IMPACT OF PHYSICAL ACTIVITY CORRELATES IN THE ISOLATED AND COMBINED PRESENCE OF INSUFFICIENT LEVEL OF PHYSICAL ACTIVITY AND HIGH SCREEN TIME AMONG ADOLESCENTS

ABSTRACT Objective: To identify the impact of physical activity correlates with the isolated and combined presence of insufficient physical activity and high screen time among adolescents. Methods: A cross-sectional representative study was carried out with a sample of 786 adolescents (16.0±1.0 years; 53.9% girls) randomly selected in the schools of São José dos Pinhais, Paraná, Southern Brazil. The physical activity correlates analyzed were sex, nutritional status, economic class and sexual maturation. Physical activity level and screen time were measured and classified according to reference criteria. The associations were tested with Poisson regression and the population attributable fraction (PAF) verified the impact of correlates on the combined presence of insufficient level of physical activity and high screen time by the prevalence ratio (PR). Results: Among the studied adolescents, 84.7% (n=666) were considered insufficiently active, 96.4% (n=758) reported high screen time and 82.1% (n=645) presented the combined presence of these behaviors. The female sex and the high economic status were positively associated with the insufficient level of physical activity (PR=1.19; 95% confidence interval - 95%CI 1.12-1.27; PAF=15.97 - female/adjusted; PR=1,1; 95%CI 1,01-1,19; PAF=9,09 - high/adjusted class). The female sex also was positively associated to high screen time after adjustments (PR=1.18; 95%CI 1.10-1.27; PAF=15.25). The female sex was positively associated with the combined presence of these behaviors (PR=1.18; 95%CI 1.10-1.27) with a 15.25% impact on these behaviors. Conclusions: Physical activity correlates can have an impact on the insufficient level of physical activity and high screen time, especially among girls.

摘要
研究目的：明确身体活动相关影响因素与青少年单独或同时存在身体活动不足及屏幕使用时长过长的关联。
研究方法：本研究于巴西南部巴拉那州圣若泽杜斯平哈伊斯的学校中，随机招募786名青少年（年龄16.0±1.0岁，女生占比53.9%）开展代表性横断面研究。本研究分析的身体活动相关影响因素包括性别、营养状况、社会经济阶层及性成熟状态。依据参考标准对受试者的身体活动水平与屏幕使用时长进行测量并分类。采用泊松回归（Poisson regression）检验变量间的关联，并通过人群归因分值（population attributable fraction, PAF）结合患病率比（prevalence ratio, PR），分析相关影响因素对青少年同时存在身体活动不足与屏幕使用时长过长的影响强度。
研究结果：本研究纳入的青少年中，84.7%（n=666）存在身体活动不足，96.4%（n=758）屏幕使用时长过长，82.1%（n=645）同时存在上述两种行为。女性性别与较高社会经济阶层与身体活动不足呈正相关（校正后患病率比PR=1.19，95%置信区间（confidence interval, CI）1.12~1.27；女性的人群归因分值PAF=15.97；校正后较高社会经济阶层PR=1.1，95%CI 1.01~1.19，PAF=9.09）。校正后分析显示，女性性别同样与屏幕使用时长过长呈正相关（PR=1.18，95%CI 1.10~1.27，PAF=15.25）。女性性别与两种行为同时存在呈正相关（PR=1.18，95%CI 1.10~1.27），对该合并行为的人群归因分值为15.25%。
研究结论：身体活动相关影响因素可对青少年身体活动不足及屏幕使用时长过长产生显著影响，尤其在女性群体中更为突出。