Development and validation of a food frequency questionnaire for assessing dietary calcium intake in the general population

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.     

Neuropsychological examination detects post-operative complications in idiopathic normal pressure hydrocephalus (iNPH): report of two cases

Subdural fluid collections (SFC) are characteristic complications of shunting for idiopathic normal pressure hydrocephalus (iNPH). This report presents two shunted iNPH patients with clinically silent postoperative SFC, detected after abnormal neuropsychological findings. These cases highlight the value of neuropsychological assessment in the routine postoperative assessment of iNPH.     

Changing relationships of obesity and dyslipidemia in Greek children: 1982-2002

BACKGROUND: The prevalence of childhood overweight and obesity has been increasing rapidly during the past decades in many parts of the world. Less is known with respect to the effects of increasing adiposity on blood lipid profile. The present study was designed to examine the influence of adiposity on secular trends in anthropometric characteristics and plasma lipids of Greek children. METHODS: A total of 419 and 374 boys with normal body weight and 109 and 246 boys with abnormal body weight (overweight and obese) were randomly recruited in 1982 and 2002, respectively (aged 12.1 +/- 0.1 years). Height, weight, body mass index (BMI, kg/m(2)), Rohrer index (kg/m(3)), plasma total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), triglyceride (TG), TC/HDL-C ratio, and LDL-C/HDL-C ratio were determined. RESULTS: Temporal changes in weight (positive), BMI (positive), HDL-C (negative), and cholesterol ratios (positive) were greater among overweight and obese vs. normal-weight boys (P < 0.05), while those for height (positive), LDL-C (positive), TG (positive), and TC (no change) were of similar magnitude. The increase in Rohrer index since 1982 failed to reach significance for children with normal body weight (P = 0.077) but did so for overweight and obese subjects (P = 0.027). CONCLUSIONS: These results indicate that secular increases in measures of fatness and adverse changes in plasma lipids were more pronounced among overweight and obese children than among normal-weight individuals, although qualitatively similar shifts were observed across the entire population.     

Body mass index, calcium intake, and physical activity affect calcaneal ultrasound in healthy Greek males in an age-dependent and parameter-specific manner

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 800mg/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 ( = 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 ( = –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.     

Quantitative ultrasound calcaneus measurements: normative data for the Greek population

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 manufacturers 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.     

Metabolic actions of insulin in men and women

Insulin is an important regulator of glucose, lipid, and protein metabolism. It suppresses hepatic glucose and triglyceride production, inhibits adipose tissue lipolysis and whole-body and muscle proteolysis, and stimulates glucose uptake in muscle. In this review we discuss what is currently known about the control of substrate metabolism by insulin in men and women. The data available so far indicate that women are more sensitive to insulin with regards to glucose metabolism (both in the liver and in muscle), whereas there are no differences between men and women in insulin action on lipolysis. Potential differences exist in the regulation of plasma triglyceride concentration and protein metabolism by insulin and in changes in insulin action in response to stimuli (e.g., weight loss and exercise) that are known to alter insulin sensitivity. However, these areas have not been studied comprehensively enough to draw firm conclusions.     

Decrease in hepatic very‐low‐density lipoprotein–triglyceride secretion after weight loss is inversely associated with changes in circulating leptin

Aim: Although weight loss usually decreases very‐low‐density lipoprotein–triglyceride (VLDL‐TG) secretion rate, the change in VLDL‐TG kinetics is not directly related to the change in body weight. Circulating leptin also declines with weight loss and can affect hepatic lipid metabolism. The aim of this study was to determine whether circulating leptin is associated with weight loss‐induced changes in VLDL‐TG secretion. Methods: Ten extremely obese subjects were studied. VLDL‐TG secretion rate and the contribution of systemic (derived from lipolysis of subcutaneous adipose tissue TG) and non‐systemic fatty acids (derived primarily from lipolysis of intrahepatic and intraperitoneal TG, and de novo lipogenesis) to VLDL‐TG production were determined by using stable isotopically labelled tracer methods before and 1 year after gastric bypass surgery. Results: Subjects lost 33 ± 12% of body weight, and VLDL‐TG secretion rate decreased by 46 ± 23% (p = 0.001), primarily because of a decrease in the secretion of VLDL‐TG from non‐systemic fatty acids (p = 0.002). Changes in VLDL‐TG secretion rates were not significantly related to reductions in body weight, body mass index, plasma palmitate flux, free fatty acid or insulin concentrations. The change in VLDL‐TG secretion was inversely correlated with the change in plasma leptin concentration (r = ?0.72, p = 0.013), because of a negative association between changes in leptin and VLDL‐TG secretion from non‐systemic fatty acids (r = ?0.95, p < 0.001). Conclusions: Weight loss‐induced changes in plasma leptin concentration are inversely associated with changes in VLDL‐TG secretion rate. Additional studies are needed to determine whether the correlation between circulating leptin and VLDL‐TG secretion represents a cause‐and‐effect relationship.     

Effect of zoledronic acid on markers of bone turnover and mineral density in osteoporotic patients with beta-thalassaemia

Osteoporosis has emerged as an important cause of morbidity in patients with thalassemia major. Studies regarding the efficacy of bisphosphonates in thalassemia-induced osteoporosis have yielded conflicting results. We performed this prospective study to evaluate the efficacy of zoledronic acid in osteoporotic patients with thalassemia major. Patients, 29, were given 1 mg zoledronic acid intravenously every 3 months for a total of four doses. Twenty age- and sex-matched healthy blood donors served as controls. Before each infusion and 3 months after the last infusion, we determined serum levels of osteoprotegerin (OPG), N-terminal cross-linking telopeptide of type I collagen (NTX), osteocalcin (OC) and insulin-like growth factor 1 (IGF-1). Bone mineral density (BMD) of the lumbar spine was measured at baseline and after the treatment’s completion. At baseline, OPG did not differ significantly between patients and controls (p=0.2), NTX were higher in patients although not significantly (p=0.139), whereas, OC levels were significantly higher and IGF-1 levels significantly lower in patients than in controls (p<0.001 and p<0.006, respectively). Zoledronic acid administration resulted in a significant decrease in NTX, OC and IGF-1 (p<0.05, p<0.001 and p<0.05, respectively) and in a significant increase in OPG and BMD (p<0.05 for both comparisons). The change in NTX, osteocalcin and IGF-1 became significant as early as 3 months after the first administration of zoledronic acid, while the change in OPG reached significance only after three infusions. Our study supports the effectiveness of bisphosphonates in the treatment of thalassemia-induced osteoporosis.