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P Burckhardt

Publications and source records attributed to P Burckhardt.

At least 19 recordsLinked to original sources
PubMed2006

Validation and reproducibility of a semi-quantitative Food Frequency Questionnaire for use in elderly Swiss women.

OBJECTIVE: The principal aim of this study was to develop a Swiss Food Frequency Questionnaire (FFQ) for the elderly population for use in a study to investigate the influence of nutritional factors on bone health. The secondary aim was to assess its validity and both short-term and long-term reproducibility. DESIGN: A 4-day weighed record (4 d WR) was applied to 51 randomly selected women of a mean age of 80.3 years. Subsequently, a detailed FFQ was developed, cross-validated against a further 44 4-d WR, and the short- (1 month, n = 15) and long-term (12 months, n = 14) reproducibility examined. SETTING: French speaking part of Switzerland. SUBJECTS: The subjects were randomly selected women recruited from the Swiss Evaluation of the Methods of Measurement of Osteoporotic Fracture cohort study. RESULTS: Mean energy intakes by 4-d WR and FFQ showed no significant difference [1564.9 kcal (SD 351.1); 1641.3 kcal (SD 523.2) respectively]. Mean crude nutrient intakes were also similar (with nonsignifcant P-values examining the differences in intake) and ranged from 0.13 (potassium) to 0.48 (magnesium). Similar results were found in the reproducibility studies. CONCLUSION: These findings provide evidence that this FFQ adequately estimates nutrient intakes and can be used to rank individuals within distributions of intake in specific populations.

Aged↗
PubMed2006

Energy and nutrient intake of Swiss women aged 75-87 years.

OBJECTIVE: Reliable data about the nutrient intake of elderly noninstitutionalized women in Switzerland is lacking. The aim of this study was to assess the energy and nutrient intake in this specific population. SUBJECTS: The 401 subjects were randomly selected women of mean age of 80.4 years (range 75-87) recruited from the Swiss SEMOF (Swiss Evaluation of the Methods of Measurement of Osteoporotic Fracture Risk) cohort study. A validated food frequency questionnaire (FFQ) was submitted to the 401 subjects to assess dietary intake. RESULTS: The FFQ showed a mean daily energy intake of 1544 kcal (+/-447.7). Protein intake was 65.2 g (+/-19.9), that is 1.03 g kg(-1) body weight per day. The mean daily intake for energy, fat, carbohydrate, calcium, magnesium, vitamin C, D and E were below the RNI. However, protein, phosphorus, potassium, iron and vitamin B6 were above the RNI. CONCLUSION: The mean nutrient intake of these free living Swiss elderly women was low compared with standards. Energy dense foods rich in carbohydrate, magnesium, calcium, vitamin D and E as well as regular sunshine exposure is recommended in order to optimise dietary intake.

Aged↗
PubMed2005

Gastric banding induces negative bone remodelling in the absence of secondary hyperparathyroidism: potential role of serum C telopeptides for follow-up.

OBJECTIVE: Data about the consequences of laparoscopic adjustable gastric banding (LAGB) on phospho-calcic and bone metabolism remain scarce. SUBJECTS: We studied a group of 37 obese premenopausal women (age: 24-52 y; mean BMI = 43.7 kg/m2) who underwent LAGB. METHODS: Serum calcium, phosphate, alkaline phosphatase, parathormone (PTH), vitamin D3, serum C-telopeptides, IGFBP-3 and IGF-1 were measured at baseline, 6, 12, 18 and 24 months after surgery. Body composition, bone mineral content (BMC) and density (BMD) were measured using dual-X-ray absorptiometry (DXA) at baseline, 6, 12 and 24 months after surgery. RESULTS: There was no clinically significant decrease of calcemia; PTH remained stable. Serum telopeptides increased by 100% (P < 0.001) and serum IGFBP-3 decreased by 16% (P < 0.001) during the first 6 months, and then stabilized, whereas IGF-1 remained stable over the 2 y. BMC and BMD decreased, especially at the femoral neck; this decrease was significantly correlated with the decrease of waist and hip circumference. CONCLUSIONS: We concluded that there was no evidence of secondary hyperparathyroidism 24 months after LAGB. The observed bone resorption could be linked to the decrease of IGFBP-3, although this decrease could be attributable to other confounding factors. Serum telopeptides seem to be a reliable marker of bone metabolism after gastric banding. DXA must be interpreted cautiously during major weight loss, because of the artefacts caused by the important variation of fat tissue after LAGB.

Absorptiometry, Photon↗
PubMed2004

Predictive factors of binge eating disorder in women searching to lose weight.

METHODS: The aim of this study was to detect predictive factors of binge eating disorder (BED) in an out-patient obesity clinic. Eating behaviour, weight history and body composition were assessed in 138 consecutive patients. BED was diagnosed according to the criteria of appendix B of the Diagnostic and Statistical Manual of Mental Disorders. RESULTS: The body mass index (BMI; p < 0.005) and the waist circumference (p < 0.05) were significantly higher in binge patients than in patients without eating disorders. Similar differences were observed between patients who regularly went through weight loss programmes and patients who consulted for the first time. The prevalence of BED increases with the degree of obesity and especially with the number of previous intentional weight loss programmes. A positive and significant correlation was found between the weight cycling syndrome and BMI (p < 0.0001), waist circumference (p < 0.0001) and body fat (p < 0.001). DISCUSSION: The patients with BED present a specific anthropometric profile and a typical behavioural pattern characterized by a higher degree of central obesity and a weight history with a higher number of attempts of weight loss.

Adolescent↗
PubMed2004

Effects of usual nutrient intake and vitamin D status on markers of bone turnover in Swiss adolescents.

OBJECTIVE: To evaluate the effects of nutrient intake and vitamin D status on markers of type I collagen formation and degradation in adolescent boys and girls. DESIGN: Cross-sectional study. SETTING: Canton of Vaud, West Switzerland. SUBJECTS: A total of 92 boys and 104 girls, aged 11-16 y. Data were collected on height, weight, pubertal status (self-assessment of Tanner stage), nutrient intake (3-day dietary record) and fasting serum concentration of 25-hydroxyvitamin D (25OHD), and markers of collagen formation (P1NP) and degradation (serum C-terminal telopeptides: S-CTX). RESULTS: Tanner stage was a significant determinant of P1NP in boys and girls and S-CTX in girls. Of the nutrients examined, only the ratio of calcium to phosphorus (Ca/P) was positively associated with P1NP in boys, after adjustment for pubertal status. 25OHD decreased significantly at each Tanner stage in boys. Overall, 15% of boys and 17% of girls were identified as being vitamin D insufficient (serum 25OHD <30 nmol/l), with the highest proportion of insufficiency at Tanner stage 4-5 (29%) in boys and at Tanner stage 3 (24%) in girls. A significant association was not found between 25OHD and either bone turnover marker, nor was 25OHD insufficiency associated with higher concentrations of the bone turnover markers. CONCLUSIONS: The marked effects of puberty on bone metabolism may have obscured any possible effects of diet and vitamin D status on markers of bone metabolism. The mechanistic basis for the positive association between dietary Ca/P ratio and P1NP in boys is not clear and may be attributable to a higher Ca intake per se, a critical balance between Ca and P intake or higher dairy product consumption. A higher incidence of vitamin D insufficiency in older adolescents may reflect a more sedentary lifestyle or increased utilisation of 25OHD, and suggests that further research is needed to define their requirements. SPONSORSHIP: Nestec Ltd and The Swiss Foundation for Research in Osteoporosis.

Adolescent↗
PubMed2004

Molecular determinants of human adipose tissue: differences between visceral and subcutaneous compartments in obese women.

The adipose tissue is playing an important role in the development of human obesity and its related comorbidities, but little is known about the mechanisms governing its differentiation and proliferation. In this work, we studied the expression of transcription factors involved in fat storage and metabolic regulations in adipose tissue of 50 well-characterized obese women. In multivariate analyses, 80% of c enhancer binding protein alpha (cEBP alpha), c and a sterol regulatory element binding protein 1 (c and a SREBP1), and retinoid X receptor (RXR alpha) levels in sc adipose tissue (SAT) could be explained by other transcription factors. In addition, RXR alpha was the major determinant of peroxisome proliferator and activated receptor-gamma 1 variability in SAT, with the two factors being involved in the determination of the variability of insulin resistance. In contrast, the levels of all these transcription factors, together with various phenotypic and biological characteristics of the patients, seemed to participate only marginally in the regulation of visceral adipose tissue activity. In similar multivariate analyses, they could explain only a minor part of the variability of cEBP alpha, c and a SREBP1, or RXR alpha, suggesting the involvement of other regulators. Overall, our results demonstrate a different regulation of visceral adipose tissue and SAT and a different role of both tissues in insulin resistance and lipid storage.

Adipose Tissue↗
PubMed2004

Impact of preoperative teaching on surgical option of patients qualifying for bariatric surgery.

BACKGROUND: During the last 5 years, the performance of bariatric operations has doubled via our outpatient obesity clinic. Currently, 52% of the patients presenting for weight loss are interested in bariatric surgery. Gastric banding and Roux-en-Y gastric bypass are the two laparoscopic procedures proposed. The aim of this study was to evaluate the impact of preoperative teaching on the patients' surgical option. METHODS: All the candidates for bariatric surgery were submitted to preoperative teaching and those between February 2001 and December 2002 are the subject of this study. The teaching consisted of 3 weekly interactive 2-hour sessions. During the first session, the patients were asked about the type of operation that they had in mind: gastric banding, gastric bypass, or not yet decided. The same questions were repeated at the end of the third session, with an additional possible answer: no surgery. RESULTS: 297 consecutive patients with a BMI >35 kg/m(2) with at least one severe co-morbidity, were submitted to preoperative teaching. 80% of the patients were women. Median age was 41 years. Before teaching, 68 patients (23%) were uncertain, 100 (34%) favored gastric banding, and 129 (43%) wanted a gastric bypass. After education, only 3 patients (1%) remained uncertain, 45 (15%) changed their surgical option, and 27 (9%) declined surgery. The proportion of patients opting for gastric banding decreased from 34% to 20%, whereas those electing bypass increased from 43% to 70%. CONCLUSIONS: Preoperative training provides an informed and better patient selection for bariatric surgery. It helps the patients understand the various surgical options, and makes their decision easier.

Adult↗
PubMed2004

Effects of laparoscopic gastric banding on body composition, metabolic profile and nutritional status of obese women: 12-months follow-up.

BACKGROUND: Obesity is frequently associated with metabolic and cardiovascular co-morbidities and high mortality rates. Besides, because of the increasingly recognized fact that conservative therapy for morbid obesity is associated with an almost 90-95% failure rate in the long term, and probably because of the development of laparoscopic surgery,the demand for bariatric surgery is increasing rapidly. The significant weight loss observed during the first 6-12 months after gastric banding is related to the severe food restriction, related hypercatabolism, and has a potential risk of mineral and vitamin deficiencies. The aim of this study was to evaluate the effects of gastric banding on total body composition, metabolic profile and nutritional status. METHODS: 31 women were studied with median age 36 years (range 25-52), body weight 118.6 kg (range 98-156), BMI 43.6 kg/m(2) (range 36-56 kg/m(2)), percentage of excess body weight (%EW) of 107% (range 72- 166%), waist 115 cm (range 98-132) and hip 138 cm (range 119-155). Total body composition was measured before, 6 and 12 months after laparoscopic gastric banding, using dual-energy x-ray absorptiometry. Metabolic and nutritional profile were evaluated before and 1, 3, 6, 9 and 12 months postoperatively. RESULTS: There was a 23.3% reduction of total body weight and 36.8% reduction of body fat. Unfortunately we also observed a reduction of Fat Free Mass (FFM) of 9.6%. In addition, the major determinants of weight loss were the initial body weight and abdominal distribution of fat mass. Reduction of FFM was positively correlated with the rapidity of weight loss. A significant improvement of glucidic profile was observed, with disappearance of impaired fasting glucose, and normalization of the values of triglycerides in all patients. The prevalence of the metabolic syndrome decreased from 89% in preoperative conditions to 15% 1 year after gastric banding. No major nutritional deficiencies was found following gastric banding. CONCLUSIONS: This prospective study suggests that the first 6 months postoperatively are crucial for weight loss and changes in body composition. Furthermore, the significant reduction of body weight is accompanied by an important improvement of biological abnormalities.

Adult↗
PubMed2003

Intravenous ibandronate in men with osteoporosis: an open pilot study over 2 years.

In the treatment of osteoporosis, the tolerance of oral bisphosphonates is often low. The high potency of ibandronate allows iv bolus injections that can be repeated every 2 to 3 months. However, the best dose and time interval of the treatment with iv ibandronate is still debated. Efficacy of 2-mg ibandronate injected every 3 months was tested in men with osteoporosis over 2 yr, in a prospective, open study. Fourteen men with primary osteoporosis, mean age 57 +/- 12 yr (range: 40-73), received 2-mg ibandronate iv every 3 months over 2 yr. All got 1 g/day calcium and 880 UI/day vitamin D for 2 yr. Bone mineral density (BMD) increased after 2 yr by 6.7 +/- 1.5% (mean change +/- SEM) at lumbar spine (p<0.001), by 3.2 +/- 08% at trochanter (p<0.001) and by 1.4 +/- 1.1% at femoral neck (ns). Serum beta-crosslaps and osteocalcin decreased significantly by 30-45 and 30%, respectively, during the 2 yr of treatment. Serum calcium increased from the lower to the middle tertile of the normal range during the 2 yr of the study. The observed decrease of bone remodelling and the increase of BMD are of the same magnitude as those described with oral bisphosphonates. The increase of plasma calcium confirms the positive effect of the supplementation with calcium and vitamin D. These results suggest that 3 months are a good interval between two doses of iv ibandronate, when 2 mg are given.

Adult↗
PubMed2003

Reconstitution of telomerase activity combined with HPV-E7 expression allow human preadipocytes to preserve their differentiation capacity after immortalization.

Overexpression of SV40 T-antigen (SV40 T-Ag) has been widely used to overcome replicative senescence of human primary cells and to promote cell immortalization. However, in the case of certain cell types, such as preadipocytes, the differentiation process of immortalized cells is blocked by SV40 T-Ag expression. In this study, human telomerase reverse transcriptase (hTERT) and papillomavirus E7 oncoprotein (HPV-E7) genes were coexpressed in human preadipocytes to test whether this combination could maintain cell differentiation capacity after immortalization. We demonstrated that the HPV-E7/hTERT expressing preadipocytes displayed an indefinite life span. Interestingly, immortalized cells were diploid and presented no chromosomic alterations. These immortalized cells were able to accumulate and hydrolyze intracellular triglycerides and to express adipocyte markers. These data demonstrate, for the first time, that coexpression of hTERT and HPV-E7 in human preadipocytes allows cells not only to display an indefinite life span but also to retain their capacity to differentiate.

Adipocytes↗
PubMed2003

Bone metabolism and risk of secondary hyperparathyroidism 12 months after gastric banding in obese pre-menopausal women.

OBJECTIVE: To evaluate, during the first postoperative year in obese pre-menopausal women, the effects of laparoscopic gastric banding on calcium and vitamin D metabolism, the potential modifications of bone mineral content and bone mineral density, and the risk of development of secondary hyperparathyroidism. SUBJECTS: Thirty-one obese pre-menopausal women aged between 25 and 52 y with a mean body mass index (BMI) of 43.6 kg/m(2), scheduled for gastric banding were included. Patients with renal, hepatic, metabolic and bone disease were excluded. METHODS: Body composition and bone mineral density (BMD) were measured at baseline, 6 and 12 months after gastric banding using dual-energy X-ray absorptiometry. Serum calcium, phosphate, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltransferase, bilirubin, urea, creatinine, uric acid, proteins, parathormone, vitamin D(3), IGF-1, IGF-BP3 and telopeptide, as well as urinary telopeptide, were measured at baseline and 1, 3, 6, 9 and 12 months after surgery. RESULTS: After 1 y vitamin D3 remained stable and PTH decreased by 12%, but the difference was not significant. Serum telopeptide C increased significantly by 100% (P<0.001). There was an initial drop of the IGF-BP3 during the first 6 months (P<0.05), but the reduction was no longer significant after 1 y. The BMD of cortical bone (femoral neck) decreased significantly and showed a trend of a positive correlation with the increase of telopeptides (P<0.06). The BMD of trabecular bone, at the lumbar spine, increased proportionally to the reduction of hip circumference and of body fat. CONCLUSION: There is no evidence of secondary hyperparathyroidism 1 y after gastric banding. Nevertheless biochemical bone markers show a negative remodelling balance, characterized by an increase of bone resorption. The serum telopeptide seems to be a reliable parameter, not affected by weight loss, to follow up bone turnover after gastroplasty.

Adult↗
PubMed2003

Comparison of three bone ultrasounds for the discrimination of subjects with and without osteoporotic fractures among 7562 elderly women.

UNLABELLED: Bone ultrasound measures (QUSs) can assess fracture risk in the elderly. We compared three QUSs and their association with nonvertebral fracture history in 7562 Swiss women 70-80 years of age. The association between nonvertebral fracture was higher for heel than phalangeal QUS. INTRODUCTION: Because of the high morbidity and mortality associated with osteoporotic fractures, it is essential to detect subjects at risk for such fractures with screening methods. Because quantitative bone ultrasound (QUS) discriminated subjects with osteoporotic fractures from controls in several cross-sectional studies and predicted fractures in prospective studies, QUS could be more practical than DXA for screening. MATERIAL AND METHODS: This cross-sectional and retrospective multicenter (10 centers) study was performed to compare three QUSs (two heel ultrasounds: Achilles+ [GE-Lunar] and Sahara [Hologic]; the phalanges: ultrasound DBM sonic 1200 [IGEA]) for determining by logistic regression nonvertebral fracture odds ratio (OR) in a sample of 7562 Swiss women, 75.3 +/- 3.1 years of age. The two heel QUSs measured the broadband ultrasound attenuation (BUA) and the speed of sound (SOS). In addition, Achilles+ calculated the stiffness index (SI) and the Sahara calculated the quantitative ultrasound index (QUI) from BUA and SOS. The DBM sonic 1200 measured the amplitude-dependent SOS (AD-SOS). RESULTS: Eighty-six women had a history of a traumatic hip fracture after the age of 50, 1594 had a history of forearm fracture, and 2016 had other nonvertebral fractures. No fracture history was reported by 3866 women. Discrimination for hip fracture was higher than for the other nonvertebral fractures. The two heel QUSs had a significantly higher discrimination power than the QUSs of the phalanges, with standardized ORs, adjusted for age and body mass index, ranging from 2.1 to 2.7 (95% CI = 1.6, 3.5) compared with 1.4 (95% CI = 1.1, 1.7) for the AD-SOS of DBM sonic 1200. CONCLUSION: This study showed a high association between heel QUS and hip fracture history in elderly Swiss women. This could justify integration of QUS among screening strategies for identifying elderly women at risk for osteoporotic fractures.

Age Factors↗
PubMed2003

Rising role of obesity surgery caused by increase of morbid obesity, failure of conventional treatments and unrealistic expectations: trends from 1997 to 2001.

BACKGROUND: The authors analyzed the trends in anthropometric and behavioral characteristics among patients seeking weight loss and the trends in choice of treatments, between 1997 and 2001 in an outpatient obesity clinic. PATIENTS AND METHODS: 138 and 128 consecutive patients attending the out-patient obesity clinic at University Hospital of Lausanne were screened in 1997 and in 2001 respectively. Eating habits, body composition and treatment used were assessed. RESULTS: Median BMI was 35 kg/m2 in 1997 and 38 kg/m2 in 2001 (P <0.001) and waist circumference was 99 cm and 111 cm respectively (P <0.001). This increase in the average body weight involved especially patients <30 years old (P <0.01). Morbid obesity increased by 16% (P <0.01), and prevalence of abdominal obesity by 13% (P < 0.05). The median desired weight loss increased significantly from 25% to 29% (P <0.05). 64% of the patients in 1997 and 83% in 2001 (P <0.01) hoped for a weight loss of 20% of their baseline weight. Motivation to lose weight for esthetic reasons was found in 81% of the women and 55% of the men in 1997 (P <0.01), while in 2001 the percentage was 89 and 43 respectively (P <0.001). CONCLUSION: In spite of the increasing access to weight loss programs, we found that the patients are more severely obese, especially those <30 years old, and have more unrealistic expectations of weight loss. This may explain the doubling of the patients treated by surgery.

Adult↗
PubMed2003

Nutritional status using the Mini Nutritional Assessment questionnaire and its relationship with bone quality in a population of institutionalized elderly women.

Malnutrition, a risk factor for osteoporotic fractures, is frequent in elderly people and, is underdiagnosed and undertreated. There are only few studies on the nutritional status of elderly people in Europe. The Mini Nutritional Assessment (MNA) is a non invasive and validated questionnaire to evaluate nutritional status in elderly people, classified in three groups: 1 degree score < 17: malnourished, 2 degrees score >17 and < 24: at risk of malnutrition, 3 degrees score >24: well-nourished, with a maximum of 30 points. Quantitative ultrasound of bone (QUS) is a method for assessing quality of bone which can be easily performed in nursing homes. Therefore, these two tests allowed to study the relationships between nutritional status and ultrasonic parameters of bone in 78 institutionalized women aged 86 +/- 6 years, living in 11 nursing homes around Lausanne (Switzerland). All were assessed by the MNA, had a measurement of the tricipital skin fold and of the grip strength. Functional status was evaluated by the scale "Activity of Daily Living" (ADL), and serum albumin level was measured when permitted. All had QUS of the calcaneus (with an Achilles, GE Lunar). The measured parameters are the Broadband Ultrasound Attenuation (BUA), attenuation of a band of ultrasonic frequencies through the medium, expressed in dB/MHz, and the Speed of Sound (SOS), speed of the ultrasounds through the medium, expressed in m/s. A third parameter, the stiffness index (SI), expressed as a percentage of the values obtained by the manufacturer in a young population and derived from BUA and SOS, was calculated automatically : SI = (0.67xBUA) + (0.28xSOS) - 420, expressed in percent compared to a young adult population (%YA). Fifteen percent of the women were undernourished and 58% were at risk of malnutrition. As expected, compared with the well-nourished minority, undernourished subjects had significant lower body mass index (BMI), tricipital skin fold (TSF), ADL score and albumin level (p < 0,01). The subjects "at risk of malnutrition" had significant lower BMI, ADL score (p < 0.01), tricipital skin fold and serum albumin (p < 0.05). Ultrasound parameters were low independently of the nutritional status. MNA score correlated significantly with tricipital skin fold (r = 0.508, p < 0.01), ADL (r = 0.538, p < 0.01) and albumin serum level (r = 0.409, p = 0.01). There was a trend for a correlation between the MNA and the ultrasound parameter BUA (r = 0.207, p = 0.07), whereas no correlation was found with SOS and SI. A multivariate analysis showed that tricipital skin fold and ADL explained 61% of the variance of the MNA. In conclusion, using simple and non invasive methods, this study showed that malnutrition and osteoporosis are frequent in institutionalized elderly persons in our country, and the ultrasound parameters are influenced by many others factors in addition to nutrition, especially at this age and in elderly residents of nursing homes.

Activities of Daily Living↗
PubMed2003

Long term effects of a single dose of intravenous Ibandronate.

For defining the optimal regimen of a treatment of osteoporosis with an intravenous bisphosphonate one needs to know the duration of action of a single dose of the given drug. This allows us to establish the frequency by which a given dose has to be administered for obtaining a sufficient suppression of bone resorption over a longer period. In this study 1 and 2 mg Ibandronate were given as a single i.v. injection to young normal men and to healthy postmenopausal women on a free diet and with no treatment or supplements, and the markers of bone metabolism, as well as BMD, were followed for 6 months. Urinary C-telopeptides decreased by 81-95% 1 week after the injection and remained significantly decreased for 2 weeks after 1 mg Ibandronate, and for 4 months after 2 mg. In men, PTH increased by 80% at one week and remained significantly increased for 2 weeks, after 1mg and 2 mg Ibandronate. Plasma osteocalcin decreased slowly over 2 months in all 3 groups by 22%. Alkaline phosphatase showed similar, but not significant changes. In conclusion, the inhibition of bone resorption induced by 1 mg Ibandronate i.v. does not exceed 1 month and does not allow 3 month intervals in the treatment of osteoporosis, while 2 mg cover 3 months at least.

Journal Article↗
PubMed2002

Quality controls for two heel bone ultrasounds used in the Swiss Evaluation of the Methods of Measurement of Osteoporotic Fracture Risk Study.

Because of the important morbidity and mortality associated with osteoporosis, it is essential to detect subjects at risk by screening methods, such as bone quantitative ultrasounds (QUSs). Several studies showed that QUS could predict fractures. None, however, compared prospectively different QUS devices, and few data of quality controls (QCs) have been published. The Swiss Evaluation of the Methods of Measurement of Osteoporotic Fracture Risk is a prospective multicenter study that compared three QUSs for the assessment of hip fracture risk in a population of 7609 women age >/=70 yr. Because the inclusion phase lasted 20 mo, and because 10 centers participated in this study, QC became a major issue. We therefore developed a QC procedure to assess the stability and precision of the devices, and for their cross-calibration. Our study focuses on the two heel QUSs. The water bath system (Achilles+) had a higher precision than the dry system (Sahara). The QC results were highly dependent on temperature. QUS stability was acceptable, but Sahara must be calibrated regularly. A sufficient homogeneity among all the Sahara devices could be demonstrated, whereas significant differences were found among the Achilles+ devices. For speed of sound, 52% of the differences among the Achilles+ was explained by the water s temperature. However, for broadband ultrasound attenuation, a maximal difference of 23% persisted after adjustment for temperature. Because such differences could influence measurements in vivo, it is crucial to develop standardized phantoms to be used in prospective multicenter studies.

Calcaneus↗
PubMed2001

Diet acids and alkalis influence calcium retention in bone.

The urine-acidifying properties of food constituents depend on their content of non-oxidizable acids or precursors. Acidifying constituents such as animal proteins may negatively affect calcium metabolism and accelerate bone resorption, thus representing an aggravating factor for osteoporosis. This four-period, double-crossover study investigated whether a diet intervention specifically focused on acid load could modify calcium metabolism in humans. Eight healthy volunteers underwent a four-day metabolic preparation with two types of diets, one rich in acid ash-forming nutrients, and one providing base-forming nutrients (including bicarbonate-rich mineral water), both having similar contents of calcium, phosphate, sodium, proteins and calories. On the fourth day, a single oral dose of 1 g calcium was given, either as carbonate or as gluconolactate. Serial blood and urine samples revealed that the diet affected blood pH (average difference 0.014, p=0.002) and urine pH (average difference 1.02, p<0.0001) in the expected direction, but had no influence on the absorption of the calcium supplement. The acid-forming diet increased urinary calcium excretion by 74% when compared with the base-forming diet (p<0.0001), both at baseline and after the oral calcium load, and C-telopeptide excretion by 19% (p=0.01), suggesting a skeletal origin for the excess calcium output. This observation confirms that renally excreted acids derived from food influence calcium metabolism, and that alkalizing nutrients inhibit bone resorption. Further studies are needed to determine the clinical impact of dietary counseling for avoiding diet acids as a preventive measure against osteoporosis.

Acids↗