Factors associated with low levels of aerobic fitness among adolescents

Abstract Objective: To evaluate the prevalence of low aerobic fitness levels and to analyze the association with sociodemographic factors, lifestyle and excess body fatness among adolescents of southern Brazil. Methods: The study included 879 adolescents aged 14-19 years the city of São José/SC, Brazil. The aerobic fitness was assessed by Canadian modified test of aerobic fitness. Sociodemographic variables (skin color, age, sex, study turn, economic level), sexual maturation and lifestyle (eating habits, screen time, physical activity, consumption of alcohol and tobacco) were assessed by a self-administered questionnaire. Excess body fatness was evaluated by sum of skinfolds triceps and subscapular. We used logistic regression to estimate odds ratios and 95% confidence intervals. Results: Prevalence of low aerobic fitness level was 87.5%. The girls who spent two hours or more in front screen, consumed less than one glass of milk by day, did not smoke and had an excess of body fatness had a higher chance of having lower levels of aerobic fitness. White boys with low physical activity had had a higher chance of having lower levels of aerobic fitness. Conclusions: Eight out of ten adolescents were with low fitness levels aerobic. Modifiable lifestyle factors were associated with low levels of aerobic fitness. Interventions that emphasize behavior change are needed.

摘要
研究目的：评估巴西南部青少年有氧适能（aerobic fitness）低下的患病率，并分析其与社会人口学因素、生活方式及体脂过剩的关联。
研究方法：本研究纳入巴西圣卡塔琳娜州圣若泽市879名14~19岁的青少年。有氧适能采用加拿大改良有氧适能测试进行评估。社会人口学变量（肤色、年龄、性别、学习时段、经济水平）、性成熟状态及生活方式（饮食习惯、屏幕暴露时长、体力活动、烟酒摄入情况）通过自填式问卷完成采集。体脂过剩通过肱三头肌与肩胛下皮褶厚度之和进行评估。本研究采用logistic回归计算比值比（odds ratio, OR）及95%置信区间（95% confidence interval, 95%CI）。
研究结果：青少年有氧适能低下的患病率为87.5%。每日屏幕暴露时长≥2小时、每日牛奶摄入量不足1杯、无吸烟史且存在体脂过剩的女性，其有氧适能低下的风险更高；体力活动水平低下的白人男性，有氧适能低下的风险亦显著升高。
研究结论：每10名青少年中即有8名存在有氧适能低下的情况，可干预的生活方式因素与有氧适能低下存在明确关联，亟需出台强调行为改变的针对性干预措施。