Centre for Exercise, Nutrition & Health Sciences, School for Policy Studies, University of Bristol, 8 Priory Road, Bristol, BS8 1TZ, UK.
Department for Health, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
Int J Behav Nutr Phys Act. 2018 Feb 21;15(1):18. doi: 10.1186/s12966-018-0653-9.
Physical activity in children is associated with better physical and mental health but many children do not meet physical activity guidelines. Friendship groups are potentially an important influence on children's physical activity and sedentary time. This paper examines the association between children of physical activity and sedentary time in school-based same-sex friendship networks, for both moderate-to-vigorous intensity physical activity (MVPA) and sedentary time. Moreover, considering the methodological challenges of conducting and interpreting these analyses, we provide examples of how to analyse these data and interpret results to encourage further work in the area.
Accelerometer data for 1223 children, aged 8-9 years, were collected in 2015-2016 and analysed in 2017. Mean accelerometer minutes of MVPA and sedentary time were calculated. Children named up to four school friends and same-sex school-based friendship networks were constructed. Network models, which include correlation between friends, were fitted by sex.
Both MVPA and sedentary time were found to be associated via the friendship networks, for both boys and girls. The network autocorrelation was 0.21 (95% CI: 0.15 to 0.26) for boys' MVPA, and 0.14 (95% CI: 0.07 to 0.21) for sedentary time. Network autocorrelation between girls was weaker, with 0.13 (95% CI: 0.06 to 0.19) for MVPA and 0.11 (95% CI: 0.05 to 0.17) for sedentary time.
Physical activity and sedentary time of boys and girls are associated with the physical activity and sedentary time respectively of others within same-sex friendship networks, and these associations are comparable to other known factors. In this study, the correlation between friends was stronger for boys than girls, and stronger for MVPA than for sedentary time. These findings suggest that friendship networks play a part in understanding children's physical activity and sedentary time and could play a valuable role in developing effective interventions.
儿童的身体活动与更好的身心健康有关，但许多儿童不符合身体活动指南。友谊群体可能是影响儿童身体活动和久坐时间的重要因素。本文研究了基于学校的同性友谊网络中儿童身体活动和久坐时间之间的关系，包括中等到剧烈强度的身体活动（MVPA）和久坐时间。此外，考虑到进行和解释这些分析的方法学挑战，我们提供了分析这些数据和解释结果的示例，以鼓励在该领域进一步开展工作。
2015-2016 年收集了 1223 名 8-9 岁儿童的加速度计数据，并于 2017 年进行了分析。计算了平均加速度计分钟的 MVPA 和久坐时间。孩子们最多可以命名四个学校朋友，并构建了基于学校的同性友谊网络。按性别拟合包括朋友之间相关性的网络模型。
男孩和女孩的 MVPA 和久坐时间都通过友谊网络相互关联。男孩 MVPA 的网络自相关系数为 0.21（95%置信区间：0.15 至 0.26），而久坐时间为 0.14（95%置信区间：0.07 至 0.21）。女孩的网络自相关较弱，MVPA 为 0.13（95%置信区间：0.06 至 0.19），久坐时间为 0.11（95%置信区间：0.05 至 0.17）。
男孩和女孩的身体活动和久坐时间分别与同性友谊网络中其他人的身体活动和久坐时间相关，这些关联与其他已知因素相当。在这项研究中，朋友之间的相关性在男孩中比女孩中更强，在 MVPA 中比在久坐时间中更强。这些发现表明，友谊网络在理解儿童的身体活动和久坐时间方面发挥了作用，并可能在制定有效的干预措施方面发挥宝贵作用。
