We assessed whether school uniforms are associated with population-level gender inequalities in physical activity, and whether associations differ by school level, country/region income, and assessment method. An ecological study design was employed. We collected data about global uniform practices using an online survey. We searched for country/region-level estimates of school-aged youth meeting physical activity guidelines from international surveillance studies. Study selection was conducted in duplicate using a systematic process, and a random sample of all data was checked to ensure extraction and pooling processes were accurate. We calculated absolute and relative gender inequalities in physical activity for each country. Linear regression examined associations between country/region-level uniform practices (binary yes/no exposure variable) and country/region-level gender inequalities in physical activity guideline compliance (absolute and relative inequalities). We investigated moderation by school level, stratified analyses by income group, and repeated primary analyses using device-measured data. Pooling data from 135 countries/regions ( = 1,089,852), we found no association between population-level uniform practices and gender inequalities in physical activity across all ages (absolute: = –0.2; 95% confidence interval (95%CI): –1.7 to 1.3, = 0.74; relative: = 0.1; 95%CI: –0.1 to 0.2, = 0.51). Subgroup analysis suggested a positive association in primary school settings (absolute: = 4.3; 95%CI: –0.0 to 8.6, = 0.05). Among high-income countries, absolute inequalities were significantly greater in countries/regions with uniform practices ( = 37) compared to those without ( = 48) (9.1 (SD = 3.6) 7.8 percentage points (SD = 4.3)). Repeating analyses using device-measured data ( = 32,130; = 24) did not alter our primary finding. From initial descriptive statistics, we found that in countries/regions where a majority of schools (>50%) reportedly use uniforms, there was lower compliance with physical activity guidelines among all genders (median: 16.0%, interquartile range: 13.2–19.9, = 103) compared to generally non-uniform countries/regions (median: 19.5%, interquartile range: 16.4–23.5, = 32) ( = 3.04, = 0.002). ( = countries, regions and studies represented; = sample size or participants included). School uniforms are associated with greater gender inequalities in physical activity in primary school settings and in high-income countries. Our population-level findings warrant testing using individual-level data across contexts.

中文翻译：

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校服与体育活动中的性别不平等有关吗？对 135 个国家/地区人口数据的汇总分析

我们评估了校服是否与人口层面的身体活动性别不平等有关，以及这种关联是否因学校级别、国家/地区收入和评估方法而异。采用了生态研究设计。我们通过在线调查收集了有关全球统一做法的数据。我们从国际监测研究中检索了符合身体活动指南的学龄青少年的国家/地区水平估计值。使用系统过程重复进行研究选择，并检查所有数据的随机样本，以确保提取和合并过程的准确性。我们计算了每个国家体育活动方面的绝对和相对性别不平等。线性回归检查了国家/地区级统一做法（二元是/否暴露变量）与国家/地区级体力活动指南合规性性别不平等（绝对和相对不平等）之间的关联。我们调查了按学校级别进行的调节、按收入群体进行的分层分析，并使用设备测量数据进行了重复初步分析。汇集来自 135 个国家/地区 (= 1,089,852) 的数据，我们发现人口层面的统一做法与所有年龄段身体活动中的性别不平等之间没有关联（绝对值：= –0.2；95% 置信区间 (95%CI)：–1.7至 1.3，= 0.74；相对：= 0.1；95%CI：–0.1 至 0.2，= 0.51）。亚组分析表明小学环境中存在正相关（绝对值：= 4.3；95% CI：–0.0 至 8.6，= 0.05）。在高收入国家中，采用统一做法的国家/地区 (= 37) 的绝对不平等程度显着高于未采用统一做法的国家/地区 (= 48) (9.1 (SD = 3.6) 7.8 个百分点 (SD = 4.3))。使用设备测量数据（= 32,130；= 24）重复分析并没有改变我们的主要发现。从最初的描述性统计数据来看，我们发现，在据报道大多数学校（>50%）使用校服的国家/地区，所有性别对体育活动指南的遵守程度较低（中位数：16.0%，四分位数间距：13.2-19.9， = 103）与一般不统一的国家/地区（中位数：19.5%，四分位数间距：16.4–23.5，= 32）相比（= 3.04，= 0.002）。 （= 代表的国家、地区和研究；= 样本量或包括的参与者）。在小学和高收入国家，校服与体育活动方面更大的性别不平等有关。我们的人口水平研究结果需要使用跨环境的个人水平数据进行测试。