Biomedical subjects

Rajata Rajatanavin

Publications and source records attributed to Rajata Rajatanavin.

At least 19 recordsLinked to original sources

PubMed2006

Association between bone mineral density and erythropoiesis in Thai children and adolescents with thalassemia syndromes.

Increased marrow erythropoiesis in patients with thalassemia syndromes results in the expansion of bone marrow cavities and consequently decreases bone tissues, leading to osteoporosis. Whether the soluble transferrin receptor (sTfR), a marker of erythropoietic activity, correlates with the bone mineral density (BMD) in thalassemic patients has not previously been addressed. Forty-six children and adolescents with thalassemia syndromes, who were either not transfused or suboptimally transfused, were studied. BMD was determined by dual-energy X-ray absorptiometry. Blood samples were obtained in order to determine sTfR and hemoglobin. The patients were categorized into four groups: 1, beta-thalassemia/hemoglobin E (beta-thal/E) with transfusion-dependency (TD) (n = 18); 2, beta-thal/E with transfusion-independency (TI) (n = 15); 3, beta-thalassemia major (beta-major) (n = 6); 4, hemoglobin H (HbH) (n = 7). All patients had normal serum free thyroxine (FT4) and thyroid-stimulating hormone (TSH), and intact parathyroid hormone (PTH), serum calcium (Ca), phosphate (P), and 25-OH-vitamin D levels. The BMD of patients in the beta-major and beta-thal/E with TD groups were not significantly different. In comparison with the beta-major and beta-thal/E with TD groups, the beta-thal/E with TI and HbH groups had significantly higher BMD of the total body (TB), femoral neck (FN), and lumbar spine (LS), as well as higher levels of hemoglobin. In contrast, the sTfR levels of the beta-major, beta-thal/E with TI, and HbH groups were significantly lower than those of the beta-thal/E with TD group. The BMD of TB, FN, and LS was negatively correlated with the sTfR level, but positively correlated with the hemoglobin level. In conclusion, increased marrow erythropoiesis is one of the major determinants of reduced bone mass in thalassemic patients with either no transfusion or suboptimal transfusion.

Adolescent↗

PubMed2006

A risk score for predicting incident diabetes in the Thai population.

OBJECTIVE: The objective of this study was to develop and evaluate a risk score to predict people at high risk of diabetes in Thailand. RESEARCH DESIGN AND METHODS: A Thai cohort of 2,677 individuals, aged 35-55 years, without diabetes at baseline, was resurveyed after 12 years. Logistic regression models were used to identify baseline risk factors that predicted the incidence of diabetes; a simple model that included only those risk factors as significant (P < 0.05) when adjusted for each other was developed. The coefficients from this model were transformed into components of a diabetes score. This score was tested in a Thai validation cohort of a different 2,420 individuals. RESULTS: A total of 361 individuals developed type 2 diabetes in the exploratory cohort during the follow-up period. The significant predictive variables in the simple model were age, BMI, waist circumference, hypertension, and history of diabetes in parents or siblings A cutoff score of 6 of 17 produced the optimal sum of sensitivity (77%) and specificity (60%). The area under the receiver-operating characteristic curve (AUC) was 0.74. Adding impaired fasting glucose or impaired glucose tolerance status to the model slightly increased the AUC to 0.78; adding low HDL cholesterol and/or high triglycerides barely improved the model. The validation cohort demonstrated similar results. CONCLUSIONS: A simple diabetes risk score, based on a set of variables not requiring laboratory tests, can be used for early intervention to delay or prevent the disease in Thailand. Adding impaired fasting glucose or impaired glucose tolerance or triglyceride and HDL cholesterol status to this model only modestly improves the predictive ability.

Adult↗

PubMed2006

Prevalence of osteoporosis in Thai men.

BACKGROUND: Osteoporosis is a growing health problem not only in women but also in men. However, there is a scarcity of epidemiologic data to study osteoporosis in Thai men. OBJECTIVES: To examine the bone mineral density (BMD) and to determine the prevalence of osteoporosis in Thai men. MATERIAL AND METHOD: A total of 412 men (159 from Bangkok and 253 from Khon Kaen, respectively) averaging 51 +/- 16 years of age, were measured for BMD at the femoral neck and lumbar spine by dual energy X-ray absorptiometry (LUNAR Corporation, WI, USA). RESULTS: The peak BMD was observed in men 20-29 years of age at both the femoral neck (mean +/- SD, 1.10 +/- 0.15 g/cm2) and lumbar spine (mean +/- SD, 1.17 +/- 0.13 g/cm2). The prevalence of osteoporosis in the entire group of subjects was 12.6, 4.6 and 3.9 per cent at the femoral neck, lumbar spine and both sites, respectively. The prevalence of osteoporosis increased with advancing age and was significantly higher at the femoral neck in urban men than rural men (18.2 vs 9.2 per cent, p < 0.05) but comparable at the lumbar spine (5.0 vs 4.3 per cent, p = 0.81). The correlation between femoral neck and lumbar spine BMDs was 0.53 (p < 0.001). In univariate analysis, increased age, lower weight and lesser height were each associated with lower femoral neck BMD, whereas only lower weight and lesser height were associated with lower lumbar spine BMD. However, when the three factors were entered simultaneously, only increased age and lower weight were significantly associated with lower femoral neck BMD and only lower weight had a significant association with lower lumbar spine BMD. CONCLUSION: The present study demonstrated descriptive BMD data, normal BMD reference values for diagnosis and reported the prevalence of osteoporosis in Thai men.

Absorptiometry, Photon↗

PubMed2006

Defining obesity by body mass index in the Thai population: an epidemiologic study.

The objective of this study was to develop cut-off values and evaluate the accuracy of body mass index (BMI) in the definition of obesity in the Thai population. A cross-sectional, epidemiologic study in 340 men and 507 women aged 50 +/- 16 yr (mean +/- SD; range: 20-84 yr), were sampled by stratified clustering sampling method. Body composition, including percentage body fat (%BF), was measured by dual energy X-ray absorptiometry (GE Lunar Corp, Madison, WI). BMI was obtained by dividing weight (in kg) by height (in m2). The "golden standard "for defining obesity was %BF > or =25% in men and %BF > or =35% in women. The %BF-based prevalence of obesity in men and women was 18.8% and 39.5%, respectively. However, using the BMI cut-off of > or =30, only 2.9% of men and 8.9% of women were classified as obese. In the cubic regression model, BMI was a significant predictor of %BF, such that in men a BMI of 27 kg/m2 would predict a %BF of 25%, and in women a BMI of 25 kg/m2 would correspond to a %BF of 35%. The area under the receiver operating characteristic curve for BMI was approximately 0.87 (95% CI: 0.82-0.92) and 0.86 (95% CI: 0.83-0.90) in men and women, respectively. In conclusion, for the Thai population, BMI is a reasonably useful indicator of obesity; however, the cut-off values of BMI for diagnosing obesity should be lowered to 27 kg/m2 in men and 25 kg/m2 in women.

Absorptiometry, Photon↗

PubMed2006

Relationship of body composition and circulatory adiponectin to bone mineral density in young premenopausal women.

OBJECTIVE: Adiponectin is a recently discovered hormone secreted by adipocytes. Adiponectin plays an important role in the regulation of insulin sensitivity as well as the propensity to inflammation and atherosclerosis. In the present study, the authors explore the relationship between adiponectin and bone mass in premenopausal women. The relationship of fat mass compared to lean body mass to bone mass was also investigated MATERIAL AND METHOD: Two hundred premenopausal women aged between 20 and 40 years were studied. Bone mineral density (BMD) was measured at L2-4 and femoral neck by dual-energy X-ray absorptiometry (DEXA). Serum adiponectin concentrations were measured by radioimmunoassay. RESULTS: At the lumbar spines, factors associated with BMD were age (p < 0.01) and lean body mass (p < 0.001). No independent association with fat mass was demonstrated Likewise, at the femoral neck, only lean body mass was related to BMD (p < 0. 01). In terms of the relation of serum adiponectin to BMD, no association of serum adiponectin to BMD at the lumbar spines or femoral neck was found CONCLUSION: Altogether, the present findings do not suggest the independent role of adiponectin in the accrual of bone mass in females, although such a role still cannot be excluded in men or postmenopausal women.

Adiponectin↗

PubMed2006

Association between waist circumference and percentage body fat among rural Thais.

OBJECTIVE: Determine the association between waist circumference (WC) and percentage body fat (%BF) and to develop cut-off values and evaluate the accuracy of WC in the definition of obesity in rural Thai population. MATERIAL AND METHOD: A cross-sectional, epidemiologic study in 181 men and 255 women aged 50+/-16 yr (mean+/-SD; range: 20-84 yr) sampled by stratified clustering sampling method, was designed. Percentage body fat was measured by dual energy X-ray absorptiometry (GE Lunar Corp, Madison, WI). The "golden standard"for defining obesity was%BF > or = 25 in men and%BF > or = 35 in women. Waist circumference in centimeter was measured. RESULTS: In this study, the %BF-based prevalence of obesity in men and women was 8.3% and 44%, respectively. However using the WC cut-off (WHO) of 102 cm in men and 88 cm in women, only 1.7% of men and 24% of women were classified as obese. WC was a significant predictor of %BF, such that in men, a WC of 93 cm would predict a %BF of25%, and in women a WC of 84 cm would correspond to a %BF of 35%. The area under the receiver operating characteristic curve was 0. 87 and 0. 88 in men and women, respectively. In conclusion, waist circumference is a reasonably useful indicator of obesity. CONCLUSION: The cut-off values of WC for diagnosing obesity should be lower in Thailand than in Western countries.

Adult↗

PubMed2005

Contribution of lean tissue mass to the urban-rural difference in bone mineral density.

While the urban-rural difference in bone mineral density (BMD) has been shown in some, but not all, Western populations, such a difference and the reason for the difference is largely unknown, particularly in developing countries. This cross-sectional, epidemiologic study was designed to examine the hypothesis that differences in measures of body composition such as lean mass (LM) and fat mass (FM) contribute to the urban-rural difference in BMD. Lean mass, fat mass, lumbar spine and femoral neck BMD were measured by DXA (GE Lunar Corp, Wis.) in 411 urban (Bangkok city) and 436 rural (Khon Kaen province) Thai subjects, aged 20-84 years. Rural men and women had significantly higher LM and lower FM than their urban counterparts. In multiple linear regression analysis, age, LM, menopausal status (in women) and residence were independent determinants of BMD. After adjusting for age, menopause and LM, rural subjects were found to have significantly higher femoral neck BMD, but not lumbar spine BMD, than urban subjects. Furthermore, to alleviate the potential effect of multicolinearity of LM and FM, each rural subject was matched with each urban subject for FM and age, which resulted in 46 pairs of men and 91 pairs of women. In this matched-pair analysis, the femoral necks in rural men and women were, respectively, 7.3+/-2.1% (mean+/-SE; P<0.01) and 6.3+/-2.8% (P<0.02) higher than in urban men and women. The urban-rural difference in LM accounted for approximately 23 and 5% of the urban-rural difference in femoral neck BMD in men and women, respectively. These data are thus consistent with the hypothesis that the urban-rural difference in BMD at a weight-bearing site is in part associated with the urban-rural difference in lean mass.

Absorptiometry, Photon↗

PubMed2005

Effect of urbanization on bone mineral density: a Thai epidemiological study.

BACKGROUND: The incidence of fractures in rural populations is lower than in urban populations, although the reason for this difference is unclear. This cross-sectional study was designed to examine the difference in bone mineral density (BMD), a primary predictor of fracture risk, between urban and rural Thai populations. METHODS: Femoral neck and lumbar spine BMD was measured by dual-energy X-ray absorptiometry (GE Lunar, Madison, WI) in 411 urban and 436 rural subjects (340 men and 507 women), aged between 20 and 84 years. Body mass index (BMI) was calculated from weight and height. RESULTS: After adjusting for age and body weight in an analysis of covariance model, femoral neck BMD in rural men and women was significantly higher than those in urban men and women (P < 0.001), but the difference was not observed at the lumbar spine. After stratifying by sex, age group, and BMI category, the urban-rural difference in femoral neck BMD became more pronounced in men and women aged <50 years and with BMI > or = 25 kg/m2. CONCLUSIONS: These data suggest that femoral neck BMD in rural men and women was higher than their counterparts in urban areas. This difference could potentially explain part of the urban-rural difference in fracture incidence.

Absorptiometry, Photon↗

PubMed2005

Prediction of percentage body fat in rural thai population using simple anthropometric measurements.

OBJECTIVE: To develop and validate sex-specific equations for predicting percentage body fat (%BF) in rural Thai population, based on BMI and anthropometric measurements. RESEARCH METHODS AND PROCEDURES: %BF (DXA; GE Lunar Corp., Madison, WI) was measured in 181 men and 255 women who were healthy and between 20 and 84 years old. Anthropometric measures such as weight (kilograms), height (centimeters), BMI (kilograms per meter squared), waist circumference (centimeters), hip circumference (centimeters), thickness at triceps skinfold (millimeters), biceps skinfold (millimeters), subscapular skinfold (millimeters), and suprailiac skinfold (millimeters) were also measured. The sample was randomly divided into a development group (98 men and 125 women) and a validation group (83 men and 130 women). Regression equations of %BF derived from the development group were then evaluated for accuracy in the validation group. RESULTS: The equation for estimating %BF in men was: %BF(men) = 0.42 x subscapular skinfold + 0.62 x BMI - 0.28 x biceps skinfold + 0.17 x waist circumference - 18.47, and in women: %BF(women) = 0.42 x hip circumference + 0.17 x suprailiac skinfold + 0.46 x BMI - 23.75. The coefficient of determination (R2) for both equations was 0.68. Without anthropometric variables, the predictive equation using BMI, age, and sex was: %BF = 1.65 x BMI + 0.06 x age - 15.3 x sex - 10.67 (where sex = 1 for men and sex = 0 for women), with R2 = 0.83. When these equations were applied to the validation sample, the difference between measured and predicted %BF ranged between +/-9%, and the positive predictive values were above 0.9. DISCUSSION: These results suggest that simple, noninvasive, and inexpensive anthropometric variables may provide an accurate estimate of %BF and could potentially aid the diagnosis of obesity in rural Thais.

Abdomen↗

PubMed2005

Biochemical markers of bone formation in Thai children and adolescents.

The measurement of biochemical markers of bone turnover is essential in the study of skeletal metabolism in health and diseases. Due to variations in the rate of bone growth in different age groups and possible ethnic differences, age-specific reference ranges for biochemical markers should be established in a particular pediatric population. In this study, biochemical markers of bone formation, bone-specific alkaline phosphatase (BAP), and osteocalcin (OC) in healthy Thai children and adolescents aged 9 to 18 years were evaluated in relation to their ages and pubertal development. Serum BAP levels in boys increased with age and peaked at about 12 to 13 years. In contrast, there was a progressive decline of serum BAP levels with advancing age in girls older than 9 years. Serum OC also increased with age and reached a peak at ages 12 and 13 years in girls and boys, respectively. In addition, both serum BAP and OC levels also varied with pubertal stages. The BAP levels in boys increased sharply at pubertal stage 3 and decreased at pubertal stage 5. In girls, the BAP levels showed a fairly constant high level up to stage 3, followed by a remarkable decrease thereafter. The OC levels in boys increased sharply at pubertal stage 4 and decreased thereafter. In girls, OC started to increase at pubertal stage 3 with no subsequent changes. The levels of serum BAP and OC were higher in boys than in girls at pubertal stages 3 to 5 and at stages 2, 4, and 5, respectively. Moreover, only serum BAP level showed significant positive correlation with height velocity in both genders. In multiple regression analyses, gender, age, and pubertal stage were consistently correlated with both serum BAP and OC levels. In summary, male and female adolescents have different patterns of changes in biochemical markers of bone formation.

Adolescent↗

PubMed2005

Exogenous subclinical hyperthyroidism during adolescence: effect on peak bone mass.

BACKGROUND: Chronic subclinical hyperthyroidism induced by suppressive doses of L-thyroxine (L-T4) therapy, so-called exogenous subclinical hyperthyroidism, may cause diminished bone mass in postmenopausal women. The effect of subclinical hyperthyroidism during childhood and adolescence on peak bone mass, however, has not been evaluated. OBJECTIVE: To determine whether exogenous subclinical hyperthyroidism during adolescence, the period of critical bone mass acquisition, would reduce peak bone mass. PATIENTS AND METHODS: Eighteen female adolescents and young adults with Hashimoto's thyroiditis and euthyroid goiter (aged 22.4 +/- 4.4 years) who had been treated with suppressive doses of L-T4, 127.5 +/- 23.7 microg/day, during adolescence (age at onset of subclinical hyperthyroidism, 14.2 +/- 1.5 years) for 6.3 +/- 3.4 years were enrolled in the study. Twenty-nine healthy female volunteers matched for age, weight, height and body mass index served as the controls. Bone mineral density (BMD) was measured by dual energy X-ray absorptiometry. RESULTS: BMD of the lumbar spine, radius, Ward's triangle and total body were comparable in the two groups. In contrast, BMD of the femoral neck, trochanter and shaft of patients was slightly higher than those of controls. There were no correlations between BMD values and clinical parameters. CONCLUSION: Exogenous subclinical hyperthyroidism during adolescence has no demonstrable detrimental effect on peak bone mass attainment.

Adolescent↗

PubMed2005

The effect of cigarette smoking on the severity of periodontal disease among older Thai adults.

BACKGROUND: The aim of this study is to determine the effect of cigarette smoking on the severity of periodontitis in a cross-sectional study of older Thai adults. METHODS: The study population consisted of 1,960 subjects (age 50 to 73 years old). All subjects received both medical and dental examinations. Periodontal examinations, including plaque score, probing depth, and clinical attachment level, were done on all teeth present in two diagonal quadrants. Sociodemographic characteristics and smoking status were obtained by questionnaires. Multinomial logistic regression was used to address the association between cigarette consumption and mean clinical attachment level. RESULTS: In this study population, 48.7% were non-smokers, 14.4% were current smokers, and 36.9% were former smokers. Current smokers had higher percentage of sites with plaque, deeper mean probing depth, and greater mean clinical attachment level than former smokers and non-smokers. The odds of having moderate and severe periodontitis for current smokers were 1.7 and 4.8 times greater than non-smokers, respectively. Former smokers were 1.8 times more likely than non-smokers to have severe periodontitis. Quitting smoking reduced the odds of having periodontitis. For light smokers (<15 packyear), the odds for severe periodontitis reverted to the level of non-smokers when they had quit smoking for > or =10 years. For moderate and heavy smokers (> or =15 packyear), the odds of having severe periodontitis did not differ from those of non-smokers when they had quit smoking for > or =20 years. CONCLUSIONS: There was a strong association between cigarette smoking and the risk of periodontitis among older Thai adults. Quitting smoking appears to be beneficial to periodontal health.

Adult↗

PubMed2005

Association of circulating leptin with bone mineral density in males and females.

Leptin, a hormone produced by fat cells, possesses several physiological functions not limited to energy balance. Recently, leptin has been shown to inhibit bone formation through its action at the hypothalamus. In the present study, the authors explored the association of leptin with bone mineral density (BMD) in men and women according to menopausal status. Subjects consisted of 75 men, 51 premenopausal women and 63 postmenopausal women aged 20-80 years. All were healthy and did not take medication which may affect bone metabolism. BMD was measured at L2-4 and femoral neck by DEXA. Serum leptin concentrations were measured by radioimmunoassay. Serum leptin in males was independently related to BMD at L2-4 (r = -0.36, p < 0.05) and the femoral neck (r = -0.32, p < 0.05) in a multiple linear regression model with age, body mass index (BMI), serum free testosterone, estradiol and leptin as independent variables. In premenopausal women, serum leptin correlated negatively to L2-4 (r = -0.29, p < 0.01) and femoral neck BMD (r = -0.29, p < 0.05) independently of age and BMI. However, in postmenopausal women, no association of leptin with BMD was found after controlling for age and BMI. The authors concluded that circulating leptin is negatively associated with BMD in men and premenopausal women, but not in postmenopausal women. The negative associations found in both premenopausal women and men in the present study strengthen the notion that leptin may inhibit bone formation during the accumulation of bone mass early in life

Adult↗

PubMed2005

Estimated volumetric bone mineral density in a rural Thai men and women: Khon Kaen Osteoporosis Study (KKOS).

The authors examined the areal bone mineral density (aFNBMD) and estimated volumetric bone mineral density at the femoral neck (vFNBMD) in rural Thai men and women. A total of 181 men and 255 women, between 20 and 84 years of age, living in rural areas of Khon Kaen province, were randomly selected. Areal FNBMD and estimated v FNBMD were determined using dual energy X-ray absorptiometry (DPX-IQ, GE Lunar Corp, Madison, WI). Men had a significantly higher aFNBMD than women, whereas the estimated vFNBMD was similar regardless of sex. The peak for the aFNBMD vs. vFNBMD was observed between 20 and 29 vs. 30 and 39 years of age in men and women, respectively. The prevalence of osteoporosis in men and women using estimated vFNBMD vs. aFNBMD cut-offs was 19 and 14.2 vs 11.8 and 26 percent, respectively. Prevalence increased with age. Estimated vFNBMD shows only small sex-correlated differences in bone density. Estimated vFNBMD was more sensitive than aFNBMD, when used to define the osteoporotic cut-offs in men, while it was less sensitive than aFNBMD in women.

Absorptiometry, Photon↗

PubMed2004

Incomplete renal tubular acidosis and bone mineral density: a population survey in an area of endemic renal tubular acidosis.

BACKGROUND: 'Primary' osteoporosis has been associated with a high incidence of a renal acidification defect, incomplete renal tubular acidosis (iRTA). An acid loading test, to exclude the defect, has been recommended for inclusion in the work-up of osteoporosis. However, there is no community-based study to confirm its utility. METHOD: A community-based survey was conducted in the Khon Kaen province, Thailand, between January and June, 2000. We randomly enrolled 361 apparently healthy adults, 146 men and 215 women, in this study. The bone mineral densities (BMDs) of the spine and femur were determined in all subjects. The diagnosis of iRTA was based on: normal serum electrolytes and one or both of first morning urinary pH >5.5 or the failure of an acid loading test to decrease it to >5.5. Dietary diaries, serum electrolyte tests and 24 h urine collections were obtained from all iRTA subjects. RESULTS: There were 23 (6.4%) iRTA subjects in the population studied. The age, height, weight and calcium intake were comparable between iRTA and normal subjects, as were the BMDs of spine and femur. There was no difference between the two groups in the distributions of BMD with age for either area. Multiple regression analyses of the studied population demonstrated that age, body weight, duration of menopause and gender (only for the femoral neck) were independent variables that affected BMD. CONCLUSION: Incomplete distal renal tubular acidosis alone was not associated with lower bone mass in this cohort. It may nevertheless be valuable to monitor serum electrolytes and BMD in patients with iRTA due to their tendency to develop intermittent metabolic acidosis.

Acidosis, Renal Tubular↗

PubMed2004

Alteration of noncollagenous bone matrix proteins in distal renal tubular acidosis.

Our previous report on bone histomorphometry in patients with distal renal tubular acidosis (dRTA) revealed decreased bone formation rate (BFR) when compared to healthy subjects. The abnormality improved significantly after alkaline therapy. The modest increase in osteoblastic surface, after correction of metabolic acidosis, could not explain the striking improvement in bone formation, suggesting additional influence of metabolic acidosis on osteoblast function and/or bone matrix mineralization. Osteoblasts and, to a lesser extent, osteoclasts synthesize and secrete bone matrix including type I collagen and various noncollagenous proteins (NCPs). Substantial evidence suggested diverse functions of NCPs related to bone formation, resorption, and mineralization. Metabolic acidosis, through its effect on bone cells, may result in an alteration in the production of NCPs. Our study examined bone histomorphometry with detailed analysis on the mineralization parameters and NCPs expression within the bone matrix of patients with dRTA before and after treatment with alkaline. Seven dRTA patients underwent bone biopsy at their initial diagnosis and again 12 months after alkaline therapy. Bone mineral density (BMD) and bone histomorphometry were obtained at baseline and after the treatment. The expression of NCPs was examined by immunohistochemistry, quantitated by digital image analysis, and reported as a percentage of area of positive staining or mineralized trabecular bone area. Alkaline therapy normalized the low serum phosphate and PTH during acidosis. The reduction in BMD at baseline improved significantly by the treatment. Bone histomorphometry demonstrated the increase in osteoid surface and volume without significant alteration after acidosis correction. In comparison to the normal subjects, osteoid thickness was slightly but insignificantly elevated. Osteoblast and osteoclast populations and their activities were suppressed. The reduction in mineral apposition rate and adjusted apposition rate were observed in conjunction with the prolongation of mineralization lag time. Alkaline therapy improved the mineralization parameters considerably. In addition to the increase in BFR relative osteoblast number after acidosis correction, osteocalcin expression in the bone matrix increased significantly from 16.7% to 22.3%. Six of seven patients had decreased osteopontin expression. In conclusion, the abnormal bone remodeling in dRTA is characterized by low turnover bone disease with some degree of defective mineralization. Alteration of NCPs expression suggested the effect of metabolic acidosis on bone cells. Alkaline therapy increased bone mass through the restoration of bone mineral balance and, perhaps, improved osteoblast function.

Acidosis, Renal Tubular↗

PubMed2004

Efficacy of intermittent low dose alendronate in Thai postmenopausal osteoporosis.

Alendronate has been proven to be effective in the prevention and treatment of postmenopausal osteoporosis with the recommended daily dose of 10 mg. However, a constraining requirement for dosing limited its general acceptance in treatment. Since alendronate is potent and has a long half-life, weekly administration of alendronate in lower total doses might be safer and more convenient. The purpose of this study was to determine the efficacy of low dose once-weekly 20 mg alendronate in Thai postmenopausal women with osteoporosis. Thirty-nine postmenopausal women with osteoporosis received alendronate 20 mg once a week plus 750 mg elemental calcium daily. Bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (DXA) at baseline and 6 and 12 months after treatment. Serum C-terminal telopeptide of type I collagen (CTx-I) was measured by electrochemiluminescence immunoassay at baseline and 3 months after treatment. By the end of 1 year, once weekly 20 mg alendronate significantly increased vertebral BMD (+6.2%, p < 0.001 vs baseline) from baseline whereas there was a reduction of 60.7% in serum CTx-I at 3 months. However, the BMD at femur did not increase significantly (+0.64%). Conclusion. Low-dose intermittent once-weekly 20 mg alendronate was effective, cost saving and had a good safety profile in increasing vertebral BMD and stabilizing BMD at the femoral neck in postmenopausal osteoporosis.

Absorptiometry, Photon↗

PubMed2004

Schedule of taking calcium supplement and the risk of nephrolithiasis.

BACKGROUND: Variation in the timing of calcium supplement may affect gastrointestinal absorption of both calcium and oxalate differently and may associate with variable risk of calcium oxalate nephrolithiasis. There are few human studies addressing specifically the appropriate time for taking calcium supplement. Therefore, this study was performed to compare calcium bioavailability and the risk of calcium oxalate stone formation for calcium supplement taken with meal vs. taken at bedtime. METHODS: Thirty-two healthy male navy privates, 22.7 +/- 1.9 years old (mean +/- SD), who had normal renal function (serum creatinine less than 150 umol/L) and no history of renal stone, participated in the study. The subjects were randomly allocated into two groups of 16 each. Group A took 1 g of calcium carbonate with meal, 3 times/day; and group B took 3 g/day of calcium carbonate at bedtime. After taking the regimens for 1 week, followed by 1 month of washout period, crossover between both groups was done. The diet was controlled throughout the study. Twenty-four-hour urine collections for the determination of urinary constituents were obtained at baseline and after taking both regimens of calcium supplement. Activity product for calcium oxalate was determined to assess the risk of calcium oxalate stone formation. RESULTS: Urinary excretions of calcium were significantly elevated above the baseline values when taking calcium supplement both with meal (3.48 +/- 2.13 mmol/day vs. 5.17 +/- 2.61 mmol/day, P < 0.05) and at bedtime (3.09 +/- 1.70 mmol/day vs. 5.08 +/- 2.34 mmol/day, P < 0.05). There was no difference between the two regimens in the urinary calcium excretions. The urinary oxalate was decreased significantly when the subjects took calcium supplement with meal compared with the corresponding baseline value (0.13 +/- 0.05 vs. 0.17 +/- 0.07 mmol/d, P= 0.01). In contrast, there was no alteration in urinary oxalate when calcium supplement was taken at bedtime compared to the baseline values (0.15 +/- 0.05 mmol/day vs. 0.15 +/- 0.06 mmol/day, P= 0.9). Compared with the corresponding baseline values, there was no significant increase in the activity product for calcium oxalate when taking calcium with meal (0.54 +/- 0.25 vs. 0.57 +/- 0.22, P= 0.54), but it was increased significantly when calcium supplement was taken at bedtime (0.47 +/- 0.21 vs. 0.72 +/- 0.27, P < 0.01). CONCLUSION: Calcium supplement should be taken with meal in order to avoid increasing the risk of calcium oxalate nephrolithiasis.

Adult↗