Chavarro Jorge E, Peterson Karen E, Sobol Arthur M, Wiecha Jean L, Gortmaker Steven L
Department of Nutrition, Harvard School of Public Health, 665 Huntington Ave., Boston, MA 02115, USA.
Cancer Causes Control. 2005 Dec;16(10):1245-52. doi: 10.1007/s10552-005-0404-5.
Early menarche is a risk factor for breast cancer. Since body composition influences age at menarche we decided to estimate the effects of a school-based intervention for the prevention of obesity on the initiation of menses in young girls.
Ten schools were randomized to a modified curriculum or no curricular changes for 2 school-years. Data of 508 pre-menarcheal girls at baseline (age range: 10-13 years) were analyzed.
Girls attending an intervention school experienced menarche less frequently than girls attending control schools during the intervention period (intervention schools = 54%, control schools = 59%; RR = 0.76; 95% CI [0.66, 0.87]). Attending an intervention school was also associated with lower increase in BMI (-0.3 kg/m2; p = 0.003), lower gains in triceps skinfold thickness (-1.5 mm; p = 0.007), decreased television viewing (-0.6 h/day; p<0.0001) and increased physical activity (3.1 MET-h/week; p = 0.032). Including these changes as predictors of menarche incidence attenuated the intervention effect (RR = 0.94; 95% CI [0.80, 1.10]).
The intervention delayed menarche in this group of girls. The delay was produced by increased physical activity, reduced television viewing and changes in BMI and fat distribution. These findings may have implications for the primary prevention of breast cancer.
初潮过早是乳腺癌的一个风险因素。由于身体组成会影响初潮年龄，我们决定评估一项以学校为基础的预防肥胖干预措施对年轻女孩月经初潮的影响。
10所学校被随机分为接受改良课程组或在两个学年内不改变课程组。对508名基线时处于月经初潮前的女孩（年龄范围：10 - 13岁）的数据进行了分析。
在干预期间，就读于干预学校的女孩月经初潮的频率低于就读于对照学校的女孩（干预学校 = 54%，对照学校 = 59%；相对危险度 = 0.76；95%置信区间[0.66, 0.87]）。就读于干预学校还与较低的体重指数增加（-0.3kg/m²；p = 0.003）、肱三头肌皮褶厚度增加较少（-1.5mm；p = 0.007）、看电视时间减少（-0.6小时/天；p<0.0001）以及身体活动增加（3.1代谢当量小时/周；p = 0.032）相关。将这些变化作为月经初潮发生率的预测因素纳入分析后，干预效果减弱（相对危险度 = 0.94；95%置信区间[0.80, 1.10]）。
该干预措施延迟了这组女孩的月经初潮。这种延迟是由身体活动增加、看电视时间减少以及体重指数和脂肪分布的变化导致的。这些发现可能对乳腺癌的一级预防具有启示意义。
