OSTEOPOROSIS PREVENTION IN PREADOLESCENT GIRLS (BE A STAR! BANK ON YOUR BONES!)

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We have developed an innovate behavioral/education intervention designed to decrease modifiable risk factors for osteoporosis in preadolescent girls. The objective of the proposed study is to demonstrate the efficacy of this intervention in increasing levels of dietary calcium intake and weight-bearing exercise within an at-risk population in a stage of rapid accrual of bone mass--specifically, premenarchal Girl Scouts between the ages of 10 and 12. Cluster randomization will be used to randomize Girl Scout troops to either the intervention or a program of education only. Eighteen Girl Scout troops (144 girls) will be randomized into each arm (i.e., an estimated 8 girls participating per troop). The intervention consists of 3 interactive sessions utilizing various media (i.e., overhead transparencies, graphics, and three-dimensional demonstrations) to present instructional material. Topics include an explanation of osteoporosis and its modifiable and non-modifiable risk factors, prevention of osteoporosis via healthy food choice (i.e., high calcium, low fat foods), and prevention of osteoporosis via weight-bearing exercise (specifically, jumping rope.) Each girl is given a "3-day Star Chart" with colorful graphics for easy self-monitoring of her progress toward the goal of 1350 to 100 mg of calcium per day. Star stickers represent serving sizes of foods that contain either 150 mg (1 star) or 300 mg (2 stars) of calcium. The "Star Exercise Pyramid" similarly allows simple self monitoring of weight-bearing activity to be recorded with stars representing 5-, 10- or 15-minutes blocks of weight bearing exercise per week. Incentives are given to the girls to reinforce the content of the intervention sessions-- i.e., a food pyramid magnet, a mug with markings for 1 and 2 cup serving sizes, jump ropes, a booklet of jump rope games. The intervention program is reinforced via monthly self monitoring for 18 months. The education only program consists of three generic sessions on healthy eating, physical fitness, and healthy lifestyle choices. The primary outcomes of interest are higher calcium intake and higher levels of weight bearing exercise. A secondary outcome of interest is increased broadband ultrasound attenuation of the os calcis assessed using quantitative ultrasound. In summary, the group of girls targeted is ideal for this intervention since they are at a stage of rapid accrual of bone mass. We postulate that the intervention will maximize their opportunity for attaining potential peak bone mass, thus serving to further the ultimate goal of osteoporosis prevention.