared to individuals in the lowest quarter (&lt;6818 daily steps), higher median daily step count was associated with a lower risk of incident RA, with individuals in the highest quarter (&gt;11659 daily steps) having a 45% lower risk of RA (HR 0.55, [95% confidence interval [CI] 0.44-0.68]) (Figure 1A). There was lower risk of RA across both the second (6818-9055 steps) (HR 0.77 [0.65-0.95]) and third (9056-11659 steps) (HR 0.72 [0.60 – 0.86]) quarters of daily steps when compared to the lowest quarter. Per 1000 increase in steps, we observed a 5% lower risk of RA (HR 0.95 [CI 0.93-0.97]). Additional analyses where all diagnoses of RA within 2 and 4 years of accelerometer wear were removed and addition of BMI into the primary model had little impact on the associations. In subgroup analyses, a 1000 step increase per day was associated with a lower risk for individuals in the overweight and obese BMI categories, age bands 50-59, 60-69 and 70-79 and in females (Figure 1C). <h3>Conclusion:</h3> In this cohort study of UK Biobank participants, a higher daily step count was associated with a lower risk of developing RA. The findings highlight that even incremental increases in daily steps are associated with a lower risk of RA, notably in specific subgroups such as those with higher BMI, older age groups, and females. Further studies are needed to explore the association between physical activity and incident RA in at-risk individuals. <h3>REFERENCES:</h3> <b>NIL.</b> <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> Dylan McGagh: None declared, Aidan. Acquah GlaxoSmithKline, Laura Portas: None declared, Charilaos Zisou: None declared, Alaina Shreves: None declared, Charlie Harper: None declared, Sally Fenton: None declared, Aiden Doherty: None declared, Laura C. Coates AbbVie, Amgen, Biogen, Celgene, Eli Lilly, Galapagos, Gilead, GSK, Janssen, Medac, Novartis, Pfizer and UCB, AbbVie, Amgen, Boehringer Ingelheim, Bristol Myers Squibb, Celgene, Eli Lilly, Gilead, Galapagos, Janssen, Moonlake, Novartis, Pfizer and UCB, AbbVie, Amgen, Celgene, Eli Lilly, Janssen, Novartis, Pfizer and UCB.