Longitudinal study about low back pain, mental health, and access to healthcare system during COVID-19 pandemic: protocol of an ambispective cohort

This study aims to investigate the effects of physical activity before, during, and after social distancing due to the COVID-19 pandemic on low back pain (LBP), mental health and healthcare access. The PAMPA Cohort ( P rospective Study A bout M ental and P hysical He a lth) is a state-level ambispective longitudinal observational study that will be conducted in Rio Grande do Sul, Brazil. An online-based questionnaire will be used to assess LBP, mental health, healthcare access and physical activity at four time points: 1) pre-COVID-19 social distancing, 2) during COVID-19 social distancing, 3) 6 months and 4) 12 months after baseline. A proportional sample size calculation was conducted, and the final sample size was estimated in 1,767 people, distributed in seven state regions. Participants will be recruited by a four-arm approach: contact with universities, social media, local media and personal contacts. Descriptive analyzes will be reported as mean or proportion and respective 95% confidence interval (CI), when appropriate. Comparison between pre- and during COVID-19 social distancing, and after baseline assessments will be performed using two-way ANOVA with repeated measures. Proportions will be compared by Chi-squared test.