Cradock Angie L, Melly Steven J, Allen Joseph G, Morris Jeffrey S, Gortmaker Steven L
Department of Society, Human Development and Health, Harvard School of Public Health, Boston, Massachusetts 02115, USA.
J Adolesc Health. 2009 Sep;45(3 Suppl):S91-8. doi: 10.1016/j.jadohealth.2009.06.007.
Limited availability of desirable destinations within walkable distances and unsuitable weather may adversely affect physical activity among adolescents on weekends. This study examines evidence for associations between objective measures of local environment and physical activity levels of adolescents.
Students (n=152, 59% male; mean age, 13.7 years) from 10 neighborhoods with schools in four communities wore TriTrac-R3D accelerometers recording physical movements on weekends. Minute-by-minute data were summed over 15-minute intervals providing estimates of proportion of time spent in moderate and vigorous physical activity (MVPA) and (log) mean physical activity levels on weekends (n=7,506 intervals). Objective measures of neighborhood characteristics were calculated using geographic information systems including average daily traffic, housing density, open space, and density of employees per square kilometer in youth destinations. Linear mixed models were fit examining associations between neighborhood environmental variables and accelerometer measures of physical activity, controlling for time, day, age, body mass index, gender of respondent, race/ethnicity, precipitation, and temperature deviation.
On weekends, the presence of greater densities of employees in neighborhood destinations serving youth (beta=3.96, p=0.050) was directly associated with MVPA, independent of student characteristics.
Young people attending schools in neighborhoods characterized by greater densities of employees in destinations for youth are more physically active on weekends. Compared with neighborhoods with lower densities, attending a school in neighborhoods with higher densities of employees in potential destinations for youth may contribute to participation in an additional 30 minutes of MVPA per day on weekends.
适宜步行到达的理想目的地数量有限以及天气不适宜可能会对青少年周末的身体活动产生不利影响。本研究检验了当地环境客观指标与青少年身体活动水平之间关联的证据。
来自四个社区中十所设有学校的街区的学生(n = 152,男性占59%;平均年龄13.7岁)佩戴TriTrac - R3D加速度计记录周末的身体活动情况。逐分钟数据按15分钟间隔进行汇总,以估算周末中度至剧烈身体活动(MVPA)的时间比例以及(对数)平均身体活动水平(n = 7506个间隔)。使用地理信息系统计算街区特征的客观指标,包括日均交通流量、住房密度、开放空间以及青少年目的地每平方公里的员工密度。采用线性混合模型检验街区环境变量与身体活动加速度计测量值之间的关联,并控制时间、日期、年龄、体重指数、受访者性别、种族/族裔、降水量和温度偏差。
在周末,为青少年服务的街区目的地中员工密度较高(β = 3.96,p = 0.050)与MVPA直接相关,且独立于学生特征。
在以青少年目的地员工密度较高为特征的街区上学的年轻人在周末身体活动更积极。与员工密度较低的街区相比,在潜在青少年目的地员工密度较高的街区上学可能有助于在周末每天增加30分钟的MVPA参与时间。