Parent/Child Training to Increase Preteens' Calcium, Physical Activity, and Bone Density: A Controlled Trial

Abstract

PURPOSE To test effects of parent/child training designed to increase calcium intake, bone-loading physical activity (PA), and bone density. DESIGN Two-group randomized controlled trial. SETTING Family-based intervention delivered at research center. SUBJECTS 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. INTERVENTION 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 Measures at baseline, three, nine and twelve months included 24-hour diet and PA recalls, and bone mineral density (BMD) by DXA. ANALYSIS ANOVA and Generalized Estimating Equations assessed group by time differences. Comparisons were conducted separately for boys and girls. RESULTS For boys, cross-sectional differences between experimental versus control group were achieved for 3 and 9-month calcium intake (1352 vs. 1052mg/day, 1298 vs. 970mg/day, p<0.05). For girls, marginal cross-sectional differences were achieved for high-impact PA at 12 months (p<0.10). For calcium intake, a significant group by time interaction was observed from pre to post test 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 physical activity. 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 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 CONCLUSION 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 pre-adolescent years.

Improving children's dairy food and calcium intake: can intervention work? A systematic review of the literature

“…The present review summarises sixteen papers describing fourteen interventions published between years 1990 and 2010, conducted mainly in the USA (30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41) , one in South America (42) and three in Europe (43)(44)(45) . Children's age spanned from 5 to 12 years, and with the exception of one study that recruited girl scouts only (35) , all studies targeted both girls and boys.…”

“…Six interventions targeted both dietary and physical activity behaviours (30,33,35,37,38,45) , the other eight focused solely on dietary behaviour. It was common for interventions to target an increase in dairy foods within the context of a healthy diet (n 9).…”

“…Outcome evaluation focused primarily on short-term effects (end of intervention) with only five articles reporting follow-up effects post-intervention (34,36,37,43,44) . The intervention techniques were delivered in schools (n 4), the community (n 3), the home (n 2) and within research organisations (n 2).…”

“…Resources provided to the participants as part of the intervention were varied. Some studies provided government-published pamphlets about healthy eating and/or access to specialised equipment for physical activity components of the intervention (34,38) , others provided children with milk to be consumed as part of the intervention (31,42,44) or with Ca-rich meals or snacks to be consumed during the intervention sessions (30,35,37) (see Supplementary Materials).…”

“…nutritionist visits (36,42) ) or group contact with an individual component (e.g. group education with individualised goal setting (33,34,37,43) ). Intervention duration of the higher intensity studies was at minimum 12-16 weeks (38,42) , with most intervening for at least 12 months, but some up to 36 months.…”