R. Goto1, T. Isa1, K. Horibe1, R. Kawaharada1, Y. Tsuboi1,2, K. Nakatsuka1, K. Uchida1, K. Saeki1, E. Perrein1, R. Ono1
1Graduate School of Health Sciences, Kobe University, Public Health, Kobe, Japan, 2Back Tech Inc., Kyoto, Japan
Background: There has been a substantial decline in cardiorespiratory fitness (CRF) of children since the 1980s. Thus, it is needed to clarify the cause of decline in CRF. The ownership rate of mobile phones has been increasing among children. Although mobile phone use is negatively associated with CRF, there are few evidences that show the longitudinal association of mobile phone use with CRF of children. Furthermore, there are few studies that investigate the relationship between screen time and CRF during the maximum development age of CRF (boy, 11.4 years; girl, 10.5 years).
Purpose: To investigate the effect of mobile phone use on CRF of children aged 9-12 years old during a 2-year period.
Methods: Our study design was a 2-year longitudinal study using two datasets. We invited children aged 9-10 years old from two public schools in Kobe, Japan. We assessed CRF by 20-m shuttle run test at baseline and at follow-up, 2 years later. We divided the children into tertiles based on the records of the 20-m shuttle run test at baseline and follow-up for each gender. We classified the children as having a “Poor CRF” if they went down the tertile or maintained the lowest tertile or “Good CRF” if they went up the tertile or maintained the middle or highest tertile. We assessed mobile phone use by a self-reported questionnaire at baseline and classified children as using <2h/day or ≥2h/day. We used univariate logistic regression analysis to investigate the effect of mobile phone use from baseline to 2 years later in CRF, and we used multivariate logistic regression analysis adjusting for gender, physical activity, and dataset group.
Results: This study included 175 children (88 boys; mean age 9.5 years at baseline). We classified children as having “Good CRF” for 99 children, and ≥2h/day for 23 children. Among children who were classified as ≥2h/day, 8 children had “Good CRF” and 15 children had “Poor CRF”. Children who were classified as ≥2h/day had lower odds of “Good CRF” (odds ratio = 0.36; 95% confidence interval = 0.15-0.90). After adjusting for confounders, children who were classified as ≥2h/day had lower odds of “Good CRF” (odds ratio = 0.33; 95% confidence interval = 0.12-0.91).
Conclusion(s): This study demonstrated the effect of mobile phone use on CRF in fourth grade on a 2-years period. This is the first longitudinal study to show that 2 hours or more of mobile phone use had a negative impact on CRF development of children.
Implications: This study suggested that limiting excessive mobile phone use is important for the healthy development of CRF of children aged 9-12 years old.
Funding, acknowledgements: Study founded by the Sasakawa Sports Research Grant from Sasakawa Sports Foundation [grant number 180B3-042].
Keywords: children, cardiorespiratory fitness, mobile phone use
Topic: Health promotion & wellbeing/healthy ageing/physical activity
Did this work require ethics approval? Yes
Institution: Kobe University Graduate School of Health Science
Committee: Research Ethics Committee
Ethics number: 545-3
All authors, affiliations and abstracts have been published as submitted.
