Prevalence of and risk factors for sarcopenia in community-dwelling people: The Vietnam Osteoporosis Study.

BACKGROUND: Sarcopenia is a geriatric disease characterized by the progressive and generalized loss of skeletal lean mass and strength with age. The prevalence of sarcopenia in the Vietnamese population is unknown. This study sought to estimate the prevalence of and risk factors for sarcopenia among community-dwelling individuals in Vietnam. METHODS: This cross-sectional study is part of the ongoing Vietnam Osteoporosis Study project. The study involved 1308 women and 591 men aged 50 years and older as at 2015 (study entry). Whole-body dual-energy X-ray absorptiometry was used to measure the appendicular skeletal lean mass. Anthropometric and clinical data were collected using a structured questionnaire. Sarcopenia was defined according to the criteria proposed by the Asian Working Group for Sarcopenia in 2019. Logistic regression analysis was used to determine the association between potential risk factors and sarcopenia. RESULTS: The prevalence of sarcopenia in women and men was 14% (n = 183) and 16% (n = 83), respectively. Age (odds ratio [OR] per 10 years = 1.37; 95% confidence interval [CI] 1.26-1.48) and being underweight (OR = 1.61; 95% CI 1.00-2.58) were independently associated with increased risk of sarcopenia. The combination of low physical activity, being underweight and advancing age accounted for ~27% of sarcopenic patients. However, most of the attributable fraction was due to ageing. CONCLUSIONS: Sarcopenia is common in community-dwelling Vietnamese adults, particularly those with advancing age, who are underweight and with low physical activity.

Burden of osteoporosis in Vietnam: An analysis of population risk.

PURPOSE: To estimate the proportion of men and women aged 50 years and older who would be classified as "high risk" for fracture and eligible for anti-fracture treatment. METHODS: The study involved 1421 women and 652 men aged 50 years and older, who were recruited from the general population in Ho Chi Minh City, Vietnam. Fracture history was ascertained from each individual. Bone mineral density (BMD) was measured at the lumbar spine and femoral neck by DXA (Hologic Horizon). The diagnosis of osteoporosis was based on the T-scores ≤ -2.50 derived from either femoral neck or lumbar spine BMD. The 10-year risks of major fractureand hip fracture were estimated from FRAX version for Thai population. The criteria for recommended treatment were based on the US National Osteoporosis Foundation (NOF). RESULTS: The average age of women and men was ~60 yr (SD 7.8). Approximately 11% (n = 152) of women and 14% (n = 92) of men had a prior fracture. The prevalence of osteoporosis was 27% (n = 381; 95% CI, 25 to 29%) in women and 13% (n = 87; 95% CI, 11 to 16%) in men. Only 1% (n = 11) of women and 0.1% (n = 1) of men had 10-year risk of major fracture ≥ 20%. However, 23% (n = 327) of women and 9.5% (n = 62) of men had 10-year risk of hip fracture ≥ 3%. Using the NOF recommended criteria, 49% (n = 702; 95% CI, 47 to 52%) of women and 35% (n = 228; 95% CI, 31 to 39%) of men would be eligible for therapy. CONCLUSION: Almost half of women and just over one-third of men aged 50 years and older in Vietnam meet the NOF criteria for osteoporosis treatment. This finding can help develop guidelines for osteoporosis treatment in Vietnam.

Development of a model for identification of individuals with high risk of osteoporosis.

Many developing countries, including Vietnam, lack DXA resources for the diagnosis of osteoporosis, which poses difficulties in the treatment and prevention of osteoporosis at the individual level. We have developed and validated a prediction model for individualized assessment of osteoporosis based on age and body weight for men and women. PURPOSE: To estimate the prevalence of osteoporosis and to develop and validate a prediction model for estimating the absolute risk of osteoporosis in the Vietnamese population. METHODS: The study involved 1477 women and 669 men aged 50 years and older, who were recruited from the general population in Ho Chi Minh City (Vietnam). Bone mineral density (BMD) at the femoral neck, total hip, and lumbar spine was measured by DXA (Hologic Horizon). The diagnosis of osteoporosis was based on BMD T-score (T-score ≤ - 2.5) at the femoral neck or lumbar spine which was derived from a published reference range for the Vietnamese population. The logistic regression model was used to develop the prediction model for men and women separately. The bootstrap method was used to evaluate the model performance using 3 indices: the area under the receiver's operating characteristic curve (AUC), Brier score, and R-squared values. RESULTS: The prevalence of osteoporosis at any site was 28.3% in women and 15.5% in men. The best predictors of osteoporosis risk were age and body weight. Using these indices, a cut-off of 0.195 for women yielded an AUC of 0.825, Brier score = 0.112, and it explained 33.8% of total variance in risk of osteoporosis between individuals. Similarly, in men, the internal validation with a cut-off of 0.09 yielded good accuracy, with AUC = 0.858, Brier score = 0.040, and R-squared = 30.3%. CONCLUSION: We have developed and validated a prediction model for individualized assessment of osteoporosis. In settings without DXA, this model can serve as a useful screening tool to identify high-risk individuals for DXA scan.

Sex-difference in bone architecture and bone fragility in Vietnamese.

This study sought to define the sex-difference in trabecular and cortical bone parameters in Vietnamese individuals. The study involved 1404 women and 864 men aged between 20 and 86 years who were recruited from Ho Chi Minh City, Vietnam. Trabecular and cortical volumetric BMD were measured at the proximal tibia and proximal radius at 4%, 38%, and 66% points, using a peripheral quantitative computed tomography XCT2000 (Stratec, Germany). Polar strength strain index was estimated from cortical bone parameters. Changes in bone parameters were assessed by the multiple linear regression model. Among individuals aged 20-39 years, women had significantly lower peak trabecular BMD at both the radius (40%) and tibia (16%) than men, but the age-related reduction in trabecular BMD were similar between two sexes. For cortical BMD, peak values in women and men were comparable, but the age-related diminution was greater in women than men. At any age, polar strength strain index in women was lower than men, and the difference was mainly attributable to cortical bone area and total bone mass. We conclude that in the elderly, sex-related difference in trabecular BMD is originated during growth, but sex-related difference in cortical BMD is determined by differential age-related bone loss.

Genetic determinant of trabecular bone score (TBS) and bone mineral density: A bivariate analysis.

This study sought to estimate the extent of genetic influence on the variation in trabecular bone score (TBS). We found that genetic factors accounted for ~45% of variance in TBS, and that the co-variation between TBS and bone density is partially determined by genetic factors. INTRODUCTION: Trabecular bone score has emerged as an important predictor of fragility fracture, but factors underlying the individual differences in TBS have not been explored. In this study, we sought to determine the genetic contribution to the variation of TBS in the general population. METHODS: The study included 556 women and 189 men from 265 families. The individuals aged 53years (SD 11). We measured lumbar spine bone mineral density (BMD; Hologic Horizon) and then derived the TBS from the same Hologic scan where BMD was derived. A biometric model was applied to the data to partition the variance of TBS into two components: one due to additive genetic factors, and one due to environmental factors. The index of heritability was estimated as the ratio of genetic variance to total variance of a trait. Bivariate genetic analysis was conducted to estimate the genetic correlation between TBS and BMD measurements. RESULTS: TBS was strongly correlated with lumbar spine BMD (r=0.73; P<0.001). On average TBS in men was higher than women, after adjusting age and height which are significantly associated with both TBS and lumbar spine BMD. The age and height adjusted index of heritability of TBS was 0.46 (95% CI, 0.39-0.54), which was not much different from that of LSBMD (0.44; 95% CI, 0.31-0.55). Moreover, the genetic correlation between TBS and LSBMD was 0.35 (95% CI, 0.21-0.46), between TBS and femoral neck BMD was 0.21 (95% CI, 0.10-0.33). CONCLUSIONS: Approximately 45% of the variance in TBS is under genetic influence, and this effect magnitude is similar to that of lumbar spine BMD. This finding provides a scientific justification for the search for specific genetic variants that may be associated with TBS and fracture risk.

Body Composition in Individuals with Asymptomatic Osteoarthritis of the Knee.

Greater body mass index (BMI) is associated with a greater risk of osteoarthritis (OA). This study sought to investigate whether the association is mediated by fat mass or lean mass. The study involved 170 men and 488 women aged between 20 and 90 (average age: 55) who were randomly recruited from Ho Chi Minh City, Vietnam. The presence of knee OA was radiographically diagnosed based on the Kellgren-Lawrence criteria. Lean mass (LM) and fat mass (FM) were obtained from the DXA whole body scan (Hologic QDR-4500). The relationship between OA, LM, and FM was analyzed by a series of multiple linear regression models which take into account the effects of gender and age. As expected, men and women with knee OA were older than those without OA (65 vs 51 year in men, and 64 vs 52 year in women). After adjusting for age, OA was associated with greater FM and percent body fat (PBF), but the association was only observed in women, not in men. There was no statistically significant difference in LM between OA and non-OA individuals. Moreover, after adjusting for age and BMI or PBF, bone density in OA patients was not significantly different from non-OA individuals. Women with OA of the knee have greater fat mass than non-OA individuals, and that there is no significant difference in bone density between OA and non-OA individuals. Thus, the association between body mass index and OA is mainly mediated by fat mass.

Prevalence and pattern of radiographic intervertebral disc degeneration in Vietnamese: a population-based study.

Intervertebral disc degeneration (IDD) is one of the most common skeletal disorders, yet few data are available in Asian populations. We sought to assess the prevalence and pattern of radiographic IDD in a Vietnamese population. This population-based cross-sectional investigation involved 170 men and 488 women aged ≥40 years, who were randomly sampled from the Ho Chi Minh City (Vietnam). Anthropometric data, clinical history and self-reported back and neck pain were ascertained by a questionnaire. Plain radiographs (from the cervical spine, thoracic spine to the lumbar spine) were examined for the presence of disc space narrowing and/or osteophytosis using the Kellgren-Lawrence (KL) grading system. The presence of radiographic IDD was defined if the KL grade was 2 or greater in at least one disc. The prevalence of radiographic IDD was 62.4% (n = 106) in men and 54.7% (n = 267) in women. The most frequently affected site was the lumbar spine with prevalence being 50.6 and 43.2% in men and women, respectively. The prevalence of IDD increased with advancing age: 18.8% among those aged 40-49 years, and increased to 83.4% in those aged ≥60 years. Self-reported neck pain and lower back pain were found in 30 and 44% of individuals, respectively. There was no statistically significant association between self-reported neck pain and cervical spine OA. These data suggest that radiographic IDD is highly prevalent in the Vietnamese population, and that self-reported back pain is not a sensitive indicator of IDD.

Prevalence of radiographic osteoarthritis of the knee and its relationship to self-reported pain.

BACKGROUND AND AIM: Osteoarthritis (OA) of the knee is one of the most common skeletal disorders, yet little data are available in Asian populations. We sought to assess the prevalence and pattern of radiographic OA of the knee, and its relationship to self-reported pain in a Vietnamese population. METHODS: The study was based on a sample of 170 men and 488 women aged ≥40 years who were randomly sampled from the Ho Chi Minh City (Vietnam). Radiographs of the knee were graded from 0 to 4 according to the Kellgren and Lawrence scale. Osteoarthritis was defined as being present in a knee if radiographic grades of 2 or higher were detected. Knee pain and symptoms were ascertained by direct interview using a structured questionnaire. RESULTS: The point prevalence of radiographic OA of the knee was 34.2%, with women having higher rate than men (35.3% vs 31.2%). The prevalence of knee OA increased with advancing age: 8% among those aged 40-49 years, 30% in those aged 50-59 years, and 61.1% in those aged ≥60 years. Greater BMI was associated with higher risk of knee OA. Self-reported knee pain was found in 35% of men and 62% of women. There was a statistically significant association between self-reported knee pain and knee OA (prevalence ratio 3.1; 95% CI 2.0 to 4.6). CONCLUSIONS: These data indicate that approximately a third of Vietnamese men and women have radiographic OA in the knee, and that self-reported knee pain may be used as an indicator of knee osteoarthritis.