TY  - JOUR
TI  - YOUTH: a health plan--based lifestyle intervention increases bone mineral density in adolescent girls
AU  - DeBar, L.
AU  - Ritenbaugh, C.l.
AU  - Aickin, M.
AU  - Orwoll, E.
AU  - Elliot, D.
AU  - Dickerson, J.
AU  - Vuckovic, N.
AU  - Stevens, V.
AU  - Moe, E.
AU  - Irving, L.
AB  - Objective  To test the efficacy of a health plan–based lifestyle intervention to increase bone mineral density in adolescent girls.  Design  Two-year randomized, controlled trial.  Setting  Large health maintenance organization.  Participants  Girls 14 to 16 years old with body mass index below the national median.  Intervention  Behavioral intervention (bimonthly group meetings, quarterly coaching telephone calls, and weekly self-monitoring) designed to improve diet and increase physical activity.  Main Outcome Measures  Total bone mineral density was measured by dual-energy x-ray absorptiometry. Behavioral outcomes included intake of calcium, vitamin D, soda, and fruits and vegetables; high-impact and strength-training physical activity; measures of strength and fitness; and biomarkers (osteocalcin and naltrexone).  Results  Compared with control subjects, girls in the intervention group had significantly higher bone mineral density in the spine and trochanter regions during the first study year, which was maintained during the second study year. The naltrexone biomarker demonstrated a greater relative decrease in the intervention group compared with the control group, with nonsignificant changes in osteocalcin consistent with more bone building in the intervention group. Participants in the intervention group reported significantly greater consumption of calcium in both study years, vitamin D in the first year, and fruits and vegetables in both years. We found no effect on soda consumption or target exercise rates.  Conclusions  A comprehensive health care–based lifestyle intervention can effectively improve dietary intake and increase bone mineral gains in adolescent girls. To our knowledge, this study is the first to significantly improve bone mass in adolescent girls in a non–school-based intervention.  Trial Registration  ClinicalTrials.gov Identifier: NCT00067600.  The primary prevention of osteoporosis is an important public health target. Almost half of all women in the United States older than 50 years demonstrate low bone density (osteopenia).1 An estimated 1.3 million osteoporosis-related fractures occur each year in the United States, with annual costs of approximately $13.8 billion.2 One determinant of lifetime osteopenia and osteoporosis risk is low bone mineral density (BMD). Because 90% of peak bone mass is acquired by age 18 years,3- 5 interventions to maximize BMD in youth may decrease the incidence of osteopenia later in life. For this reason, the National Institute of Child Health and Health Development recently requested applications (RFA: HD-97-006) for the prevention of adult osteoporosis by targeting BMD in youth.  Although a substantial component of osteoporosis risk is genetic,6,7 both diet and physical activity are important modifiers of bone accrual.3 Several controlled trials have found that increasing calcium intake increases BMD in youth.8- 10 Other dietary factors also may maximize the retention of calcium in bones, but few randomized trials have examined these factors in adolescents. Studies suggest that greater fruit and vegetable intake is important for bone health11,12 and is associated with higher BMD.13,14 In addition, studies15,16 suggest that achievement of peak bone mass in adolescent girls is contingent on adequate vitamin D intake. Further, consuming caffeinated beverages, particularly colas, increases risk of bone fracture.17,18 Finally, many studies have suggested that increasing weight-bearing activity increases BMD in children and adolescents.19- 24  Although much of the research on building healthy bones in youth has targeted younger children,19,21,23,25,26 adolescents may be an equally important target population. Eating and exercise patterns established in adolescence may be more likely to be sustained into adulthood than similar efforts aimed at younger children.27,28 Gains in bone mass are most rapid during adolescence, with as much as 51% of peak bone mass accumulated during pubertal growth.29,30 Interventions to prevent osteoporosis are particularly important in adolescent girls, because they are at a higher risk of developing osteoporosis in adulthood than males.31 Recent reports suggest that vigorous exercise declines in adolescents,32 which makes this time key for intervention.  Preventive interventions conducted in youth generally have involved calcium supplementation, controlled feeding trials, or prescribed exercise in a controlled setting; that is, they have not emphasized sustainable behavioral practices and, thus, not represented community trials. Further, existing youth interventions are mainly school based,33- 36 largely overlooking the opportunities in other settings such as health care. Inasmuch as most children and adolescents (about 80%) visit a medical provider at least annually (76 million annual contacts with physicians37), such visits are a largely untapped setting in which to offer primary prevention programs. Pediatric patients are influenced by physician advice and are receptive to health behavior recommendations.38 Thus, adolescents may comply with targeted lifestyle interventions offered through health care settings more than with those offered in schools.
IS  - 12
JO  - Archives of pediatrics \& adolescent medicine
PY  - 2006
SP  - 1269
UR  - archpedi.jamanetwork.com/article.aspx?articleid=205842
VL  - 160
LA  - English
ER  -