Comparison of the Physical Function Trajectories in Three Birth Cohorts of Chinese Older Adults: A 14-Year Longitudinal Study

OBJECTIVES

It remains uncertain whether the favorable trend of reduction in physical disabilities has become reversed in the recent-born cohorts of older adults. This study aimed to compare the rate of decline with time in self-reported Instrumental Activity of Daily Living (IADL) difficulties, objective measurement of gait speed and grip strength, in three birth cohorts of Chinese older adults.

DESIGN

A prospective cohort study.

SETTING AND PARTICIPANTS

Four thousand Chinese older adults aged 65 years or above in three birth cohorts (1934-1938, 1929-1933, 1905-1928) were recruited from the community in Hong Kong.

MEASUREMENTS

Grip strength, gait speed and IADL difficulties were measured between 2001 to 2017. Joint models were used to examine the trajectories of grip strength, gait speed and IADL difficulties over time, and the interaction effect of age-by-cohort (or also age2-by-cohort) was also examined.

RESULTS

The recently born cohort (1934 - 1938) had worse grip strength and more IADL difficulties at the same age than the earlier two cohorts (1929 - 1933; 1905 - 1928). Furthermore, the most recently born cohort also followed a more rapid decline longitudinally with a greater decline observed in gait speed, grip strength and IADL difficulties for women whereas a greater decline in grip strength and IADL difficulties for men.

CONCLUSIONS

The continuous improvement of physical limitations in old age may have halted and there appears to be a reversal of this favourable trend in the recent born cohort of older adults living in Hong Kong.

Hip fractures are preventable: a proposal for osteoporosis screening and fall prevention in older people

Osteoporosis is highly prevalent but underdiagnosed and undertreated in Hong Kong. Fragility fractures associated with osteoporosis often result in loss of independence and increased mortality for home-dwelling patients, imposing a high socio-economic burden on society. This issue requires urgent attention given the rapid growth of the elderly population in Hong Kong by approximately 4.3% each year. To address this situation, a group of experts convened to discuss practical ways to reduce the burden of fractures and formulated three recommendations: first, all men (aged ≥70 years) and women (aged ≥65 years) should receive universal dual-energy X-ray absorptiometry assessment for osteoporosis. Second, all men (aged ≥70 years) and women (aged ≥65 years) with a fracture-risk assessment-derived 10-year risk (hip fracture with bone mineral density) ≥3% should receive ≥3 years of anti-osteoporotic treatment. Third, comprehensive structured assessment (including dual-energy X-ray absorptiometry) should be conducted in older patients with a history of falling. By implementing these recommendations, we estimate that we could prevent 5234 hip fractures in 10 years, an annual incidence reduction of approximately 7%, and save HK$425 million in direct medical costs plus substantial indirect savings. Ample clinical and cost-effectiveness data support these recommendations, and studies in Hong Kong and abroad could serve as models on how to implement them. We are confident that by applying these recommendations rigorously and systematically, a significant reduction in hip fractures in Hong Kong is achievable.

Elderly males with or without existing osteoporotic vertebral fracture have much lower future vertebral fracture risk than elderly females: the MrOS (Hong Kong) year-4 follow-up spine radiograph study

MrOS (Hong Kong)'s year-4 follow-up shows, for subjects at baseline without vertebral deformity (VD) and endplate or/and cortex fracture (ECF), the VD progression/new VD rate during follow-up in males was half of our paired MsOS (Hong Kong) study's results. For those with VD or ECF, the VD progression/new VD was less than one sixth of females' rate.

INTRODUCTION

This study documents MrOS (Hong Kong)'s year-4 follow-up, and the results are compared with the MsOS (Hong Kong) study. Of elderly females with Genant's grade-0, -1, -2, and -3 VD, at year-4 follow-up, 4.6%, 8%, 10.6%, and 28.9% had at least one VD progression or incident VD, respectively.

METHODS

Spine radiographs of 1500 Chinese males with baseline (mean age 71.7 years, range 65-91 years) and year-4 follow-up were evaluated according to Genant's VD criteria and ECF (non-existent, ECF0; or existent, ECF1). Grade-2 VDs were divided into mild (VD2m, 25-34% height loss) and severe (VD2s, 34-40% height loss) subgroups. Study subjects were graded into eight categories: VD0/ECF0, VD1/ECF0, VD2m/ECF0, VD0/ECF1, VD1/ECF1, VD2m/ECF1, VD2s/ECF1, and VD3/ECF1. With an existing VD, a further height loss of ≥ 15% was a VD progression. A new VD incident was a change from grade-0 to grade-2/3, or to grade-1 with ≥ 10% height loss.

RESULTS

Of subjects with Genant's grade-0, 2.05% (25/1219) developed at least one VD progression or/and new VD, while of subjects with Genant's grade-1, -2, and -3 VD, only 2% (3/149), 3.1% (3/96), and 2.8% (1/36) developed at least one VD progression/new VD, respectively. Among the three ECF0 groups, there was a significant difference in new ECF incidence, with VD0/ECF0 being the lowest and VD2m/ECF0 being the highest.

CONCLUSION

VD progression/new VD is much less common in elderly men than in elderly women. Vertebrae with VD had a higher risk of developing ECF.

Osteoporotic vertebral deformity with endplate/cortex fracture is associated with higher further vertebral fracture risk: the Ms. OS (Hong Kong) study results

Compared with vertebrae without deformity, vertebrae with mild/moderate deformity have a higher risk of endplate or/and cortex fracture (ecf). Compared with subjects without ecf, subjects with ecf are at a higher risk of short-term (4-year period) deformity progression and new incident deformity.

INTRODUCTION

The progression and incidence of osteoporotic vertebral deformity/fracture (VD/VF) in elderly Chinese females remain not well documented.

METHODS

Spine radiographs of 1533 Chinese females with baseline and year-4 follow-up (mean age 75.7 years) were evaluated according to Genant's VD criteria and endplate/cortex fracture (non-existent: ecf0 or existent: ecf1). Grade-2 VDs were divided into mild (vd2m, 25-34% height loss) and severe (vd2s, 34-40% height loss) subgroups. According to their VD/VF, subjects were graded into seven categories: vd0/ecf0, vd1/ecf0, vd2m/ecf0, vd1/ecf1, vd2m/ecf1, vd2s/ecf1, and vd3/ecf1. With an existing VD, a further height loss of ≥ 15% was a VD progression. A new incident VD was a change from grade-0 to grade-2/3 or to grade-1 with ≥ 10% height loss.

RESULTS

Of subjects with Genant's grades 0, - 1, - 2, and - 3 VD, at follow-up, 4.6%, 8%, 10.6%, and 28.9% had at least one VD progression or new incident VD respectively. Among the three ecf0 groups, there was no difference in VD progression or new VD; while there was a significant difference in new ecf incidence, with vd0/ecf0 being lowest and vd2m/ecf0 being highest. Vd1/ecf0 and vd2m/ecf0 vertebrae had a higher risk of turning to ecf1 than vd0/ecf0 vertebrae. If vd1/ecf0 and vd2m/ecf0 subjects were combined together (range 20-34% height loss) to compare with vd1/ecf1 and vd2m/ecf1 subjects, the latter had significantly higher VD progression and new VD rates.

CONCLUSION

Vertebrae with grade-1/2 VDs had a higher risk of developing ECF. Subjects with pre-existing ECFs had a higher risk of worsening or new vertebral deformities.

Cost-effectiveness of osteoporosis screening strategies for hip fracture prevention in older Chinese people: a decision tree modeling study in the Mr. OS and Ms. OS cohort in Hong Kong

Despite the high costs of hip fracture, many governments provide limited support for osteoporosis screening. We demonstrated that osteoporosis screening by dual-energy X-ray absorptiometry (DXA) with or without pre-screening by Fracture Risk Assessment Tool (FRAX) or calcaneal ultrasound are more cost-effective than no screening in Chinese people aged 65 or over in Hong Kong.

INTRODUCTION

To examine the cost-effective potential osteoporosis screening strategies for hip fracture prevention in Hong Kong.

METHODS

Decision tree models were constructed to evaluate the cost per quality-adjusted life years (QALYs) of the different osteoporosis screening strategies followed by subsequent 5-year treatment with alendronate compared to no screening (but treat if a hip fracture occurs). The multiple osteoporosis screening strategies were composed of alternative tests and initiation age groups were evaluated with a 10-year horizon, and treatment were assigned if central dual-energy X-ray absorptiometry (DXA) T-score (at either the hip or spine) is - 2.5 or less. Strategies included DXA for all people and pre-screening with the Fracture Risk Assessment Tool (FRAX) at specific thresholds or by calcaneal quantitative ultrasonography (QUS) before taking DXA examination. All the model inputs were based on the Mr. OS and Ms. OS Hong Kong cohort; data are obtained from the Social Welfare Department or the published literature.

RESULTS

All of the screening strategies, including the universal screening with DXA and the pre-screening with FRAX or QUS before DXA, were consistently more cost-effective than no screening for people aged 65 years old or over. One-way sensitivity analysis with a more optimistic assumption on treatment adherence or inclusion of other major osteoporotic fractures did not change the results materially. Probabilistic sensitivity analyses showed a dominant role of pre-screening with FRAX followed by subsequent osteoporosis drug treatment in people aged 70 years old or over in Hong Kong.

CONCLUSIONS

Osteoporosis screening strategies based on DXA with or without pre-screening are more cost-effective compared to no screening for Chinese people aged 65 or over in Hong Kong.

Prevalence and risk factors of radiographic vertebral fractures in elderly Chinese men and women: results of Mr. OS (Hong Kong) and Ms. OS (Hong Kong) studies

This study investigated the prevalence of radiographic vertebral fractures using Genant's semiquantitative (SQ) scoring system in elderly Chinese men (n = 2,000; mean age, 72.4 years) and women (n = 2,000; mean age, 72.6 years). Vertebral deformities had similar prevalence in elderly men (14.9 %) and women (16.5 %). Majority of the deformities in men were mild (9.9 %, grade = 1). The prevalence of vertebral fractures (grade ≥ 2) was 5.0 % among men and 12.1 % among women.

INTRODUCTION

Vertebral fracture is a serious consequence of osteoporosis and is often under-diagnosed. Researches on different ethnicities and territories to estimate the prevalence of vertebral fractures and to identify the risk factors are necessary.

METHODS

Mr. OS (Hong Kong) and Ms. OS (Hong Kong) represent the first large-scale cohort studies ever conducted on bone health in elderly Chinese men (n = 2,000) and women (n = 2,000). The current study investigated the prevalence of radiographic vertebral fractures in these subjects using Genant's SQ scoring system and identified risk factors for vertebral fractures.

RESULTS

The radiographs of all men (mean age, 72.4 years) and women (mean age, 72.6 years) were obtained. Six hundred twenty-seven subjects (15.7 %) had at least one vertebral deformity (SQ grade ≥ 1), including 297 men (14.9 %) and 330 women (16.5 %, p = 0.151). Three hundred forty-two participants (8.6 %) were defined as having at least one vertebra fracture (SQ grade ≥ 2), consisted of 100 men (5.0 %) and 242 women (12.1 %, p < 0.001). Older age, lower bone mineral density, lower physical activity, lower grip strength, fracture history, and low back pain were significantly associated with higher vertebral fracture rate for both men and women.

CONCLUSION

Vertebral deformity had similar prevalence in older men and women, while vertebral fracture was more common in women. Majority of deformities in men was mild. The vertebral deformity prevalence of women from this study is similar to previous reports of other East Asian women and Latin American women.

Sex steroids and bone health in older Chinese men

This study examines the association between sex steroids, bone mineral density (BMD), and incident fractures in 1,489 community-living Chinese men aged 65 and over. Chinese men with low serum estradiol levels display elevated bone loss and increased risk of fractures similar to findings in Caucasians.

INTRODUCTION

This study examines the association between serum total testosterone (TT), free testosterone (free T), estradiol (E(2)), bioavailable estradiol (bioE(2)), sex hormone binding globulin (SHBG), BMD, and incident fractures.

METHODS

This is a cohort study with 4-year follow-up in the community in Hong Kong SAR, China. One thousand four hundred eighty-nine community-living Chinese men aged 65 and over participated. Sex steroid levels and BMD were measured at baseline; BMD was repeated after 4 years of follow-up, and fracture incidence from ascertainment from hospital databases was determined over 4 years of follow-up.

RESULTS

The strongest age-adjusted positive association with total hip and femoral neck BMD was with bioE(2), followed by E(2). Greater bone loss occurred in the lowest quartile of E(2) and bioE(2). The lowest quartile of free T and bioE(2) and the two highest quartile of SHBG were associated with the highest percentage of participants with incident fractures. Those in the lowest quartile of E(2) and bioE(2) had approximately a 50% increased risk of incident fractures compared with the other three quartiles. This relationship remains significant for nonvertebral incident fractures (hip, radius, pelvis, and humerus) for E(2) only, but not bioE(2). Compared with the group with the three highest quartiles of TT and E(2), the group with the lowest quartile of both had approximately twice the risk of nonvertebral osteoporosis-related incident fractures.

CONCLUSION

Chinese men with low serum estradiol levels display elevated bone loss and increased risk of fractures similar to findings in Caucasians.

Relationship between gender, bone mineral density, and disc degeneration in the lumbar spine: a study in elderly subjects using an eight-level MRI-based disc degeneration grading system

The study cohort comprised 196 females and 163 males. Lumbar spine bone mineral density (BMD) and magnetic resonance imaging (MRI) were acquired. Females had more severe disc degeneration than males. Lumbar spine lower BMD was associated with less severe disc degeneration. Lumbar disc spaces were more likely to be narrower when vertebral BMD was higher.

INTRODUCTION

The purpose of this paper is to study the relationship between gender, BMD, and disc degeneration in the lumbar spine.

METHODS

The study cohort comprised 196 females and 163 males (age range 67-89 years) with no age difference between the two groups. Lumbar spine BMD was measured with dual X-ray densitometry, and MRI was acquired at 1.5 T. A subgroup of 48 males had additional lumbar vertebral quantitative computerized tomography densitometry. Lumbar disc degeneration was assessed using a MRI-based eight-level grading system.

RESULTS

Female subjects had more severe disc degeneration than male subjects. After removing age effect, a positive trend was observed between T-score and severity of lumbar disc degeneration. This was significant in female subjects while not significant in male subjects. Lumbar disc spaces were more likely to be narrowed when vertebral BMD was higher. These observations were more significant in the midlumbar region (L3/4 and L4/5) and less so at the thoracolumbar junction.

CONCLUSION

Female subjects tended to have slightly more severe lumbar disc degeneration than male subjects. Lower lumbar spine BMD was associated with less severe disc degeneration.

Impact of childhood experience of famine on late life health

OBJECTIVES

This study examines whether experience of famine during late childhood affect late life health.

DESIGN

Cross sectional cohort survey carried out from 2001-2004.

SETTING

Community in Hong Kong.

PARTICIPANTS

1,906 men and 1,826 women aged >or= 65 years living in the community.

MEASUREMENTS

We examined the impact of experience of famine during late childhood, defined as caloric restriction for at least one year, on body mass index, body composition using DEXA, grip strength, walking speed and stride length, blood pressure, and ankle-brachial index,using logistic regression adjusting for various co-variates (age, lifestyle, socioeconomic factors).

RESULTS

Participants who had been exposed to a period of undernutrition in late childhood were shorter, had higher body mass index (BMI) and appendicular lean mass/height2, higher prevalence of recurrent falls, higher prevalence of myocardial infarct, arthritis and back pain.

CONCLUSIONS

Late childhood undernutrition has some adverse impact on late life health and functional outcomes.

The effect of telomere length, a marker of biological aging, on bone mineral density in elderly population

Telomere length (TL), as a reflection of aging and inflammatory processes, may be associated with bone mineral density (BMD). This study examines the association between TL and BMD cross-sectionally and the rate of bone loss over a 4-year period in 1,867 Chinese elderly community living subjects. After adjusting for confounding factors, no association was observed with BMD or bone loss. The decline in BMD with aging is not reflected by corresponding changes in telomere length.

INTRODUCTION

Bone mineral density (BMD) is influenced by the dynamics of aging, inflammatory, and bone remodeling processes. Telomere length (TL) is a reflection of the former two processes and may also be associated with bone loss.

METHODS

Hip BMD was measured in 1,867 Chinese elderly community living subjects and the relationship between leukocyte TL measured using quantitative real-time polymerase chain reaction, and bone loss after 4 years was examined.

RESULTS

Women had greater bone loss than men. In women, age of menopause, menarche, estrogen treatment/replacement therapy, and history of previous fracture were also among the significant covariates. However, in multivariate analyses, TL was not associated with BMD in either sex.

CONCLUSIONS

TL was not associated with either baseline BMD or bone loss over 4 years and accounted for less than 1.6% of the baseline BMD.

Relationship between grip strength and bone mineral density in healthy Hong Kong adolescents

This study evaluated the magnitude of the correlations among grip strength, bone mineral density (BMD) and bone mineral content (BMC), after controlling for weight, height, pubertal development, weight-bearing activities and calcium intake. The results lead to the conclusion that grip strength is an independent predictor of bone mass in both sexes. The relationship between muscle strength and bone mass is systemic.

INTRODUCTION

Previous studies had shown a site-specific relationship between muscle strength and bone in pubertal children. This study evaluated the magnitude of the correlations among grip strength, bone mineral density (BMD) and bone mineral content (BMC) at distant bone.

METHODS

Cross-sectional data of 169 11- to 12-year-old boys and 173 10- to 11-year-old girls came from the baseline result of a cohort study. Grip strength, BMD, BMC, weight, height, pubertal development, weight-bearing activities and calcium intake were measured. Pearson correlations and multiple regressions were used to calculate univariate and adjusted associations among grip strength and bone mass at distant bone.

RESULTS

Significant correlations were shown between grip strength and bone mass at hip, spine and whole body (boys: BMC:0.72-0.74, BMD:0.38-0.60; girls: BMC:0.71-0.72, BMD:0.44-0.63; p<0.0001). Multiple regressions with all covariates showed that about 70% and 50%, respectively, of the variations in BMC and BMD could be explained but not for whole body BMD. Grip strength was an independent predictor of bone mass, except hip BMD in boys and whole body BMD in girls. Stepwise regression showed that grip strength was a robust predictor in both sexes. Prediction models by grip strength and weight explained about 60% and 40% of the variations in BMC of different sites and in BMD of hip and spine, respectively.

CONCLUSIONS

We found that grip strength is an independent predictor of bone mass in both sexes. The relationship between muscle strength and bone mass is systemic.

Telomeres and frailty

Associations between telomere length and various chronic diseases associated with ageing have led to the suggestion that telomere length may be an ageing biomarker. At the clinical level, the suggestion of using measurements of frailty as a measure of biological ageing has also been suggested. This study examines the hypothesis that telomere shortening may form the biological basis for frailty, using data obtained from a health survey of 2000 men and women aged 65 years and over, living in the community, and followed up for 4 years to determine survival. Frailty was measured using the frailty index, a summation of deficits covering physical, psychological, and functional domains. Telomere length was measured in 976 men and 1030 women, using real-time quantitative polymerase chain reaction. Women were more frail than men but had longer telomere length. In men only, there was a negative association between telomere length and age and a positive association between frailty index and mortality after adjusting for age. There was no correlation between telomere length and frailty index in either sex. While telomere length may be a biomarker of cellular senescence, this relationship may not be extrapolated to the functional level represented by the frailty phenotype.