The use of quantitative ultrasound (QUS) of the bone is rapidly gaining in popularity, and QUS is widely used worldwide for the assessment of skeletal status. Although much has been learned about the influence of various factors on ultrasonic parameters in various populations, similar information at the local level is not available. This study was carried out to examine the effects of anthropometric, dietary, physical activity, reproductive, and other lifestyle factors on QUS parameters in healthy Greek women, including children (n=217), adults (n=235), and elderly (n=369) subjects. Calcaneal QUS measurements were performed with the SAHARA device, which measures broadband ultrasound attenuation (BUA) and speed of sound (SOS) through the os calcis; a composite parameter, the quantitative ultrasound index (QUI), and an estimate of heel bone mineral density (eBMD) were also derived. All QUS indices were higher in adult women than in girls or elderly women (P<0.05). The latter had a similar BUA to girls, but lower SOS, QUI, and eBMD (P<0.05). Most QUS parameters correlated positively with height, weight, body mass index (BMI), hip circumference, organized physical activity, and activity promoting bone mass, but negatively with the time devoted to sedentary activities and absolute carbohydrate intake (P<0.05). Age of menarche and years since menopause were negatively associated with QUS in the adult and elderly women, respectively (P<0.05). The latter relationship, however, was due to the confounding effect of advancing age. Overweight and obese females had significantly higher BUA and eBMD than normal-weight subjects (P<0.05), but similar SOS and QUI; this held true for all age groups. Likewise, in all ages, individuals spending more than 2 h/week on organized activities had significantly higher QUS indices than those spending less time on exercise (P<0.05). Further, postmenarchial girls had significantly higher age-adjusted BUA, SOS, QUI, and eBMD than premenarchial ones (P<0.05). Similarly, all QUS parameters were significantly higher in adult women with an early onset of menarche (<14 years old) than in those with a late onset (P<0.05), but no effects of menarche were detected among the elderly. No significant effects of calcium intake (which was generally adequate), smoking or alcohol drinking (which were generally low) on QUS indices were observed, in either age group. Available independent variables could explain approximately 16%-24% of the total variance in BUA, SOS, QUI and eBMD. The most important positive predictors of QUS were adulthood, time devoted to organized activities, and weight or BMI, while age and carbohydrate intake per se contributed negatively. In conclusion, age, body size, physical activity, and some aspects of reproductive history and diet appear to variably affect calcaneal QUS indices among otherwise healthy Greek women at different life stages.

The aim of this study was to develop and evaluate a food frequency questionnaire (FFQ) for assessing dietary calcium intake in the general population, since all available questionnaires at present are age- and/or gender-specific. A total of 1001 individuals (including children, adults, and elderly people of both genders) were randomly recruited throughout Greece. Estimates of calcium intake from the 30-item FFQ were compared with those from a multi-pass 24-h recall. The FFQ underestimated mean calcium intake compared to the 24-h recall by (mean+/-SD) -133+/-333 mg/day or -5.4+/-47.6% (P<0.001). The two methods were strongly correlated (r=0.639, P<0.001), but the 95% limits of agreement for individual assessment were rather wide, as the FFQ could provide estimates of calcium intake from 533 mg/day above to 799 mg/day below the 24-h recall. Actual values for surrogate FFQ quartiles manifested a progressive increase, with significant differences between mean calcium intakes (P<0.001). The FFQ could identify individuals who consumed less calcium than 800 mg/day or less than the age-specific adequate intake with a relatively high sensitivity (82.8 and 95.5%, respectively), but low specificity (54.9 and 34.1%, respectively). Cross-classification analysis indicated that only 17 subjects (1.7%) were grossly misclassified (lowest quartile for one method and highest quartile for the other), while 827 subjects (82.6%) were correctly classified (into the same or adjacent quartiles). The FFQ could be used in population-based epidemiological studies or screening programs involving individuals of all ages and both genders, where the discrimination of subjects with relatively low (<500 mg/day) and relatively high (>1000 mg/day) calcium intakes is of primary interest. Results, however, do not support its use for the quantitative assessment of individual calcium intakes.

Quantitative ultrasound (QUS) is a peripheral bone densitometry technique that is rapidly gaining in popularity for the assessment of skeletal status. This study was carried out to examine the effect of anthropometric, dietary, physical activity, and other lifestyle factors on QUS parameters in healthy Greek males of various ages, including children (n=192), adults (n=106), and elderly (n=86) subjects. Calcaneal QUS measurements were performed with the Sahara device (Hologic), which measures broadband ultrasound attenuation (BUA) and speed of sound (SOS) through the os calcis. A composite parameter, the quantitative ultrasound index (QUI), and an estimate of heel bone mineral density (eBMD) were also derived. BUA correlated positively with height, weight, and body mass index, as well as waist and hip circumferences (P<0.001), but this was not the case for SOS. QUI and eBMD were inconsistently related with anthropometric characteristics. Overweight and obese males had significantly higher BUA than normal-weight subjects (P<0.05), but similar SOS, QUI, and eBMD; this held true for all age groups. Boys participating in organized physical activities had significantly higher SOS, QUI, and eBMD than those who did not (P<0.05), although BUA was similar in the two groups; no differences according to organized physical activity were detected in adults and the elderly. On the other hand, adult men devoting at least some time to non-organized physical activities had significantly higher QUS values than their non-exercising peers (P<0.05); no such effects, however, were seen in children and the elderly. Adult men with calcium intakes above 800 mg/day had significantly higher SOS, QUI, and eBMD than those consuming less calcium (P<0.05), and also tended towards higher BUA (P=0.079); no such differences were observed among children and elderly men. The effects of physical activity and calcium intake on heel QUS persisted even after controlling for body size. Overall, body weight was the sole significant positive determinant of BUA (beta=0.373; t=6.589; P<0.001), explaining approximately 14% of the total variance, while age was the sole significant negative determinant of SOS (beta=-0.198; t=-3.321; P=0.001), albeit explaining only less than 4% of the total variance. In conclusion, body size, dietary calcium intake, and physical activity patterns seem to inconsistently and age-dependently influence heel QUS among healthy Greek males in a parameter-specific manner.

There may be several significant differences in the quantitative and qualitative performance of a calcium-specific FFQ across age and sex. This should be taken into account when attempting to evaluate dietary calcium intake in men and women or in different age groups, as some of the differences between study groups may actually be due to the different response of these groups to the FFQ.

Quantitative ultrasound (QUS) is a peripheral bone densitometry technique that is rapidly gaining in popularity, and is widely used worldwide for the assessment of skeletal status. This, however, generally occurs in the absence of adequate clinical guidelines. As accurate interpretation of the results and correct classification in individual fracture risk assessment are of great value, the present study was carried out to establish a reference database for calcaneal QUS measurements across age group and gender in Greece. A total of 1205 subjects (821 females and 384 males) from three age groups (409 children, 341 adults and 455 elderly) were recruited. QUS measurements were performed at the heel with the Sahara device, which measures broadband ultrasound attenuation (BUA) and speed of sound (SOS), and then combines these variables into a single parameter, the quantitative ultrasound index (QUI). Overall, gender-related differences were more pronounced among the elderly, while age-related differences were more pronounced among females. Elderly men had higher QUS parameters than women of peer age, but no major gender differences were observed in children and adults. In males, only BUA showed a variation with age, being higher in adult and elderly men compared to boys. On the other hand, all QUS parameters varied significantly with age in females, the general trends being mildly positive from childhood to adulthood, when peak levels were observed, and negative thereafter. The results for the Greek population were in the range reported previously for other populations, but some discrepancies were evident, probably resulting from ethno-specific characteristics and different QUS instrumentation. Importantly, using the manufacturer's or the local database as the reference population for computing T-scores led to significantly different classification of subjects into conventional categories of risk. These data could be useful as a guide for comparing the results of individual studies, as well as for the assessment of Greek men and women at risk of fracture.