OBESITY PREV AMONG PREPUBERTAL AFRICAN AMERICAN GIRLS

肥胖是几种成人慢性疾病的危险因素。肥胖在非裔美国人（AA）中比其他种族更普遍，尤其是AA女性。肥胖从童年一直延续到成年。超过50百分位（50% tile）和/或有一个或两个肥胖父母的孩子比其他人更有可能变得肥胖。因此，在青春期前和青春期早期对高危人群进行干预，可能会预防那些尚未肥胖的人肥胖，并预防或减少那些已经超重的人的体重进一步增加，并降低慢性疾病负担。我们假设每天参加60分钟或更长时间的中度到剧烈的体育活动，每天吃5份或更多的水果、果汁和蔬菜（FJ和V），减少饮食中的脂肪摄入量，将使体重指数在50%以上或有一个或多个肥胖父母的青春期前8岁AA女孩在两年的时间里体重增加最小化。行为目标将通过为期两年的干预来实现，包括为期四周的夏令营和为期23个月的亲子每周互动娱乐，食品和健身网站，以了解健康饮食和体育活动。本研究将采用随机两组（治疗-对照）设计，从336名女孩开始，在基线、项目中期（+12个月）、项目后（+24个月）和项目后一年（+36个月）每年进行4次重复测量。主要干预结果将是DEXA测量的体重和脂肪增加；次要结局包括心血管疾病风险因素、双标签水测量的能量消耗、饮食习惯和社会心理变量。候选基因多态性和静息代谢率将被检查与肥胖相关表型和干预反应的关联。在干预之前（第一阶段），我们将启动三项研究：1)测试两种体育活动自我报告方法的有效性（24小时体育活动回忆与一周体育活动回忆）；2)评估影响这些女孩体育活动的家庭和个人因素；3)开发和试点一个对文化敏感的为期一个月的夏令营和两个月的万维网项目，以帮助8yo AA女孩改变她们的饮食和体育活动习惯。这将是第一个使用长达一个月的夏令营、网络技术和复杂的生物测量来评估预测身体成分变化的因素的肥胖预防项目。

Obesity is a risk factor for several adult chronic diseases. Obesity is more prevalent among African-Americans (AA) than other ethnic groups, especially AA females. Obesity tracks from childhood into the adult years. Children above the 50th percentile (50 percent tile) and/or who have one or two obese parents are more likely to become obese than others. Thus, intervening just before and early in puberty among those at high risk may prevent obesity among those not already obese, and prevent or minimize further weight gain among those already overweight and lower chronic disease burden. We hypothesize that participation in 60 min or more per day of moderate to vigorous physical activity, eating 5 or more servings of fruit, juice and vegetables (FJ and V) per day, and decreasing dietary fat intake will minimize weight gain over a two year period among prepubertal 8-year-old (yo) AA girls in the upper 50 percent tile of BMI or who have one or more obese parents. Behavioral objectives will be achieved through a 2-year intervention consisting of a four-week summer day camp and a 23 month child-parent weekly interactive Fun, Food and Fitness web site to learn about healthy eating and physical activity. This study will employ a randomized two group (treatment-control) design with four annual repeated measures at baseline, mid program (+12 mo), post program (+24 mo), and a year after the program(+36 mo) starting with 336 girls. The primary intervention outcomes will be body weight and fat gain as measured by DEXA; secondary outcomes include cardiovascular disease risk factors, energy expenditure measured by doubly labeled water, dietary practices and psychosocial variables. Candidate gene polymorphisms and resting metabolic rate will be examined for association with obesity related phenotypes and response to intervention. Prior to the Intervention (Phase I) we will initiate three studies: 1) test of the validity of two alternative approaches to self-report of physical activity (24-hour physical activity recall vs. week activity recall); 2) assessment of family and personal factors that influence physical activity among these girls; and 3) development and pilot testing of a culturally sensitive month-long summer camp and two month world wide web program to help 8yo AA girls change their dietary and physical activity practices. This will be the first obesity prevention project to employ a month-long summer camp, web technology, and sophisticated biological measures to assess factors predictive of body composition change.