Swiss Tropical and Public Health Institute, Allschwil, Switzerland.
University of Basel, Basel, Switzerland.
PLoS One. 2024 May 31;19(5):e0298890. doi: 10.1371/journal.pone.0298890. eCollection 2024.
Quality of life (QoL) is an important health indicator among children and adolescents. Evidence on the effect of physical activity (PA)-related behaviors on QoL among youth remains inconsistent. Conventional accelerometer-derived PA metrics and guidelines with a focus on whole weeks may not adequately characterize QoL relevant PA behavior.
This study aims to a) identify clusters of accelerometer-derived PA profiles during weekend days among children and adolescents living in Switzerland, b) assess their cross-sectional and predictive association with overall QoL and its dimensions, and c) investigate whether the associations of QoL with the newly identified clusters persist upon adjustment for the commonly used PA metrics moderate-to-vigorous physical activity (MVPA) and time spent in sedentary behavior (SB).
The population-based Swiss children's Objectively measured PHYsical Activity (SOPHYA) cohort among children and adolescents aged 6 to 16 years was initiated at baseline in 2013. PA and QoL information was obtained twice over a five-year follow-up period. The primary endpoint is the overall QoL score and its six dimension scores obtained by KINDL® questionnaire. The primary predictor is the cluster membership of accelerometer-derived weekend PA profile. Clusters were obtained by applying the k-medoid algorithm to the distance matrix of profiles obtained by pairwise alignments of PA time series using the Dynamic Time Warping (DTW) algorithm. Secondary predictors are accelerometer-derived conventional PA metrics MVPA and SB from two combined weekend days. Linear regression models were applied to assess a) the cross-sectional association between PA cluster membership and QoL at baseline and b) the predictive association between PA cluster membership at baseline and QoL at follow-up, adjusting for baseline QoL.
The study sample for deriving PA profile clusters consisted of 51.4% girls and had an average age of 10.9 [SD 2.5] years). The elbow and silhouette methods indicated that weekend PA profiles are best classified in two or four clusters. The most differentiating characteristic for the two-clusters classification ("lower activity" and "high activity"), and the four-clusters classification ("inactive", "low activity", "medium activity", and "high activity"), respectively was the participant's mean counts per 15-seconds epoch. Participants assigned to high activity clusters were younger and more often male. Neither the clustered PA profiles nor MVPA or SB were cross-sectionally or predictively associated with overall QoL. The only association of a conventional PA metrics with QoL while adjusting for cluster membership was observed between MVPA during the weekend days and social well-being with a mean score difference of 2.4 (95%CI: 0.3 to 4.5; p = 0.025).
The absence of strong associations of PA metrics for the weekend with QoL, except for the positive association between MVPA during the weekend days and social well-being, is in line with results from two randomized studies not showing efficacy of PA interventions on youth QoL. But because PA decreases with age, its promotion and relevance to QoL remain important research topics. Larger longitudinal study samples with more than two follow-up time points of children and adolescents are needed to derive new novel accelerometer-derived PA profiles and to associate them with QoL dimensions.
生活质量（QoL）是儿童和青少年的重要健康指标。关于体力活动（PA）相关行为对年轻人生活质量影响的证据仍然不一致。传统的加速度计衍生的 PA 指标和以整周为重点的指南可能无法充分描述与生活质量相关的 PA 行为。
本研究旨在：a）确定瑞士居住的儿童和青少年在周末的加速度计衍生 PA 谱的聚类，b）评估它们与整体 QoL 及其维度的横断面和预测关联，c）调查在调整常用 PA 指标中等到剧烈体力活动（MVPA）和久坐行为（SB）时间后，与新确定的聚类相关的 QoL 关联是否仍然存在。
基于人群的瑞士儿童客观测量 PHYsical Activity（SOPHYA）队列，包括 6 至 16 岁的儿童和青少年，于 2013 年在基线开始。在五年的随访期间，两次获得 PA 和 QoL 信息。主要终点是通过 KINDL®问卷获得的整体 QoL 评分及其六个维度评分。主要预测因子是加速度计衍生的周末 PA 图谱的聚类成员身份。通过应用 k-中值算法对使用动态时间 warping（DTW）算法对 PA 时间序列进行两两对齐后获得的图谱的距离矩阵进行聚类。次要预测因子是从两个合并的周末获得的加速度计衍生的常规 PA 指标 MVPA 和 SB。应用线性回归模型评估：a）PA 聚类成员与基线 QoL 之间的横断面关联，b）PA 聚类成员在基线和随访时与 QoL 的预测关联，调整基线 QoL。
用于推导 PA 谱聚类的研究样本包括 51.4%的女孩，平均年龄为 10.9 [SD 2.5] 岁）。肘部和轮廓线方法表明，周末 PA 谱最好分为两或四个聚类。两个聚类分类（“低活动”和“高活动”）和四个聚类分类（“不活动”、“低活动”、“中活动”和“高活动”）的最具区别特征分别是参与者的平均每 15 秒计数。被分配到高活动聚类的参与者年龄较小，男性居多。聚类 PA 谱以及 MVPA 或 SB 既没有与整体 QoL 进行横断面关联，也没有进行预测关联。在调整聚类成员身份后，唯一与常规 PA 指标与 QoL 相关的是周末期间的 MVPA 与社会幸福感之间存在正相关，平均评分差异为 2.4（95%CI：0.3 至 4.5；p = 0.025）。
周末 PA 指标与 QoL 之间没有很强的关联，除了周末期间的 MVPA 与社会幸福感之间的积极关联外，这与两项未显示 PA 干预对年轻人生活质量疗效的随机研究结果一致。但是，由于 PA 随年龄增长而下降，因此促进和重视 PA 与 QoL 的相关性仍然是重要的研究课题。需要更大的儿童和青少年纵向研究样本，以便获得新的加速度计衍生的 PA 谱，并将其与 QoL 维度相关联。
