The Vietnam Osteoporosis Study: Rationale and design.

ObjectivesOsteoporosis and fracture impose a significant health care burden on the contemporary populations in developing countries. The Vietnam Osteoporosis Study (VOS) sought to assess the burden of osteoporosis and its comorbidities in men and women.MethodsThe study was designed as a population-based family investigation in which families were randomly recruited from Ho Chi Minh City, Vietnam. Individuals were assessed for bone health, including bone mineral density (BMD) and body composition and trabecular and cortical bone properties by pQCT (peripheral quantitative computed tomography). Fasting blood samples were obtained for the analysis of plasma glucose, glycosylated hemoglobin, and bone turnover markers. Genomic DNA extraction from whole blood samples for further genetic and genomic analyses.ResultsWe have recruited more than 4157 individuals from 817 families. The average age of participants was 51, with approximately 45% of the individuals aged 50 years and older. Approximately 3% of participants were obese (body mass index ≥ 30 kg/m2), and 21% were overweight. Notably, 11% of participants aged 40 years and older were diabetic. Among those aged 50 years and older, approximately 14% of women and 5% of men had osteoporosis (i.e., femoral neck BMD T-scores ≤ -2.5). There were modest correlations between volumetric BMD and areal BMD.ConclusionsVOS is a major bone research project in Vietnam aimed at comprehensively documenting the burden osteoporosis, its co-occurrence of chronic diseases, and their underlying etiologies. The Study will make important contributions to the literature of bone health worldwide

Lean mass and peak bone mineral density.

ObjectivesThe association between body composition parameters and peak bone mineral density is not well documented. The aim of this study is to assess the relative contributions of lean mass and fat mass on peak bone mineral density (BMD).MethodsThe study involved 416 women and 334 men aged between 20 and 30 years who were participants in the population-based Vietnam Osteoporosis Study. Whole body composition parameters (eg, fat mass and lean mass) and BMD at the lumbar spine and femoral neck were measured by dual-energy X-ray absorptiometry. The association between lean mass and fat mass and BMD was analyzed by the linear regression model using the Least Absolute Shrinkage and Selection Operator (LASSO).ResultsPeak BMD in men was higher than women, and the difference was more pronounced at the femoral neck (average difference: 0.123 g/cm2; 95% confidence interval [CI] 0.105-0.141 g/cm2) than at the lumbar spine (average difference 0.019 g/cm2; 95% CI, 0.005-0.036 g/cm2). Results of LASSO regression indicated that lean mass was the only predictor of BMD for either men or women. Each kilogram increase in lean mass was associated with ∼0.01 g/cm2 increase in BMD. Lean mass alone explained 16% and 36% of variation in lumbar spine and femoral neck BMD, respectively.ConclusionsLean mass, not fat mass, is the main determinant of peak bone mineral density. This finding implies that good physical activity during adulthood can contribute to the maximization of peak bone mass during adulthood

Association between carotid intima-media thickness and bone mineral density: A cross-sectional study in Vietnamese men and women aged 50 years and older

© 2019 Author(s). Objectives The association between osteoporosis and atherosclerosis remains controversial. We sought to define the relationship between carotid intima-media thickness and bone mineral density (BMD) in individuals of Vietnamese background. Design and setting Cross-sectional study in Ho Chi Minh City, Vietnam. Participants The study involved 1460 individuals (559 men) aged 50 years and older (average age 59 years) who were randomly recruited from the community. Outcome measures BMD at the femoral neck and lumbar spine was measured by dual-energy X-ray absorptiometry (Hologic, Waltham, Massachusetts, USA). Carotid intima-media thickness (cIMT) was measured using a Philips Ultrasonography (HD7XE). The presence of atherosclerotic plaque was ascertained for each individual. The association between cIMT and BMD was analysed by a multiple linear regression model. Results In unadjusted analysis, cIMT was positively associated with femoral neck BMD in men (p=0.005), but not in women (p=0.242). After adjusting for age, smoking, diabetes and hypertension, the association remained statistically significant in men (partial R 2 =0.005; p=0.015) but not in women (partial R 2 =0.008; p=0.369). When the analysis was limited to individuals aged 60 years and older, the association between cIMT and BMD was no longer statistically significant. There was no statistically significant association between cIMT and lumbar spine BMD in either men or women. Conclusions In Vietnamese individuals aged 50 years and older, there is a clinically non-significant but statistically significant association between carotid intima-media thickness and BMD in men, not in women

Quantification of the relative contribution of estrogen to bone mineral density in men and women

Background: The study quantified the relative contributions of estrogen (E2) and total testosterone (TT) to variation in bone mineral density in men and women. Methods. This was a cross-sectional study which involved 200 men and 415 women aged 18 to 89 years. BMD at the lumbar spine (LS) and femoral neck (FN) was measured by DXA. Serum levels of E2 and TT were measured by electrochemiluminescence immunoassays. The association between E2, TT, and BMD was analyzed by the multiple linear regression model, adjusting for age and BMI. The contribution of each hormone to the variation in BMD was quantified by the bootstrap method. Results: In women, higher serum levels of E2, but not TT, were significantly associated with greater BMD at the FN (P = 0.001) and LS (P < 0.0001). In men, higher serum levels of E2 were independently associated with greater FNBMD (P = 0.008) and LSBMD (P = 0.086). In the multiple linear regression model, age, body weight and E2 accounted for 50-55% variance in FNBMD, and 25% (in men) and 48% (in women) variance in LSBMD. Variation in E2 accounted for 2.5% (95% CI 0.4 - 7.8%) and 11.3% (95% CI 8.1 - 15.3%) variation in FNBMD in men and women, respectively. Moreover, E2 contributed 1.2% (95% CI 0.1 - 5.8%) and 11.7% (95% CI 8.5 - 15.9%) variation in LSBMD in men and women, respectively. Conclusions: Estrogen is more important than testosterone in the determination of age-related bone mineral density men and women of Vietnamese background. However, the relative contributions of estrogen to bone mineral density in men are likely modest. © 2013 Ho-Pham et al.; licensee BioMed Central Ltd

Discordance in the diagnosis of diabetes: Comparison between HbA1c and fasting plasma glucose

© 2017 Ho-Pham et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Objective HbA1c has been introduced as a complementary diagnostic test for diabetes, but its impact on disease prevalence is unknown. This study evaluated the concordance between HbA1c and fasting plasma glucose (FPG) in the diagnosis of diabetes in the general population. Materials and methods The study was designed as a population based investigation, with participants being sampled from the Ho Chi Minh City, Vietnam. Blood samples were collected after overnight fasting and analyzed within 4 hours after collection. HbA1c was measured with high pressure liquid chromatography (Arkray Adams, Japan). FPG was measured by the hexokinase method (Advia Autoanalyzer; Bayer Diagnostics, Germany). Diabetes was defined as HbA1c 6.5% or FPG 7.0 mmol/L. Prediabetes was classified as HbA1c between 5.7% and 6.4%. Results The study included 3523 individuals (2356 women) aged 30 years and above. Based on the HbA1c test, the prevalence of diabetes and prediabetes was 9.7% (95%CI, 8.7–10.7%; n = 342) and 34.6% (33.0–36.2; n = 1219), respectively. Based on the FPG test, the prevalence of diabetes and prediabetes was 6.3% (95%CI, 5.5–7.2%; n = 223) and 12.1% (11.1–13.2; n = 427). Among the 427 individuals identified by FPG as "pre-diabetes", 28.6% were classified as diabetes by HbA1c test. The weighted kappa statistic of concordance between HbA1c and FPG was 0.55, with most of the discordance being in the prediabetes group. Conclusion These data indicate that there is a significant discordance in the diagnosis of diabetes between FPG and HbA1c measurements, and the discordance could have significant impact on clinical practice. FPG appears to underestimate the burden of undiagnosed diabetes

Relationship between body mass index and percent body fat in Vietnamese: Implications for the diagnosis of obesity

© 2015 Ho-Pham et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Background The burden of obesity in Vietnam has not been well defined because there is a lack of reference data for percent body fat (PBF) in Asians. This study sought to define the relationship between PBF and body mass index (BMI) in the Vietnamese population. Methods The study was designed as a comparative cross-sectional investigation that involved 1217 individuals of Vietnamese background (862 women) aged 20 years and older (average age 7 yr) who were randomly selected from the general population in Ho Chi Minh City. Lean mass (LM) and fat mass (FM) were measured by DXA (Hologic QDR 4500). PBF was derived as FM over body weight. Results Based on BMI 30, the prevalence of obesity was 1.1% and 1.3% for men and women, respectively. The prevalence of overweight and obesity combined (BMI 25) was ∼ 24% and ∼ 19% in men and women, respectively. Based on the quadratic relationship between BMI and PBF, the approximate PBF corresponding to the BMI threshold of 30 (obese) was 30.5 in men and 41 in women. Using the criteria of PBF >30 in men and PBF >40 in women, approximately 15% of men and women were considered obese. Conclusion These data suggest that body mass index underestimates the prevalence of obesity. We suggest that a PBF >30 in men or PBF >40 in women is used as criteria for the diagnosis of obesity in Vietnamese adults. Using these criteria, 15% of Vietnamese adults in Ho Chi Minh City was considered obese

Trends in incidence and histological pattern of thyroid cancer in Ho Chi Minh City, Vietnam (1996–2015): a population-based study

Background The burden and trend of thyroid cancer in Vietnam have not been well documented. This study aimed to investigate the trends in incidence and histological pattern of thyroid cancer in Ho Chi Minh City from 1996 to 2015. Methods A population-based study retrieved data from the Ho Chi Minh City Cancer Registry during 1996–2015. Trends in the incidence of thyroid cancer were investigated based on age, gender, and histology for each 5-year period. Annual percentage change (APC) in incidence rates was estimated using Joinpoint regression analysis. Results In the study period, there were 5953 thyroid cancer cases (men-to-women ratio 1:4.5) newly diagnosed in Ho Chi Minh City with the mean age of 42.9 years (±14.9 years). The age-standardized incidence rate of thyroid cancer increased from 2.4 per 100,000 during 1996–2000 (95% confidence interval [95% CI]: 2.2–2.6) to 7.5 per 100,000 during 2011–2015 (95% CI: 7.3–7.9), corresponded to an overall APC of 8.7 (95% CI 7.6–9.9). The APC in men and women was 6.2 (95% CI: 4.2–8.2) and 9.2 (95% CI: 8.0–10.4), respectively. The incidence rate in the < 45 years age group was the highest diagnosed overall and increased significantly in both men (APC 11.0) and women (APC 10.1). Both genders shared similar distribution of subtype incidences, with papillary thyroid cancer constituted the most diagnosed (73.3% in men and 85.2% in women). The papillary thyroid cancer observed a markedly increase overall (APC of 10.7 (95% CI 9.3–12.0)). Conclusions There were appreciable increases in the age-standardized incidence rate of thyroid cancer in both genders, mainly contributed by the papillary subtype. The age of patients at diagnosis decreased gradually. The widespread utilization of advanced diagnostic techniques and healthcare accessibility improvement might play a potential role in these trends. Further investigations are needed to comprehend the risk factors and trends fully

Development and validation of a prognostic model for predicting 30-day mortality risk in medical patients in emergency department (ED)

© 2017 The Author(s). The primary aim of this prospective study is to develop and validate a new prognostic model for predicting the risk of mortality in Emergency Department (ED) patients. The study involved 1765 patients in the development cohort and 1728 in the validation cohort. The main outcome was mortality up to 30 days after admission. Potential risk factors included clinical characteristics, vital signs, and routine haematological and biochemistry tests. The Bayesian Model Averaging method within the Cox's regression model was used to identify independent risk factors for mortality. In the development cohort, the incidence of 30-day mortality was 9.8%, and the following factors were associated with a greater risk of mortality: male gender, increased respiratory rate and serum urea, decreased peripheral oxygen saturation and serum albumin, lower Glasgow Coma Score, and admission to intensive care unit. The area under the receiver operating characteristic curve for the model with the listed factors was 0.871 (95% CI, 0.844-0.898) in the development cohort and 0.783 (95% CI, 0.743-0.823) in the validation cohort. Calibration analysis found a close agreement between predicted and observed mortality risk. We conclude that the risk of mortality among ED patients could be accurately predicted by using common clinical signs and biochemical tests