Usefulness of the Bone Loading History Questionnaire in Children

Abstract

Lifetime physical activity (PA) is an important determinant of bone health and has been evaluated in adults by means of the Bone Loading History Questionnaire (BLHQ). PURPOSE: To analyze the association between BLHQ scores and bone mineral and size in 8 and 9 year old boys and girls. METHODS: Participants were 110 healthy and normally active children, 48 girls (8.5±0.4 yrs) and 62 boys (8.6±0.4 yrs). Measurements of body weight, lean body mass (LM), bone mineral content (BMC), and bone area (BA) of the lower limbs, femoral neck, and lumbar spine, were made by DXA, and skeletal age was determined by Tanner-Whitehouse III method. Lifetime bone loading exposure was calculated for both the lower limbs/hip and the spine using the BLHQ, taking into account the type of activity, the rate of force applied to these skeletal sites, and the frequency of exposure in PAs realized regularly, according to Dolan et al. (2006). Current PA was assessed with accelerometry over 7 days. RESULTS: Comparisons by t-test revealed that boys had higher values than girls for BMC and area of lower limbs (353±109 vs. 309±88 g, p=0.026; and 396±87 vs. 362±73 cm2, p=0.033), and lumbar spine (18.0±3.1 vs. 16.7±3.0 g, p=0.034; and 27.3±3.2 vs. 25.6±2.5 cm2, p=0.003), and for femoral neck BMC (3.3±0.6 vs. 2.9±0.3 g, p<0.001). Boys had higher values than girls for BMI (17.9±2.9 vs. 16.6±2.3 kg/m2, p=0.017), and for LM (22.8±3.1 vs. 20.3±2.5 kg, p<0.001). Boys were also more active than girls (695±142 vs. 575±157 counts/d, p<0.001; and 87±27 vs. 61±25 min/d of moderate plus vigorous PA, p<0.001), but had similar total bone loading exposure for lower limbs/hip or spine. After controlling for bone age, body weight, and body height, significant correlations between total bone loading exposure of the lower limbs/hip and BMC and BA of lower limbs were found in girls (r=0.375-0.399, p<0.05) and between moderate plus vigorous PA and BMC and BA of femoral neck in boys (r=0.280-0.337, p<0.05). CONCLUSIONS: The BLHQ appears to be useful to quantify components of PA which are important to bone health when PA is determined mainly by organized activities or movements; this appears to be true for girls but not for boys, at least until 8-9 years, because boys present a high level of spontaneous PA. Funded by Portuguese Science and Technology Foundation and POCI 2010, POCTI/DES/58762/2004.