Visual functioning and quality of life among the older people in Hong Kong.

OBJECTIVES: This study aimed to examine the association of visual functioning and health-related quality of life (HRQOL) among the older community in Hong Kong. DESIGN: This study used the baseline examination of a cohort study MrOs and MsOs (a large study for osteoporosis in men and women). SETTING: This study was set in the Hong Kong community. PARTICIPANTS: A total of 4000 ambulatory community-dwelling Chinese men and women aged 65 years or above participated in this study. MEASUREMENTS: Health-related quality of life was assessed by Medical Outcomes Study Short Form-12 (SF-12), with physical component summary (PCS) and mental component summary (MCS) scores. Demographics, medical history, mental status, and quality of life were obtained from face-to-face interviews, using standard structured questionnaire. Visual functions (i.e., binocular visual acuity, contrast sensitivity, and stereopsis) were assessed by different visual tests after refraction corrections. Different visual functions were tested simultaneously in multiple ordinal logistic regression models. RESULTS: Better binocular visual acuity, contrast sensitivity, and stereopsis were associated with higher PCS. Visual acuity and contrast sensitivity was associated with PCS after adjustment of different visual functions and sex, age, education level, cognitive status, and history of diabetes in multivariate analysis, (OR = 0.73, 95% CI = 0.54 0.98) for low vision (≤6/24) compared with ≥6/9 in visual acuity and (OR = 1.34, 95% CI = 1.09 1.64) for contrast sensitivity row b 5-8 (best) compared with 0-1 (worst). MCS was only associated with visual acuity and contrast sensitivity, but no association was found after adjustment. CONCLUSION: Apparent association was found between visual functions and HRQOL among older community in Hong Kong. In addition to visual acuity, contrast sensitivity is also important, so eye care should also cover.

Vitamin D receptor 3' haplotypes are unequally expressed in primary human bone cells and associated with increased fracture risk: the MrOS Study in Sweden and Hong Kong.

UNLABELLED: The VDR is a prime candidate gene for osteoporosis. Here, we studied three common VDR haplotypes in relation to bone phenotypes in 5014 participants of the global MrOS Study. We also studied the relative expression of the haplotypes in human bone cells. One haplotype was associated with increased fracture risk and differently expressed in primary human bone cells. INTRODUCTION: Vitamin D plays an essential role in skeletal metabolism by binding to its nuclear steroid receptor, the vitamin D receptor (VDR). The heritability of BMD is well established, and the VDR gene is considered a prime candidate suggested to partially account for genetically controlled BMD variance in the population. MATERIALS AND METHODS: Here, we reconstructed common haplotypes in the VDR 3' untranslated region (UTR) and studied the association to BMD and risk of vertebral fractures in elderly men from Sweden (n = 3014) and Hong Kong (n = 2000), all participants of the global MrOS Study. To assess any functional implications of the VDR polymorphisms, we studied allele-specific expressions of the different VDR 3' UTR haplotypes in the normal chromosomal context of 70 unrelated human trabecular bone samples. This was performed by quantitative genotyping of coding polymorphisms in RNA samples and in corresponding DNA samples isolated from the bone samples. RESULTS: Three major haplotypes were reconstructed and in agreement with the previously well-defined baT, BAt, and bAT haplotypes, herein denoted Hap1, Hap2, and Hap3. The Hap1 haplotype was independently associated with increased risk of vertebral fractures in Swedish men (OR, 1.655; 95% CI, 1.146-2.391; p < 0.01) and with lower lumbar spine BMD in elderly men from Sweden (p < 0.01) and Hong Kong (p < 0.05). The VDR gene was also shown to exhibit a 3' UTR haplotype dependent allelic imbalance, indicating that the VDR Hap1 allele was overexpressed in human trabecular bone samples. CONCLUSIONS: The results indicate that the relatively overexpressed VDR Hap1 haplotype could be considered a risk allele for osteoporosis regardless of ethnicity.

Associated factors and health impact of sarcopenia in older chinese men and women: a cross-sectional study.

BACKGROUND: Sarcopenia is increasingly being recognized as a feature of frailty in old age and is associated with unfavorable health outcomes in Western populations. Little is known about sarcopenia among Asian elderly populations. OBJECTIVES: The study was undertaken to study the association between sarcopenia and common chronic illnesses, lifestyle factors, psychosocial well-being and physical performance. METHODS: 4,000 community-dwelling Chinese elderly >/=65 years were recruited. Medical illnesses, cigarette smoking, alcohol consumption, physical activity level and psychosocial well-being scores were recorded. Physical performance measured included grip strength, timed chair-stands, stride length and a timed 6-meter walk. Muscle mass was measured using dual-energy X-ray absorptiometry. Relationships between appendicular skeletal muscle mass (ASM/ht(2)) and multiple variables were analyzed using uni- and multivariate analyses. RESULTS: Mean ASM/ht(2) was 7.19 and 6.05 kg/m(2) in men and women respectively. Older age, cigarette smoking, chronic lung disease, atherosclerosis, underweight, and physical inactivity were associated with low adjusted ASM, which was in turn associated with poorer physical well-being in men. After adjustment to age, lower appendicular muscle mass was associated with weaker grip strength in both sexes. In men, lower limb tests (chair-stands, walking speed and step length) were not related to ASM, while in women, lower muscle mass was not associated with poorer lower limb muscle performance. CONCLUSIONS: Sarcopenia in community-dwelling older Chinese men and women was associated with cigarette smoking, chronic illnesses, underweight, physical inactivity, poorer well-being and upper limb physical performance.

Prevalence of and risk factors for sarcopenia in elderly Chinese men and women.

BACKGROUND: Several studies have documented the substantial health and economic burdens associated with sarcopenia among the elderly, but there has been no systematic study among Asians. A cross-sectional survey of elderly community-dwelling Chinese volunteers (262 men and 265 women), aged 70 years and older, was undertaken in Hong Kong. The purposes of this study were to evaluate the prevalence of and risk factors for sarcopenia in elderly Chinese, and to compare these observations with those in white persons. METHODS: Muscle mass was estimated by dual-energy X-ray absorptiometry. In this study, sarcopenia was defined as a total adjusted skeletal muscle mass two standard deviations or more below the normal mean for young Asian men and women in this study. The relationship between risk factors (alcohol consumption, cigarette smoking, regular exercise, body mass index, medical conditions) and sarcopenia was studied by multiple logistic regression. RESULTS: The prevalence of sarcopenia was 12.3% in Chinese men and 7.6% in Chinese women aged 70 years and older, which was slightly lower than figures observed in white persons. Being underweight was a significant risk factor in both men (odds ratio, 39.1; 95% confidence interval, 11.3 to 134.6) and women (odds ratio, 9.7; 95% confidence interval, 2.8 to 33.8). No other risk factors were found in Chinese men or women. CONCLUSIONS: Sarcopenia exists among elderly Chinese men and women, albeit at a lower rate than in white persons. This may be due to the lower muscle mass among young men and women or to an attenuated rate of loss in muscle mass with aging in the Chinese elderly. Being underweight is a major risk factor for sarcopenia in both sexes.

Effects of strength training on body composition and bone mineral content in children who are obese.

The purpose of this study was to test the hypothesis that strength training benefits diet-controlled obese children with respect to lean mass and bone mineral acquisition. Eighty-two Hong Kong school children (aged 10.4 +/- 1.0 years, 70 in Tanner stage 1, 12 in stage 2) who were obese/overweight were randomly assigned to receive either a balanced low-energy (900-1200 cal) diet plus strength training (n = 41) (training group) or the diet alone (n = 41) (control group). The training group attended a 75-minute strength exercise program 3 times/week for 6 weeks (phase 1), after which they were offered and 22 children opted to continue a once-weekly program for a further 28 weeks (phase 2). All children were evaluated at baseline, after 6 weeks, and at the end of the 36-week study (including an intervening 2-week introduction to phase 2). Body composition and bone mineral content were measured by dual-energy X-ray absorptiometry, and diet was assessed by food-frequency questionnaire. The results showed that the exercise programs were well accepted, with good attendance at the exercise classes. After 6 weeks, the children in the training group showed significantly larger increases in lean body mass (+ 0.8 kg [2.4%] vs. +0.3 kg [1.0%], p < 0.05) and total bone mineral content (+46.9 g [3.9%] vs. +33.6 g [2.9%], p < 0.05) than those in the control group. At the end of the study, these trends were maintained in the continued-training subgroup, though no longer reaching statistical significance. We conclude that in diet-controlled prepubertal obese/overweight children, participation in an exercise program with emphasis on strength training resulted in improved lean mass and bone mineral accrual.

Depression and bone mineral density: is there a relationship in elderly Asian men? Results from Mr. Os (Hong Kong).

Previous epidemiological study has suggested that depression might be associated with low bone mass in Caucasian women. This has not been studied in Asian men. Mr. Os (Hong Kong) is the first, large, cohort study on osteoporosis in Asian men, and the current analysis deals with the association between depression and bone mass in this group. Data from the baseline examination of Mr. Os (Hong Kong) were used. Two thousand Hong Kong men aged 65 to 92 years were recruited from the community. Depression was diagnosed by face-to-face interview, using a validated Chinese version of the Geriatric Depression Scale (GDS), with depression being defined as a cut-off score of 8 or more. Bone mineral density (BMD) of the lumbar spine, total hip and total body was measured by dual X-ray densitometry (DEXA) using the Hologic QDR-4500 W densitometer. Multiple regression was used to compare BMD in depressed and non-depressed subjects, controlling for confounding variables. In the study sample 8.5% of men were found to be depressed, and the BMD at the total hip in these subjects was 2.1% lower than in non-depressed subjects (95% CI -0.13 to -4.1), after adjustment for age, body weight, medical history, alcohol consumption, cigarette smoking, calcium intake, physical activity and antidepressant use. Depression was associated with a 1.4-fold (95% CI 1.00 to 2.08) relative risk (RR) of being diagnosed with a T-score equal to or less than -1.0 (low bone mass). We conclude that depression is associated with lower BMD; however, to determine whether depression causes lower BMD or vice versa, we will need to await findings from future prospective studies.

Vertebral bone mineral density, marrow perfusion, and fat content in healthy men and men with osteoporosis: dynamic contrast-enhanced MR imaging and MR spectroscopy.

PURPOSE: To prospectively use hydrogen 1 (1H) magnetic resonance (MR) spectroscopy and dynamic contrast material-enhanced MR imaging to measure vertebral body marrow fat content and bone marrow perfusion in older men with varying bone mineral densities as documented with dual x-ray absorptiometry (DXA). MATERIALS AND METHODS: This study had institutional review board approval, and all participants provided informed consent. DXA, 1H MR spectroscopy, and dynamic contrast-enhanced MR imaging of the lumbar spine were performed in 90 men (mean age, 73 years; range, 67-101 years). Vertebral marrow fat content and perfusion (maximum enhancement and enhancement slope) were compared for subject groups with differing bone densities (normal, osteopenic, and osteoporotic). The t test was used for comparisons between groups, and the Pearson test was used to determine correlation between marrow fat content and perfusion indexes. RESULTS: Eight subjects were excluded, yielding a final cohort of 82 subjects (mean age, 73 years; range, 67-101 years) that included 42 subjects with normal bone density (mean T score, 0.8 +/- 1.1 [standard deviation]), 23 subjects with osteopenia (mean T score, -1.6 +/- 0.4), and 17 subjects with osteoporosis (mean T score, -3.2 +/- 0.5). Vertebral marrow fat content was significantly increased in subjects with osteoporosis (mean fat content, 58.23% +/- 7.8) (P = .002) or osteopenia (mean fat content, 55.68% +/- 10.2) (P = .034) compared with that in subjects with normal bone density (50.45% +/- 8.7). Vertebral marrow perfusion indexes were significantly decreased in osteoporotic subjects (mean enhancement slope, 0.78%/sec +/- 0.3) compared with those in osteopenic subjects (mean enhancement slope, 1.15%/sec +/- 0.6) (P = .007) and those in subjects with normal bone density (mean enhancement slope, 1.48%/sec +/- 0.7) (P < .001). CONCLUSION: Subjects with osteoporosis have decreased vertebral marrow perfusion and increased marrow fat compared with these parameters in subjects with osteopenia. Similarly, subjects with osteopenia have decreased vertebral marrow perfusion and increased marrow fat compared with these parameters in subjects with normal bone density.

Factors associated with the lumbar spine and proximal femur bone mineral density in older men.

Bone mass is a major determinant of fracture, but there have been few comprehensive studies of the correlates of bone mineral density (BMD) in older men. The objective of the current cross-sectional analysis was to determine the factors associated with BMD of the lumbar spine and proximal femur in a large population-based sample of older men enrolled in The Osteoporotic Fractures in Men Study, "Mr.OS." We enrolled 5,995 men 65 years of age or older, 89% Caucasian, in Mr.OS at six US clinical centers. Demographic, medical and family history and lifestyle information was obtained by interview and physical function and anthropometric data by examination. Spine and hip BMD was measured using dual-energy X-ray absorptimetry. The multivariable linear regression models predicted 19 and 10% of the overall variance in BMD of the femoral neck and spine, respectively. African-American men had 6 to 11% higher BMD than Caucasian men independent of multiple factors. Hip BMD declined with advancing age, while spine BMD increased. Body weight (per 10 kg) and self report of diabetes were each associated with 2 to 4% higher BMD, while history of a non-trauma fracture and current use of selective serotonin reuptake inhibitors, but not other antidepressants, were associated with at least 4% lower BMD. Both maternal and paternal histories of fracture were associated with 1.4-1.7% lower BMD. Osteoarthritis, physical activity, grip strength, alcohol intake, and dietary calcium were positively related to BMD, while a history of chronic lung disease, prostate cancer, and kidney stones was associated with lower BMD. Smoking, caffeine intake, and thiazide diuretics were not related to BMD in older men. A number of lifestyle and behavioral characteristics and medical conditions were associated with BMD in older men. Identification of these correlates could improve methods to identify men at risk for fracture and improve our understanding of fracture etiology.

Exercise interventions: defusing the world's osteoporosis time bomb.

Osteoporosis is a major public health problem, affecting millions of people worldwide. The associated health care costs are growing in parallel with increases in elderly populations, and it is expected that the number of osteoporotic fractures will double over the next 50 years. The best way to address osteoporosis is prevention. Some interventions to maximize and preserve bone mass have multiple health benefits and are cost-effective. For example, modifications to diet and lifestyle can help to prevent osteoporosis, and could potentially lead to a significant decrease in fracture rates; and exercise is a valuable adjunct to programmes aimed at alleviating the risks and symptoms of osteoporosis. Practising exercise at a young age helps maximize the mineral density of bones while they are still growing and maturing, and continuing to excercise minimizes bone loss later in life. Not only does exercise improve bone health, it also increases muscle strength, coordination, balance, flexibility and leads to better overall health. Walking, aerobic exercise, and t'ai chi are the best forms of exercise to stimulate bone formation and strengthen the muscles that help support bones. Encouraging physical activity at all ages is therefore a top priority to prevent osteoporosis.

Bone marrow diffusion in osteoporosis: evaluation with quantitative MR diffusion imaging.

PURPOSE: To determine the diffusion of vertebral body marrow with quantitative MR diffusion imaging and to examine whether differences exist between subjects with postmenopausal osteoporosis and premenopausal control subjects. MATERIALS AND METHODS: A total of 44 consecutive women (mean age, 70 years) with documented bone mineral density (BMD) measured by dual energy x-ray absorptiometry (T-score) and 20 normal subjects (mean age, 28 years) were examined with echo-planar diffusion imaging at 1.5 T using b values of 0, 20, 40, 60, 80, 100, 200, 300, 400, and 500 seconds/mm2. Extravascular diffusion (D) and apparent diffusion coefficient (ADC) were calculated and results from both groups compared. RESULTS: Both D and ADC values tended to decrease with decreasing BMD. Mean D values were significantly lower in postmenopausal women with reduced BMD (0.42 +/- 0.12 x 10(-3) mm2/second) than normal premenopausal women (0.50 +/- 0.09 x 10(-3) mm2/second). Mean ADC values were significantly lower both in subjects with reduced BMD (0.41 +/- 0.10 x 10(-3) mm2/second) and normal BMD (0.43 +/- 0.08 x 10(-3) mm2/second) compared to normal controls (0.49 +/- 0.07 x 10(-3) mm2/second). CONCLUSION: Accumulation of fatty bone marrow associated with osteoporosis is reflected by a decrease in D and ADC. Diffusion imaging may prove useful in the study of osteoporosis.

Epidemiological determinants of spread of causal agent of severe acute respiratory syndrome in Hong Kong.

BACKGROUND: Health authorities worldwide, especially in the Asia Pacific region, are seeking effective public-health interventions in the continuing epidemic of severe acute respiratory syndrome (SARS). We assessed the epidemiology of SARS in Hong Kong. METHODS: We included 1425 cases reported up to April 28, 2003. An integrated database was constructed from several sources containing information on epidemiological, demographic, and clinical variables. We estimated the key epidemiological distributions: infection to onset, onset to admission, admission to death, and admission to discharge. We measured associations between the estimated case fatality rate and patients' age and the time from onset to admission. FINDINGS: After the initial phase of exponential growth, the rate of confirmed cases fell to less than 20 per day by April 28. Public-health interventions included encouragement to report to hospital rapidly after the onset of clinical symptoms, contact tracing for confirmed and suspected cases, and quarantining, monitoring, and restricting the travel of contacts. The mean incubation period of the disease is estimated to be 6.4 days (95% CI 5.2-7.7). The mean time from onset of clinical symptoms to admission to hospital varied between 3 and 5 days, with longer times earlier in the epidemic. The estimated case fatality rate was 13.2% (9.8-16.8) for patients younger than 60 years and 43.3% (35.2-52.4) for patients aged 60 years or older assuming a parametric gamma distribution. A non-parametric method yielded estimates of 6.8% (4.0-9.6) and 55.0% (45.3-64.7), respectively. Case clusters have played an important part in the course of the epidemic. INTERPRETATION: Patients' age was strongly associated with outcome. The time between onset of symptoms and admission to hospital did not alter outcome, but shorter intervals will be important to the wider population by restricting the infectious period before patients are placed in quarantine.

Transmission dynamics of the etiological agent of SARS in Hong Kong: impact of public health interventions.

We present an analysis of the first 10 weeks of the severe acute respiratory syndrome (SARS) epidemic in Hong Kong. The epidemic to date has been characterized by two large clusters-initiated by two separate "super-spread" events (SSEs)-and by ongoing community transmission. By fitting a stochastic model to data on 1512 cases, including these clusters, we show that the etiological agent of SARS is moderately transmissible. Excluding SSEs, we estimate that 2.7 secondary infections were generated per case on average at the start of the epidemic, with a substantial contribution from hospital transmission. Transmission rates fell during the epidemic, primarily as a result of reductions in population contact rates and improved hospital infection control, but also because of more rapid hospital attendance by symptomatic individuals. As a result, the epidemic is now in decline, although continued vigilance is necessary for this to be maintained. Restrictions on longer range population movement are shown to be a potentially useful additional control measure in some contexts. We estimate that most currently infected persons are now hospitalized, which highlights the importance of control of nosocomial transmission.