Background

Mental wellbeing in adolescents has declined considerably during past decades, making the identification of modifiable risk factors important. Prolonged screen time and insufficient physical activity appear to operate independently and synergistically to increase the risk of poor mental wellbeing in school-aged children. We aimed to examine the gender-stratified dose-dependent and joint associations of screen time and physical activity with mental wellbeing in adolescents.

Methods

We used data from three rounds of Health Behaviour in School-aged Children cross-sectional surveys (2006, 2010, and 2014) from 42 European and North American countries. Survey participants, aged 11 years, 13 years, and 15 years, provided self-reported information by completing an anonymous questionnaire that included items on health indicators and related behaviours. We used the self-reported variables of life satisfaction and psychosomatic complaints as indicators of adolescents' mental wellbeing, combining these with the self-reported discretionary use of screens and engagement in physical activity. We used generalised additive models and multilevel regression modelling to examine the gender-stratified relationships between mental wellbeing and screen time and physical activity.

Findings

Our sample included 577 475 adolescents (mean age 13·60 years, SD 1·64), with 296 542 (51·35%) girls and 280 933 (48·64%) boys. The mean reported life satisfaction score (on a scale of 0–10) was 7·70 (95% CI 7·69–7·71) in boys and 7·48 (7·46–7·50) in girls. Psychosomatic complaints were more common among girls (mean 9·26, 95% CI 9·23–9·28) than boys (6·89, 6·87–6·91). Generalised additive model analyses showed slightly non-linear associations of screen time and physical activity with life satisfaction and psychosomatic complaints for girls and boys. Detrimental associations between screen time and mental wellbeing started when screen time exceeded 1 h per day, whereas increases in physical activity levels were beneficially and monotonically associated with wellbeing. Multilevel modelling showed that screen time levels were negatively associated with life satisfaction and positively associated with psychosomatic complaints in a dose-dependent manner. Physical activity levels were positively associated with life satisfaction and negatively associated with psychosomatic complaints in a dose-dependent manner. Joint associations of screen time–physical activity with mental wellbeing showed that, compared with the least active participants with more than 8 h per day of screen time and no physical activity, most of the other screen time–physical activity groups had considerably higher life satisfaction and lower psychosomatic complaints.

Interpretation

Higher levels of screen time and lower levels of physical activity were associated with lower life satisfaction and higher psychosomatic complaints among adolescents from high-income countries. Public health strategies to promote adolescents' mental wellbeing should aim to decrease screen time and increase physical activity simultaneously.

Funding

None.

中文翻译：

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青少年屏幕时间、身体活动和心理健康之间的剂量依赖性和联合关联：一项国际观察性研究

背景

在过去的几十年中，青少年的心理健康状况大幅下降，因此确定可改变的风险因素很重要。长时间的屏幕时间和身体活动不足似乎会独立和协同作用，增加学龄儿童心理健康不良的风险。我们旨在检查屏幕时间和身体活动与青少年心理健康的性别分层剂量依赖性和联合关联。

方法

我们使用了来自 42 个欧洲和北美国家的三轮学龄儿童健康行为横断面调查（2006 年、2010 年和 2014 年）的数据。年龄分别为 11 岁、13 岁和 15 岁的调查参与者通过填写匿名问卷提供了自我报告的信息，其中包括健康指标和相关行为的项目。我们使用自我报告的生活满意度和心身投诉变量作为青少年心理健康的指标，将这些与自我报告的屏幕使用和身体活动参与相结合。我们使用广义加性模型和多级回归模型来检查心理健康与屏幕时间和身体活动之间的性别分层关系。

发现

我们的样本包括 577 475 名青少年（平均年龄 13·60 岁，SD 1·64），其中 296 542 名（51·35%）女孩和 280 933 名（48·64%）男孩。报告的平均生活满意度得分（0-10 分）为男孩 7·70（95% CI 7·69-7·71），女孩为 7·48（7·46-7·50）。心身不适在女孩（平均 9·26，95% CI 9·23-9·28）中比男孩（6·89，6·87-6·91）更常见。广义加性模型分析显示，女孩和男孩的屏幕时间和身体活动与生活满意度和身心不适之间存在轻微的非线性关联。当每天的屏幕时间超过 1 小时时，屏幕时间与心理健康之间的不利关联就开始了，而身体活动水平的增加与健康有益且单调地相关。多层次模型表明，屏幕时间水平与生活满意度呈负相关，与心身疾病呈正相关，呈剂量依赖性。身体活动水平与生活满意度呈正相关，与心身主诉呈负相关，呈剂量依赖性。屏幕时间-身体活动与心理健康的联合关联表明，与每天屏幕时间超过 8 小时且没有身体活动的最不活跃的参与者相比，大多数其他屏幕时间-身体活动组的生活满意度要高得多和较低的心身投诉。身体活动水平与生活满意度呈正相关，与心身主诉呈负相关，呈剂量依赖性。屏幕时间-身体活动与心理健康的联合关联表明，与每天屏幕时间超过 8 小时且没有身体活动的最不活跃的参与者相比，大多数其他屏幕时间-身体活动组的生活满意度要高得多和较低的心身投诉。身体活动水平与生活满意度呈正相关，与心身主诉呈负相关，呈剂量依赖性。屏幕时间-身体活动与心理健康的联合关联表明，与每天屏幕时间超过 8 小时且没有身体活动的最不活跃的参与者相比，大多数其他屏幕时间-身体活动组的生活满意度要高得多和较低的心身投诉。

解释

在高收入国家的青少年中，较高水平的屏幕时间和较低水平的身体活动与较低的生活满意度和较高的心身抱怨有关。促进青少年心理健康的公共卫生战略应旨在减少屏幕时间并同时增加体育锻炼。

资金

没有任何。