Hovell Melbourne F, Nichols Jeanne F, Irvin Veronica L, Schmitz Katharine E, Rock Cheryl L, Hofstetter C Richard, Keating Kristen, Stark Lori J
Center for Behavioral Epidemiology and Community Health, Graduate School of Public Health, San Diego State University, San Diego, California 92123, USA.
Am J Health Promot. 2009 Nov-Dec;24(2):118-28. doi: 10.4278/ajhp.08021111.
To test effects of parent/child training designed to increase calcium intake, bone-loading physical activity (PA), and bone density.
Two-group randomized controlled trial.
Family-based intervention delivered at research center.
117 healthy children aged 10-13 years (58.1% female, 42.7% Hispanic, 40.2% White). Ninety-seven percent of participants had at least one parent graduate from high school and 37.2 % had at least one parent graduate from a 4-year university.
Children and parents were randomly assigned to diet and exercise (experimental) or injury prevention (control) interventions. Children were taught in eight weekly classes how to engage in bone-loading PA and eat calcium-rich foods or avoid injuries. Parents were taught behavior management techniques to modify children's behaviors.
Measures at baseline and at 3, 9, and 12 months included 24-hour diet and PA recalls, and bone mineral density (BMD) by dual-energy x-ray absorptiometry.
Analysis of variance and generalized estimating equations (GEE) assessed group by time differences. Comparisons were conducted separately for boys and girls.
For boys, cross-sectional differences between experimental and control groups were achieved for 3- and 9-month calcium intake (1352 vs. 1052 mg/day, 1298 vs. 970 mg/day, p < .05). For girls, marginal cross-sectional differences were achieved for high-impact PA at 12 months (p < .10). For calcium intake, a significant group by time interaction was observed from pretest to posttest for the full sample (p = .008) and for girls (p = .006) but not for boys. No significant group by time differences in calcium were observed across the follow-up period. No group by time differences were observed for high-impact PA. Among boys, longitudinal group by time differences reached significance for total hip BMD (p = .045) and femoral neck BMD (p = .033), even after adjusting for skeletal growth. Similar differential increases were observed among boys for bone mineral content (BMC) at the hip (p = .068) and total body (p = .054) regions. No significant group by time interaction effects were observed for girls at any bone site for BMD. For BMC, control girls showed a significant increase (p = .03) in spine BMC compared to intervention girls.
This study demonstrated that parent/preteen training can increase calcium intake and attenuate the decline in high-impact PA. Results suggest that more powerful interventions are needed to increase activity levels and maximize bone mineral accrual during preadolescent years.
测试旨在增加钙摄入量、骨负荷体力活动（PA）和骨密度的亲子训练效果。
两组随机对照试验。
在研究中心进行基于家庭的干预。
117名10 - 13岁的健康儿童（58.1%为女性，42.7%为西班牙裔，40.2%为白人）。97%的参与者至少有一位家长高中毕业，37.2%的参与者至少有一位家长从四年制大学毕业。
儿童和家长被随机分配到饮食与运动（实验组）或预防损伤（对照组）干预组。通过每周八节课教导儿童如何进行骨负荷PA以及食用富含钙的食物或避免受伤。教导家长行为管理技巧以改变儿童行为。
基线以及3个月、9个月和12个月时的测量指标包括24小时饮食和PA回顾，以及通过双能X线吸收法测量的骨矿物质密度（BMD）。
方差分析和广义估计方程（GEE）评估组间随时间的差异。分别对男孩和女孩进行比较。
对于男孩，实验组和对照组在3个月和9个月时的钙摄入量存在横断面差异（分别为1352 vs. 1052毫克/天，1298 vs. 970毫克/天，p < 0.05）。对于女孩，在12个月时高冲击PA存在边缘性横断面差异（p < 0.10）。对于钙摄入量，全样本从预测试到后测试观察到显著的组间随时间交互作用（p = 0.008），女孩中也观察到该作用（p = 0.006），但男孩中未观察到。在随访期间未观察到钙的显著组间随时间差异。高冲击PA未观察到组间随时间差异。在男孩中，即使在调整骨骼生长后，组间随时间差异在全髋BMD（p = 0.045）和股骨颈BMD（p = 0.033）方面达到显著。在男孩的髋部（p = 0.068）和全身（p = 0.05）区域的骨矿物质含量（BMC）也观察到类似的差异增加。在任何骨部位，女孩的BMD均未观察到显著的组间随时间交互作用。对于BMC，与干预组女孩相比，对照组女孩的脊柱BMC有显著增加（p = 0.03）。
本研究表明亲子/青少年前期训练可增加钙摄入量并减缓高冲击PA的下降。结果表明需要更有效的干预措施来提高活动水平并在青春期前使骨矿物质积累最大化。
