Association of decreased physical activity due to the COVID-19 pandemic with new-onset neck pain in survivors of the Great East Japan Earthquake: a prospective cohort study

Objectives The COVID-19 pandemic has forced many people to stay at home and to maintain social distancing. This study aimed to assess the association of reduced physical activity during the COVID-19 pandemic with new onset of neck pain (katakori) among a rural Japanese population living in areas damaged by the Great East Japan Earthquake (GEJE).Design, setting and participants This prospective cohort study has been conducted continuously since 2011 after the GEJE. This study used longitudinal data from 1608 adults who responded to the self-reported questionnaire before and during the COVID-19 pandemic. Changes in physical activity due to the COVID-19 pandemic were categorised into four groups: ‘no change’, ‘decreased by 20%–30%’, ‘decreased by half’ and ‘almost never go out’. Multiple logistic regression analysis was used to estimate the OR and 95% CI of the association between COVID-19 pandemic-related physical inactivity and new-onset neck pain.Results In total, ‘no change’, ‘decreased by 20%–30%’, ‘decreased by half’, and ‘almost never go out’ were reported by 9.2%, 27.7%, 31.2% and 21.9% of respondents, respectively. Among them, 9.8% reported new-onset neck pain. A significantly higher rate of new-onset neck pain was observed in participants who reported ‘decreased by half’ (adjusted OR 1.85, 95% CI 1.04 to 3.30) and who ‘almost never go out’ (adjusted OR 2.13, 95% CI 1.16 to 3.91), compared with those who reported ‘no change.’Conclusions Decreased physical activity has increased due to the COVID-19 pandemic and was significantly associated with new-onset neck pain among GEJE survivors