E-14C Free Communication/Slide Gender Related Strength and Conditioning
Bone mass accrual during childhood is a determinant of peak bone mass in adults.
to compare bone mineral density/bone mineral content (BMD/BMC, by DXA) and lifestyle factors known to affect bone health among Caucasian (N=42), Hispanic (N=38) and African-American (N=16) children aged 10–13 (11.4 ± 1.1 yr, mean ± SD).
Baseline data from a randomized trial to determine intervention effects of increased dietary calcium and physical activity were examined by ANCOVA, with age and body weight as covariates in all analyses.
In girls (N=61), total body BMD and BMC were significantly greater in African-Americans (1.055 ± 0.100 g.cm-2, p < .01; 1936 ± 546 g, p < .02), compared to Caucasians (0.984 ± 0.094 g.cm-2; 1736 ± 458 g) and Hispanics (0.989 ± 0.099 g.cm-2; 1805 ± 462 g). BMC of the spine (L1-L4) was also greater in African-American girls (38.4 ± 14.7 g) compared to Caucasian (33.5 ± 10.8 g) and Hispanic girls (31.7 ± 12.7 g, p < .05). No ethnic differences in BMD or BMC were found in boys (N=35). Total physical activity, determined by interviewer-administered questionnaire, was similar among the 3 ethnic groups, as was dietary calcium determined by mean of 3, 24-hr dietary recalls. Likewise, lower body strength (sum of 1 RMs), vertical jump scores and aerobic power (VO2max) in girls and boys were not significantly different by ethnicity. However, boys had significantly higher scores for vertical jump (31.8 ± 6.3 vs 28.8 ± 6.0 cm, p < .006) and aerobic power (43.6 ± 9.4 vs. 35.4 ± 5.4 ml.kg-1.min−1, p < .0001) and consumed more calcium (1223 ± 708 vs 997 ± 408 mg/d, p < .037) than girls.
These data indicate that lifestyle factors known to influence bone mass in children did not differ among this sample of African-American, Caucasian and Hispanic children, although, BMD/BMC was greater in African-Americans compared to Caucasian and Hispanic girls. Calcium intake by both boys and girls was below that recommended for children, while total physical activity exceeded recommendations. Supported by NIH-NCHHD: RO1 HD37749