An estimation of the functional disability burden in elderly Chinese age 70 years and over

A cross-sectional survey of functional status among elderly Hong Kong Chinese aged 70 years and over was carried out to estimate the current burden of disability. Two thousand and thirty-two subjects (999 men, 1033 women) were recruited by random sampling of the old age and disability allowance schemes covering over 90% of the elderly population, stratified by sex and 5-year age groups. Functional ability was administered using the Barthel Index. The duration of disability, if any, was also noted. The prevalence of disability for different activities of daily living varied from 0.8% to 26% (lowest for feeding and highest for climbing stairs and bathing). The prevalence was higher for women than men, and higher in the older age group for both sexes. Men in the 80+ age group had shorter duration of disability compared with those in the 70-79 age group, and compared with women. Using disability years (estimated number of elderly with disability in the population x median duration of disability) as an estimate of disability burden, the number ranges from approximately 19,000 (inability to feed) to 100,000 (inability to climb stairs). This estimate may be useful in the planning of service provisions for the formal and informal care sector.

Large trials vs meta-analysis of smaller trials: how do their results compare?

OBJECTIVE

To evaluate the results of large clinical trials vs the pooled results of smaller trials.

DATA IDENTIFICATION

Meta-analyses with at least 1 "large" study were identified from the Cochrane Pregnancy and Childbirth Database and from MEDLINE (1966-1995).

STUDY SELECTION

We used a sample size approach to select 79 meta-analyses with at least 1 large study of 1000 or more patients. We used a statistical power approach to select 61 meta-analyses with at least 1 large study based on statistical power considerations.

DATA EXTRACTION

The outcome of interest for each meta-analysis was the primary one stated in the original publication or, when not clearly specified, was decided on clinically.

DATA SYNTHESIS

By random effects calculations, we found agreement between large and smaller trials in 90% of the meta-analyses selected by the sample size approach and in 82% of the meta-analyses selected by the statistical power approach. Twice as many disagreements appeared when the variability among large studies and among smaller studies was not considered (ie, fixed effects calculations). Of the 15 disagreements between results of large and smaller trials using the random effects model, plausible explanations were identified in 10 meta-analyses: 5 with differences in the control rate of events between large and smaller trials, 4 with specific protocol or study differences, and 1 with potential publication bias. Two other disagreements were not clinically important, and tentative reasons could be identified for 2 of the remaining 3 disagreements.

CONCLUSIONS

Results of smaller studies are usually compatible with the results of large studies, but discrepancies do occur even when the diversity among both large studies and smaller studies is considered. Clinically important differences without a potential explanation are extremely uncommon. Future research should further examine sources of heterogeneity between the results of large and smaller trials.

Uncertainty of the time of first significance in random effects cumulative meta-analysis

We propose a process for evaluating quantities of clinical and statistical interest in cumulative meta-analysis. We use Monte Carlo simulation studies to assess the error variance of the time to significance in cumulative meta-analysis. For the specific cumulative meta-analyses that we simulated, the 95% confidence interval of the treatment effect, estimated by the random effects method at the time of earliest significance, appears to be approximately appropriate except when the hypothesized treatment effect is near the null. The Monte Carlo approach that we used can also estimate the power of a cumulative meta-analysis when two treatments differ in efficacy. We illustrate these issues in the context of five cumulative meta-analyses, each comparing two treatments for preventing mortality from myocardial infarction. These simulated meta-analyses demonstrate our main point, which is that the time of first significance, however parameterized, is itself a random variable with error variance.

Gender-based mortality follow-up from the Program on the Surgical Control of the Hyperlipidemias (POSCH) and meta-analysis of lipid intervention trials. Women in POSCH and other lipid trials

OBJECTIVE

The authors assessed the clinical results of lipid-lowering therapy in women.

SUMMARY BACKGROUND DATA

The Program on the Surgical Control of the Hyperlipidemias (POSCH) has demonstrated that effective lowering of total cholesterol and low-density lipoprotein cholesterol in a postmyocardial infarction population significantly reduces atherosclerotic coronary heart disease (ACHD) mortality, ACHD mortality combined with a new confirmed nonfatal myocardial infarction, and the number of coronary artery bypass grafting and angioplasty procedures performed.

METHODS

A review and meta-analysis were performed of the seven primary or secondary lipid/ atherosclerosis intervention trials-including POSCH-published in the English-language literature that included women and published results in women separate from the results in men or in the entire trial population. The main outcome measure analyzed was overall mortality.

RESULTS

The Scottish Physicians Clofibrate Study, the Newcastle upon Tyne Clofibrate Study, and the Pravastatin Limitation of Atherosclerosis in the Coronary Arteries (PLAC I) Trial may have demonstrated a possible benefit in ACHD prognosis from effective lipid intervention in women. The other four available trials did not. The Minnesota Coronary Survey reported a 15.6% increase in overall mortality rate and a 30.6% increase in a combined cardiovascular endpoint rate in the lipid-intervention group. The Upjohn Colestipol Study demonstrated statistically significant reductions in overall and ACHD mortality in the men, but not in the women. The Scandinavian.

Changes in clinical trials mandated by the advent of meta-analysis

Service on the Data Monitoring Committee of the CPEP (Calcium for Pre-eclampsia Prevention) has led us to four conclusions about clinical trials which we should like to present to this gathering of biostatisticians for their reactions: (i) meta-analyses of the pertinent published trials of the same therapy should always be undertaken before the start of a new trial, and the results examined to help determine the design of a new trial or determine if a trial should be undertaken at all; (ii) assuming that a decision is made to go ahead, the results of the past trials should be used in sizing the new one; (iii) in the course of the new one, regardless of the size estimates, stopping early should be considered if the trends conform to the results of the meta-analysis; and (iv) heterogeneity of patients entering clinical trials is desirable and should be specifically studied, and it should never be concluded that an average outcome is applicable to all future patients.

The effect of dietary protein restriction on the progression of diabetic and nondiabetic renal diseases: a meta-analysis

BACKGROUND

Dietary protein has long been thought to play a role in the progression of chronic renal disease, but clinical trials to date have not consistently shown that dietary protein restriction is beneficial.

PURPOSE

To use meta-analysis to assess the efficacy of dietary protein restriction in previously published studies of diabetic and nondiabetic renal diseases, including the recently completed Modification of Diet in Renal Disease Study.

DATA SOURCES

The English-language medical literature published from January 1966 through December 1994 was searched for studies examining the effect of low-protein diets in humans with chronic renal disease. A total of 1413 patients in five studies on nondiabetic renal disease (mean length of follow-up, 18 to 36 months) and 108 patients in five studies of type I diabetes mellitus (mean length of follow-up, 9 to 35 months) were included.

STUDY SELECTION

Randomized, controlled studies were selected for nondiabetic renal disease; randomized, controlled studies or time-controlled studies with nonrandomized crossover design were selected for diabetic nephropathy.

DATA EXTRACTION

Data in tables, figures, or text were independently extracted by two of the authors.

DATA SYNTHESIS

The relative risk for progression of renal disease in patients receiving a low-protein diet compared with patients receiving a usual-protein diet was calculated by using a random-effects model. In five studies of nondiabetic renal disease, a low-protein diet significantly reduced the risk for renal failure or death (relative risk, 0.67 [95% Cl, 0.50 to 0.89]). In five studies of insulin-dependent diabetes mellitus, a low-protein diet significantly slowed the increase in urinary albumin level or the decline in glomerular filtration rate or creatinine clearance (relative risk, 0.56 [Cl, 0.40 to 0.77]). Tests for heterogeneity showed no significant differences in relative risk among studies of either diabetic or nondiabetic renal disease. No significant differences were seen between diet groups in pooled mean arterial blood pressure (diabetic and nondiabetic patients) or glycosylated hemoglobin level (diabetic patients only).

CONCLUSION

Dietary protein restriction effectively slows the progression of both diabetic and nondiabetic renal diseases.

Predictive value of viral load measurements in asymptomatic untreated HIV-1 infection: a mathematical model

OBJECTIVE

To model the predictive value of viral load measurements in asymptomatic patients with HIV-1 infection, who have CD4 cell counts > 500 x 10(6)/l and no prior antiretroviral therapy, when the time of seroconversion and the prior levels of viremia are unknown.

DESIGN

A mathematical model was constructed for the changes in HIV RNA load over time based on data from cohorts of HIV-infected patients followed since the time of seroconversion.

METHODS

For different values of viral load, the time to progression to AIDS or an equivalent state [progression to AIDS equivalent (PAE)] was calculated using a wide range of estimates for the time since seroconversion and the rate of change of the viral load over time.

RESULTS

In the absence of antiretroviral treatment, patients with a viral load of 10(5) copies/ml serum are at risk for PAE in less than 3 years (0-3 years) and patients with a viral load half a log higher are at risk in less than 1 year. In contrast, patients with a viral load of 10(4.5) have at least 1.9 years and may have up to 8 years before risk of PAE. Patients with a viral load of 10(4) RNA copies/ml have at least 2.8 years and may have up to 19 years before risk of PAE. The rate of change of the viral load was an important predictor of outcome; the time since seroconversion had only a minor effect.

CONCLUSIONS

The viral load in the plasma or serum has predictive value even if the time of seroconversion is unknown. The rate of change of viral load over time may also be an important predictive factor. Serial measurements of viral load over time may provide therapeutic guidance.

Single or multiple daily doses of aminoglycosides: a meta-analysis

OBJECTIVE

To assess relative efficacy and toxicity of aminoglycosides given by single daily dose compared with multiple daily doses.

DESIGN

Meta-analysis of 21 randomised trials identified through MEDLARS (1966 to January 1995). Data were overviewed with fixed effects and random effects models and with meta-regression analysis.

SUBJECTS

Total of 3091 patients with bacterial infection, most without pre-existing renal disease.

INTERVENTIONS

Patients were randomized to receive aminoglycosides once daily or multiple times daily with similar total daily dose.

MAIN OUTCOME MEASURES

Clinical failure of treatment, nephrotoxicity, ototoxicity, and mortality.

RESULTS

Single daily dose regimen produced a non-significant decrease in risk of antibiotic failures (random effects risk ratio 0.83 (95% confidence interval 0.57 to 1.21)). Benefit of once daily dosing was greater when the percentage of pseudomonas isolates in a trial was larger. Once daily administration reduced risk of nephrotoxicity (fixed effects risk ratio 0.74 (0.54 to 1.00)). Similar trends were noted for patients with febrile neutropenia and for children. There was no significant difference in ototoxicity between the two dosing regimens, but the power of the pooled trials to detect a meaningful difference was low. There was no significant difference in mortality.

CONCLUSIONS

Once daily administration of aminoglycosides in patients without pre-existing renal impairment is as effective as multiple daily dosing, has a lower risk of nephrotoxicity, and no greater risk of ototoxicity. Given the additional convenience and reduced cost, once daily dosing should be the preferred mode of administration.

Anthropometric measurements and body proportions among Chinese children

There are significant racial differences in body proportions. Such data are not readily available for Chinese children. This article reports a cross section study of body proportions of 2193 Hong Kong Chinese children, ages 4 to 16 years, with equal gender distribution. Standing height, sitting height, and arm span were measured with standard equipment and methodology. Lower segment height was calculated as the difference between standing height and sitting height. Statistical analysis of the results showed a high linear correlation of the standing height with arm span, sitting height, and lower segment height, with a correlation coefficient ranging from 0.965 to 0.983 for both genders. When expressed as the ratio of standing height to arm span, the value was relatively constant and changed only linearly from 1.03 to 1 in girls and 1.03 to 0.98 in boys ages 4 to 16 years. The ratio of sitting height to lower segment height varied from a mean of 1.4 to 1.14 in boys and 1.36 to 1.18 in girls ages 4 to 16 years. The Chinese children were found to have a proportional limb segmental length relative to the trunk that differed significantly from the proportionally longer limbs in whites and blacks.

A meta-analysis of the relative efficacy and toxicity of Pneumocystis carinii prophylactic regimens

BACKGROUND

Finding the optimal strategy for Pneumocystis carinii prophylaxis in patients with human immunodeficiency virus infection can be problematic. Several prophylactic regimens are available, but their relative efficacy and tolerance are not well understood.

METHODS

A meta-analysis overviewed 35 randomized trials comparing different regimens for P carinii prophylaxis directly or with placebo. Analyses were based on intention-to-treat. On-treatment data were also analyzed when available.

RESULTS

Regardless of dose, sulfamethoxazole-trimethoprim was almost universally effective for patients who tolerated it. The risk of discontinuing sulfamethoxazole-trimethoprim because of side effects decreased by 43% (95% confidence interval, 30% to 54%) if one double-strength tablet was given three times a week instead of daily. For dapsone, among 100 patients given 100 mg daily instead of twice a week for 1 year (primary prophylaxis), seven fewer patients would develop P carinii pneumonia, but 17 more would have significant toxic reactions. Aerosolized pentamidine was well tolerated regardless of the dose used. Prophylaxis failures might be halved if the dose of aerosolized pentamidine were doubled. Compared with aerosolized pentamidine, oral regimens prevented 73% (95% confidence interval, 57% to 82%) of toxoplasmosis events by on-treatment analysis, but only 33% (95% confidence interval, 12% to 50%) by intention-to-treat. No significant difference in mortality was demonstrated between different regimens.

CONCLUSIONS

Sulfamethoxazole-trimethoprim is the superior regimen, and low doses could improve tolerance without losing effectiveness for primary prophylaxis. Low doses of dapsone reduce toxic effects, but at the expense of some loss of efficacy. There are few data on the use of low-dose regimens for secondary prophylaxis. High doses of aerosolized pentamidine may improve the efficacy of this regimen. Aerosolized pentamidine is inadequate for prevention of toxoplasmosis, and strategies that improve the tolerance of oral regimens may increase effectiveness in preventing toxoplasmosis.

Respiratory symptoms in elderly Chinese living in Hong Kong

Respiratory diseases can cause considerable disability in the elderly because of their limited respiratory reserve as a result of ageing. We have investigated the prevalence of respiratory symptoms and diseases in elderly Chinese in Hong Kong and compared these data with those in elderly Caucasian populations. Two thousand and thirty two (999 male and 1,033 female) subjects, selected by age-stratified random sampling from a register of Hong Kong residents aged 70 yrs and over were interviewed to complete a respiratory questionnaire. Total serum immunoglobulin E (IgE) was measured in 195 subjects. At least one respiratory symptom was reported by 56% of subjects. The most frequently reported symptoms were morning phlegm (26%), chronic cough with phlegm (10%) and wheeze in the past 12 months (8%). Of the self-reported diseases, the commonest was chronic bronchitis (7%), followed by asthma (5%), pulmonary tuberculosis (3%) and emphysema (2%). Of the 218 subjects with obstructive airway diseases, 128 (59%) had sought medical advice in the past 12 months. The most important determinants for respiratory symptoms and diseases were smoking and social class. Total serum IgE was significantly higher in current smokers than nonsmokers and also in those with chronic cough and phlegm than those without these complaints. Our study shows that respiratory ailments in Hong Kong elderly are as common as those reported in Sweden and the USA but less than those in England.

The efficacy of influenza vaccine in elderly persons. A meta-analysis and review of the literature

OBJECTIVE

To quantify the protective efficacy of influenza vaccine in elderly persons.

DATA SOURCES

A MEDLINE search was done using the index terms influenza vaccine, vaccine efficacy, elderly, mortality, hospitalized, and pneumonia. Appropriate references in the initially selected articles were also reviewed.

STUDY SELECTION

Only cohort observational studies with mortality assessment were included in the meta-analysis. In addition, 3 recent case-control studies, 2 cost-effectiveness studies, and 1 randomized, double-blind, placebo-controlled trial were reviewed.

DATA EXTRACTION

Vaccine and epidemic virus strains, age and sex of patients, severity of illness, patient status, and study design were recorded. Upper respiratory illness, hospitalization, pneumonia, and mortality were used as outcome measures.

DATA SYNTHESIS

In a meta-analysis of 20 cohort studies, the pooled estimates of vaccine efficacy (1-odds ratio) were 56% (95% Cl, 39% to 68%) for preventing respiratory illness, 53% (Cl, 35% to 66%) for preventing pneumonia, 50% (Cl, 28% to 65%) for preventing hospitalization, and 68% (Cl, 56% to 76%) for preventing death. Vaccine efficacy in the case-control studies ranged from 32% to 45% for preventing hospitalization for pneumonia, from 31% to 65% for preventing hospital deaths from pneumonia and influenza, from 43% to 50% for preventing hospital deaths from all respiratory conditions, and from 27% to 30% for preventing deaths from all causes. The randomized, double-blind, placebo-controlled trial showed a 50% or greater reduction in influenza-related illness. Recent cost-effectiveness studies confirm the efficacy of influenza vaccine in reducing influenza-related morbidity and mortality and show that vaccine provides important cost savings per year per vaccinated person.

CONCLUSION

Despite the paucity of randomized trials, many studies confirm that influenza vaccine reduces the risks for pneumonia, hospitalization, and death in elderly persons during an influenza epidemic if the vaccine strain is identical or similar to the epidemic strain. Influenza immunization is an indispensable part of the care of persons 65 years of age and older. Annual vaccine administration requires the attention of all physicians and public health organizations.

Efficacy and safety of combined anticoagulant and antiplatelet therapy versus anticoagulant monotherapy after mechanical heart-valve replacement: a metaanalysis

We performed a metaanalysis of five randomized controlled trials to compare the efficacy and safety of combined oral anticoagulant and antiplatelet therapy versus oral anticoagulants alone after prosthetic heart-valve replacement. The combined regimen reduced embolism and overall mortality by approximately 67% (pooled odds ratio [OR] 0.33; 95% confidence interval [CI] 0.16 to 0.69; p = 0.0032) and 40% (OR 0.60; 95% CI 0.32 to 1.12; p = 0.11), respectively, but increased the risk of hemorrhage by approximately 65% (OR 1.65; 95% CI 1.15 to 2.39; p = 0.0069) and of major gastrointestinal hemorrhage by approximately 250% (OR 3.47; 95% CI 1.43 to 8.40; p = 0.0058). It is estimated that for every 1.6 patients who had their stroke prevented by combination therapy, there was an excess of one major gastrointestinal bleed. This metaanalysis suggests that the benefits derived from the enhanced antithrombotic potential of combined therapy outweigh the toxic effects resulting from the enhanced anticoagulant potential of this regimen.

A randomized double-blind controlled calcium supplementation trial, and bone and height acquisition in children

There is limited information relating Ca intake to bone and height acquisition among Oriental children who consume little or even no milk. The present controlled study investigated the acquisition of bone mass and height of Chinese children with an initial Ca intake of approximately 567 mg/d who were supplemented to about 800 mg/d. Eighty-four 7-year-old Hong Kong Chinese children underwent an 18-month randomized, double-blind, controlled Ca-supplementation trial. The children were randomized to receive either 300 mg elemental Ca or a placebo tablet daily. Bone mass of the distal one-third radius was measured by single-photon absorptiometry, lumbar spine and femoral neck were determined using dual-energy X-ray absorptiometry. Measurements were repeated 6-monthly. Baseline serum 25-hydroxycholecalciferol concentration and physical activity were also assessed. Baseline Ca intakes of the study group and controls were respectively 571 (SD 326) and 563 (SD 337) mg/d. There were no significant differences in baseline serum 25-hydroxycholecalciferol concentration (P = 0.71) and physical activity (P = 0.36) between the study and control groups. After 18 months the study group had significantly greater increases in lumbar-spinal bone mineral content (20.9 v. 16.34%; P = 0.035), lumbar-spinal area (11.16 v. 8.71%; P = 0.049), and a moderately greater increment in areal bone mineral density of the radius (7.74 v. 6.00%; P = 0.081) when compared with the controls. The results confirm a positive effect of Ca on bone mass of the spine and radius but no effects on femoral-neck and height increase. A longer trial is warranted to confirm a positive Ca effect during childhood that may modify future peak bone mass.

Early or deferred zidovudine therapy in HIV-infected patients without an AIDS-defining illness

PURPOSE

To do a meta-analysis on the efficacy of early or deferred zidovudine monotherapy in patients with human immunodeficiency virus (HIV) infection but not the acquired immunodeficiency syndrome (AIDS).

DATA SOURCES

Articles on zidovudine monotherapy published through May 1994.

STUDY SELECTION

Double-blind, randomized, placebo-controlled trials addressing the efficacy of zidovudine monotherapy in HIV-infected persons without an AIDS-defining illness.

DATA EXTRACTION

Progression to any primary trial end point; any clinical end point; and AIDS or death. Data were stratified according to disease stage at study entry and duration of follow-up (short-term, < 14 months; long-term, > 21 months).

DATA SYNTHESIS

Early initiation of zidovudine therapy was of short-term benefit for all the end points evaluated (for example, the risk ratio for progression to any primary end point was 0.51; 95% CI, 0.41 to 0.64). Long-term trials showed a marginally significant trend of decreased progression to any primary end point (risk ratio, 0.73; CI, 0.52 to 1.03). The trend was not significant for other end points. With further stratification according to disease stage, progression to AIDS or death in the short term was significantly decreased for both symptomatic and asymptomatic patients with CD4 cell counts of less than 500 x 10(6)/L (risk ratios, 0.26 [CI, 0.13 to 0.56] and 0.43 [CI, 0.30 to 0.64], respectively). A regression analysis indicated a larger relative benefit in short-term trials and symptomatic patients than in long-term trials and asymptomatic patients.

CONCLUSIONS

Early initiation of zidovudine therapy offers a benefit that decreases over time. Symptomatic patients experience a larger benefit than asymptomatic patients. The implications beyond 3 years of follow-up remain unknown.

Determinants of bone mass in the Chinese old-old population

One hundred and eighty-eight elderly men and women were included in a study of bone mass at the neck of femur and its related factors. The study subjects were a subsample of a Hong Kong wide study of the elderly population aged 70 years and above. The study variables included age, sex, body measurements of height, weight, body mass index, dietary calcium intake, grip strength, 16 feet (5 m) gait speed, smoking, drinking, and years since menopause among women. The neck of femur bone mineral density among elderly men was about 1 standard deviation higher than that of women. Subjects aged 85 years and above had about 20% lower bone mineral density at the neck of femur when compared with those in the age group 70-74 years. Mean dietary calcium intake ranged between 300 and 430 mg/day and was not associated with bone mass. Multiple regression analysis showed that body weight, 16 feet gait speed, sex and alcohol consumption explained 46% of the total variance of femoral neck bone mineral density. Body weight was the most significant predictor of bone mineral density, with a partial correlation coefficient of 0.5. The maintenance of body weight within the acceptable weight range and promotion of physical fitness may be important measures in reducing bone loss in the elderly population.

Efficacy and safety of different aspirin dosages on vascular diseases in high-risk patients. A metaregression analysis

PURPOSE

To compare the efficacy and safety of different aspirin dosages in trials with patients at increased risk of vascular disease.

DATA SOURCES

Pertinent studies were selected using MEDLINE (1966 through 1992), weekly reviews of Current Contents (1970 through 1992), and references from review articles and editorials.

STUDY SELECTION

Thirty-six randomized control trials of aspirin compared with another dosage of aspirin or with placebo.

METHODS

The Mantel-Haenszel method of pooling odds ratios and metaregression involving log odds ratio (and the risk difference) on aspirin dosage, adjusting for the control rate and the mean length of follow up of the studies.

RESULTS

For all patients and for subgroups of patients with previous vascular conditions, there was no relationship between dose and vascular events. For all patients, a dose-response relation was not found with gastrointestinal hemorrhages and hemorrhagic stroke, but was found with gastrointestinal symptoms and withdrawals from side effects. For every 25 mg/day increase in aspirin dosage, the odds ratio of gastrointestinal symptoms and withdrawals increased, respectively, by 0.87% (99% Cl, 0.18 to 1.57%) and 0.94% (99% Cl, 0.06 to 1.82%). The corresponding absolute risk increases were 0.58 and 0.78 per 1,000 patients.

CONCLUSIONS

Direct and indirect comparisons of high-risk patients suggest no statistical differences in efficacy, gastrointestinal bleeds, and hemorrhagic strokes across aspirin dosages. These comparisons, however, suggest decreased risk of gastrointestinal symptoms and of withdrawals with lower doses of aspirin. More direct comparison studies are warranted that should contrast the benefits and risks to determine the net benefit.

Life satisfaction and associated factors in older Hong Kong Chinese

OBJECTIVE

To determine life satisfaction and its association with physical, functional, socioeconomic, psychological, and social support characteristics in Hong Kong Chinese aged 70 years and older.

DESIGN

Cross-sectional study.

SETTING

Territory-wide random sample of persons aged 70 years and older.

SUBJECTS

A total of 843 men and 714 women were selected by random sampling, stratified by age and sex, from the Old age and Disability Allowance Register, after exclusion of subjects with cognitive impairment.

MEASUREMENTS

Life satisfaction was assessed by the subjects' response to the question "Are you satisfied with life", using a 0 to 10-point linear scale. They were also asked to name the most important factor contributing to life satisfaction. Information was also obtained regarding physical health, functional ability, depressive symptoms, and socioeconomic factors.

RESULTS

There was a weak association between score and age. Health, adequate income to meet living expenses, and caring relatives were rated the most important factors (> 65%). Some of these factors were also those associated with a high life satisfaction score. Factors associated with a life satisfaction score greater than 6 points were higher social class and educational attainment, adequate income to meet living expenses, satisfactory living arrangement, Christianity, good social support, participation in social activities, functional independence, good self-perceived health, good hearing and vision, daily exercise, absence of recurrent falls, and low depressive symptom score. Multiple logistic regression identified having two or more relatives and tertiary education as positive associated factors, whereas inadequate income to meet expenses, dissatisfaction with living arrangement, nonparticipation in religious group activities, and a high depressive symptom score were negative associated factors.

CONCLUSION

In older Chinese, social factors such as the support provided by family members, as well as adequate income to meet living expenses, play a role equal to that of physical factors in contributing to life satisfaction.

Effects of double-blind controlled calcium supplementation on calcium absorption in Chinese children measured with stable isotopes (42Ca and 44Ca)

A double-blind controlled Ca supplementation trial was conducted for 6 months in thirty-four 7-year-old Chinese children from Hongkong and Jiangmen, China. The children were randomly allocated to the study group (n 17) or control group (n 17), and a CaCO3 tablet (300 mg Ca) or a placebo tablet was taken daily. True fractional Ca absorption (TFCA) was evaluated before and after the trial using stable isotopes: 8 mg 44Ca mixed in 100 g chocolate milk was given after an intravenous injection of 0.75 mg 42Ca. There was no significant difference in baseline TFCA between the study group (60.6 (SD 11.4)%) and the controls (58.2 (SD 9.0)%; P = 0.55). Serum 25-hydroxycholecalciferol levels were comparable between the two groups (P = 0.71). After 6 months, TFCA of the study group (55.6 (SD 12.7)%) was significantly lower than that of the controls (64.3 (SD 10.7)%; P = 0.015). By comparing the individual changes in TFCA after the trial between the two groups there was a non-significant reduction in TFCA (5.03 (SD 12.4)%; P = 0.11, Wilcoxon signed-rank test) in the study group (60.6-55.6%), whereas a significant increase in TFCA (6.17 (SD 7.7)%; P = 0.004, Wilcoxon signed-rank test) was observed in the controls (58.2-64.3%). The differential in TFCA between the two groups after 6 months was significantly different (P = 0.001), and remained significant after adjustment for baseline dietary intakes, weight and height by multiple-regression analysis (P = 0.003). If the mechanism of TFCA from chocolate milk in response to the treatment effects is similar to that from the total diet, then our results suggest that children with adequate vitamin D status can adapt to a change in Ca intake by adjusting the efficiency of TFCA. In corollary, children on habitually-low Ca diets have a higher TFCA than the counterparts with higher Ca diets.

Age-associated gait changes in the elderly: pathological or physiological?

AIM

To examine the role of disease-related factors and age-related physiological changes in affecting gait speed and stride length in the elderly.

SUBJECTS

925 men and 890 women aged 70 years and above who were ambulant, recruited by random sampling stratified according to age and sex, from all recipients of Old Age and Disability Allowance in Hong Kong.

DESIGN

Gait was assessed by measuring the time taken and the number of steps required to complete a 16-foot walk. Information on health and functional status, cognitive function, and depressive symptoms was collected, and anthropometric indices obtained. Factors affecting walking speed and stride were examined in the overall population and also after excluding those with physical disability or diseases.

RESULTS

Results were analyzed separately for men and women since mean walking speed was slower in women, who also took a larger number of steps. Age, coexisting disease, leg or back pain, poor vision, low level of physical activity, functional and cognitive impairment, high depressive symptom score, and anthropometric indices were all negatively associated with walking speed. Fallers also had slower speed. After excluding those with diseases or physical impairment, multivariate analysis showed that the only factors affecting speed were age in men, and age, height, and level of physical activity in women. Age and height were factors associated with stride length in men, and height only for women.

CONCLUSION

Both disease-related factors as well as age-related physiological changes contribute to the decline in walking speed and stride length.

Drug use in an elderly Chinese population: prevalence and associated factors

This study examined the pattern of drug use in an elderly population aged 70 years and over, and the factors associated with drug use. The study population was selected by stratified random sampling of all registered recipients of Old Age and Disability Allowance in Hong Kong. 997 men and 1,035 women were interviewed as part of a survey on physical, functional, mental health and social status of the elderly in Hong Kong. 71% of the sample took drugs, the prevalence being higher in women. The most common drugs taken were antihypertensives, skin preparations, vitamins and minerals, other cardiovascular drugs, antacids or H2 antagonists, and non-steroidal anti-inflammatory analgesics (all over 10%). Overall, 66% were using medications that were unlabelled. Factors associated with drug use that were examined included socioeconomic factors, educational level, physical health, cognitive function, depressive symptoms, functional ability, life satisfaction, and living arrangements. Multivariate analysis using forward stepwise logistic regression showed that the use of prescription drugs was associated with the presence of chronic disease, poor self-perceived health and being female. Use of > 5 drugs was associated with similar factors: presence of chronic disease, being female, and residence in institutions. The factors for use of non-prescription drugs were different: living in the community, presence of joint pain restricting activities, dissatisfaction with living arrangements, and age. Reducing the number of unlabelled drugs, restricting access to non-prescription drugs, improving access to doctors and patient education all might well be important measures in improving the therapeutic needs of this elderly population.

Cumulative meta-analysis of clinical trials builds evidence for exemplary medical care

Cumulative meta-analysis of clinical trials (a Bayesian interpretation for accumulating evidence) will profoundly affect medical care by summarizing evidence in the assessment of technology innovations. Application of the technique to the randomized control trials (RCTs) of streptokinase treatment of acute myocardial infarction, reduction of peri-operative mortality by antibiotic prophylaxis, and prevention of death from bleeding peptic ulcers has revealed efficacy years before it was suspected by any other means. Arrangement of the trials according to event rate in the controls, effect sizes, quality of the trials or according to covariables of interest has supplied unique information. If carried out prospectively the technique supplies invaluable information regarding indications for another trial, the number of patients necessary to determine the validity of past trends, and the type of patients who might be benefitted. Careful examination in a cumulative manner of the prior trials can reduce the need for future large trials.

The rational use of therapeutic drugs in the 21st century. Important lessons from cumulative meta-analyses of randomized control trials

The use of randomized control trials to assess the usefulness of therapeutic drugs over the last half century has brought significant benefits to patient care. The full potential benefits, however, have been only partially fulfilled because available data are frequently poorly used. Meta-analysis has emerged as an important tool for combining clinical evidence. Several examples are presented that compared the results of cumulative meta-analysis of randomized control trials with clinical expert recommendations. These comparisons demonstrated that clinical expert recommendations are often not synchronized with accumulating evidence, and this lack of recognition often resulted in delays in the acceptance of effective drugs and the slow abandonment of possibly harmful therapeutic practices. The problems of inappropriate therapeutic drug use will only intensify as new drugs are introduced and new uses for established drugs are proposed. The rational use of therapeutic drugs can be achieved only through the routine use of meta-analysis on high-quality clinical data. Some suggestions are made to improve the quality of the original research and the ways of assembling meta-analyses and disseminating their results.

Double-blind, controlled calcium supplementation and bone mineral accretion in children accustomed to a low-calcium diet

A randomized, double-blind, controlled calcium supplementation trial was conducted for 18 mo to determine its effects on bone acquisition and height increment in 162 7-y-old Chinese children (87 boys and 75 girls) with habitually low calcium intakes (280 mg/d). Distal one-third radial bone mineral content (BMC), area bone density (BMC/bone width), and height were evaluated every 6 mo. Baseline dietary intakes, serum 25-hydroxycholecalciferol, and physical activity were determined. The study group received 300 mg Ca/d as calcium carbonate; control subjects received placebo tablets. After 18 mo the study group had significantly greater gains in BMC (16.5% vs 13.97%; P = 0.02) and BMC/bone width (9.45% vs 6.31%; P = 0.0008) than the control subjects. The findings confirm a positive effect of calcium intake on bone acquisition but no effect on height increment. Whether a higher bone mass attained at age 8-9 y would be maintained and beneficial to future peak bone mass requires longitudinal investigation. Further study is warranted to determine calcium requirements for Chinese children.

Musculoskeletal complaints and associated consequences in elderly Chinese aged 70 years and over

OBJECTIVE

To determine the prevalence and sites of musculoskeletal complaints and some associated health consequences among elderly Chinese.

METHODS

A random sample of all subjects aged 70 years and over stratified by age and sex. Information collected by questionnaire at an interview.

RESULTS

Nineteen to 41% of subjects complained of pain at various sites restricting activities, with a higher prevalence for women. The most common 4 sites involved in order of frequency were knee, upper back, ankle/foot, and shoulder. Back pain increased with age in men to reach the same frequency as women in the 90+ age group. Between 6 to 10% of men and 9 to 14% of women used nonsteroidal antiinflammatory drugs. Pain limiting activities were associated with a lower Barthel index, use of walking aids, increased frequency of doctor consultations, sleep disturbance, and higher depressive symptom scores.

CONCLUSION

Prevention of conditions resulting in musculoskeletal complaints would be important in the promotion of healthy active life expectancy in the elderly.

Drug treatment of hypertension in the elderly: a meta-analysis

PURPOSE

A meta-analysis of the effect of antihypertensive drug treatment on mortality and morbidity in elderly patients.

DATA SOURCES

A literature search of published articles from January 1980 to February 1992.

STUDY SELECTION

Randomized controlled trials of drug treatment of hypertension with end points for elderly patients reported separately.

DATA EXTRACTION

Mortality or morbidity end points or both in patients older than 59 years were pooled by determination of typical odds ratio. A meta-regression was used to study heterogeneity.

RESULTS

Nine major trials with 15,559 patients older than 59 years were identified. Death rates in the control group varied between 2.7% and 77.2%; stroke and coronary mortality increased with the severity-of-illness rank (P < 0.001). Overall, treated patients had an approximately 12% reduction in all-cause mortality (odds ratio, 0.88; 95% CI, 0.80 to 0.97; 953 events compared with 1069 events, P = 0.009). There was a 36% reduction in stroke mortality (odds ratio, 0.64; CI, 0.49 to 0.82; 94 events compared with 149 events, P < 0.001) and a 25% reduction in coronary heart disease mortality (odds ratio, 0.75; CI, 0.64 to 0.88; 263 events compared with 350 events, P < 0.001). Coronary morbidity was reduced 15% (odds ratio, 0.85; CI, 0.73 to 0.99; 325 events compared with 379 events, P = 0.036), and stroke morbidity was reduced 35% (odds ratio, 0.65; CI, 0.55 to 0.76; 247 events compared with 382 events, P < 0.001).

CONCLUSION

Overall, treatment of hypertension in elderly patients produces a significant benefit in total mortality and cardiovascular morbidity and mortality. However, this benefit may be reduced in the oldest age groups.

Comparison of a standard and a sensitive thromboplastin in monitoring low intensity oral anticoagulant therapy

The greater precision in prothrombin time monitoring obtained using thromboplastins with low international sensitivity index (ISI) values are believed to result in improved patient care. The authors conducted a blinded prospective study of 84 random patients on low-intensity warfarin therapy who were monitored with either a sensitive (ISI, 1.3) or standard (ISI, 1.9) thromboplastin. For the patients monitored with standard and sensitive thromboplastins, respectively, no difference was found in the degree of anticoagulation (standard thromboplastin mean INR, 2.4 vs. 2.5, P = .37; sensitive thromboplastin mean INR, 2.6 vs. 2.6, P = .74; mean daily warfarin dose, 5.1 vs. 4.7 mg, P = .28) or efficacy (warfarin dosage adjustments, 117 vs. 116; clinic visits, 362 vs. 378; percentage of therapeutic INR determinations, 47% vs. 48%). In addition, no difference was found in bleeding prevalence or severity (.22 vs. .27 events per person-year observation). The authors concluded that monitoring anticoagulant therapy in the INR range of 2-3 with a standard thromboplastin may be comparable to monitoring with a more sensitive thromboplastin with respect to efficacy, safety, and degree of anticoagulation achieved.

Age and marital status are major factors associated with institutionalisation in elderly Hong Kong Chinese

STUDY OBJECTIVE

To determine the need for long term institutional care for elderly Chinese living in Hong Kong and factors associated with institutional living.

DESIGN

Survey by interviewer administered questionnaire of a stratified random sample of all recipients of old age or disability allowance covering 90% of the population.

SETTING

Survey performed in Hong Kong, a city on the south coast of China with an area of 1070 km2 and approximately six million people.

PARTICIPANTS

A total of 2032 subjects aged 70 years and over (999 men, 1033 women) participated.

MAIN RESULTS

Overall, 16% of the elderly live in institutions. The percentage is higher in women and in the older age group (81% for those aged 80 years and over). After adjusting for age and sex, the following factors were positively associated with institutionalisation: poor cognitive function, measures of functional disability, poor vision, Parkinson's disease, stroke, and past fractures. Multivariate analysis identified age and marital status as associated factors with the highest odds ratio (13.6 and 7.1 respectively), followed by various disability indicators.

CONCLUSION

The survey shows that requirements for long term care places are unlikely to be much affected by preventive measures, and would need to increase by about 30% by 2000 to cope with the projected increase in the number of elderly aged 70 years and over. Measures to provide sufficient trained personnel and policy for regulation of standards should be made.

Endoscopic assessment of blood flow in duodenal ulcers

The importance of blood flow in duodenal ulcer healing is unclear. Endoscopic reflectance spectrophotometry measures the index of oxygen saturation (ISO2), which is significantly correlated with blood flow. In 97 consecutive patients who presented with duodenal ulcer bleeding, the difference in the index of oxygen saturation (delta ISO2: ulcer margin ISO2 minus adjacent mucosa ISO2) was determined during the initial endoscopic examination. Endoscopic examinations were repeated until the ulcers had healed (n = 86). Relative to the adjacent mucosa, 78% of the ulcer margins had increased blood flow (positive delta ISO2) and 22% had decreased blood flow (negative delta ISO2). Stepwise multi-linear regression analysis selected delta ISO2, ulcer size, and stigmata of recent hemorrhage as predictors of delayed healing. A significant negative linear correlation between delta ISO2 and ulcer healing time (r = -0.35, p < 0.001, n = 86) was demonstrated. The scatter in the data precludes prediction of ulcer healing based on delta ISO2 measurement in an individual patient. Multi-variate logistic regression analysis selected concurrent medical illness, duodenal deformity, frequent use of non-steroidal anti-inflammatory drugs, and stigmata of recent hemorrhage as factors significantly associated with delayed (longer than 5 weeks) ulcer healing. The results support the hypothesis that prognostic factors are identifiable at the time of ulcer diagnosis, even in patients who present with bleeding. Blood flow remains an equivocal factor that deserves to be re-studied taking multiple measurements around the ulcer and including a larger number of slow healers.

Guidelines for meta-analyses evaluating diagnostic tests

OBJECTIVES

To introduce guidelines for the conduct, reporting, and critical appraisal of meta-analyses evaluating diagnostic tests and to apply these guidelines to recently published meta-analyses of diagnostic tests.

DATA SOURCES

Based on current concepts of how to assess diagnostic tests and conduct meta-analyses. They are applied to all meta-analyses evaluating diagnostic tests published in English-language journals from January 1990 through December 1991, identified through MEDLINE searching and by experts in the field.

STUDY SELECTION

Meta-analyses were included if at least two of three independent readers regarded their main purpose as the evaluation of diagnostic tests against a concurrent reference standard.

DATA EXTRACTION

By three independent readers on the extent to which meta-analyses fulfilled each guideline, with consensus defined as agreement by at least two readers.

DATA SYNTHESIS

The guidelines are concerned with determining the objective of the meta-analysis, identifying the relevant literature and extracting the data, estimating diagnostic accuracy, and identifying the extent to which variability is explained by study design characteristics and characteristics of the patients and diagnostic test. In general, the guidelines were only partially fulfilled.

CONCLUSION

Meta-analysis is potentially important in the assessment of diagnostic tests. Those reading meta-analyses evaluating diagnostic tests should critically appraise them; those doing meta-analyses should apply recently developed methods. The conduct and reporting of primary studies on which meta-analyses are based require improvement.

Benzodiazepines in the treatment of catatonic syndrome

During a 5-month period, 18 (8%) of 212 patients admitted to a psychiatric unit affiliated to a teaching hospital were found to have a catatonic syndrome associated with various nonorganic mental disorders. Signs and symptoms of motor retardation predominated the clinical presentations. In the course of a prospective, open study, all 18 patients were challenged by a small dose of oral lorazepam or intramuscular diazepam. Catatonic signs and symptoms in 2 patients showed an immediate, complete, and sustained response to the medication. The remaining 16 patients were maintained on 1 of the 2 benzodiazepines for the next 48 h when their motor status was re-evaluated. Significant clinical improvement was detected in all but 2 patients. However, 9 patients needed electroconvulsive treatment to achieve further improvement. Short-term benzodiazepine administration proved to be a safe and effective treatment of the catatonic syndrome.

The prevalence of depressive symptoms and predisposing factors in an elderly Chinese population

In a survey of elderly Chinese aged 70 years and over living in Hong Kong selected by stratified random sampling, the prevalence of depression was determined using the 15-item Geriatric Depression Scale using a cut-off point of 8 (sensitivity 96.3% and specificity 87.5% for this population). Subjects with moderate to severe cognitive impairment (CAPE I/O score < or = 7) were excluded. There were 877 men and 734 women. The adjusted overall prevalence for this population was 29.2% for men and 41.1% for women. The prevalence increased with age in men and was higher in women than in men. Univariate analysis identified many factors in the following areas that were associated with depression: socioeconomic characteristics, functional ability, physical health and social support. Stepwise logistic regression identified 16 factors predictive of depression: socioeconomic characteristics, such as borderline living expenses and dissatisfaction with living arrangement; poor social support, such as absence of an informal carer when ill, few relatives to turn to, and infrequent contact with neighbours and friends; functional disability, as indicated by a Barthel Index < 15, urinary incontinence and inability to do housework; and poor physical health--poor self perceived health, poor vision, difficulty with chewing, history of mental illness, frequent hospital admissions and increased level of symptoms such as poor memory, constipation and dizziness. Some of these factors may be amenable to intervention, and such measures may be important in reducing the high prevalence of depression in elderly people.

Prevalence of cognitive impairment and associated factors among elderly Hong Kong Chinese aged 70 years and over

The prevalence of cognitive impairment was determined in a random age- and sex-stratified sample of 2,011 elderly Hong Kong Chinese, aged 70 years and over, consisting of subjects living in the community and in institutions. The Information/Orientation Section of the Clifton Assessment Procedure was used as the screening instrument using a cutoff point of 7. The overall age-adjusted prevalence was 5% for men and 22% for women, and 15% for both sexes combined. Univariate analysis identified the following associated factors in order of magnitude of the odds ratio: age; history of Parkinson's disease; functional disability; female sex; low educational level; low social class; history of stroke, and low monthly income. Other diseases, such as heart disease, hypertension, chronic lung diseases or diabetes, were not associated factors. In multivariate analysis, all the above factors remained significant with the exception of a history of stroke. The prevalence figures are comparable to other Caucasian and Chinese studies, and the associated factors identified suggest that there may be room for prevention.

Cardiovascular symptoms, electrocardiographic abnormalities, and associated risk factors in an elderly Chinese population

The aim of this study was to determine the prevalence of angina and possible infarct (WHO cardiovascular questionnaire) and electrocardiographic abnormalities (Minnesota Coding) in elderly Chinese subjects aged 70+ years living in Hong Kong, and the association with some cardiovascular risk factors. A subsample of 197 subjects (96 men, 101 women) selected according to geographical area from a territory-wide health survey consisting of 2032 elderly subjects selected by an age and sex stratified random sampling method was studied. Overall, 7% of men and 9% of women had symptoms suggestive of angina, while 6% of men and 4% of women had symptoms suggestive of possible infarct. There were fewer symptoms in the 80+ age group. Forty-two percent of men and 35% of women had normal electrocardiograms. The prevalence of probable ischaemic heart disease (using the Whitehall Criteria) was 6% for men and 7% for women, while the figures for possible disease were 23% and 25%, respectively. The percentage with abnormalities increased with age. The prevalence of coronary heart disease defined by the presence of symptoms, a history of known disease plus use of medication, and electrocardiographic abnormalities suggestive of probable disease, was 26% for men and 27% for women. These findings were comparable with studies in elderly Caucasian populations. Only a higher socioeconomic grouping and lower HDL cholesterol were identified as associated risk factors. It is concluded that the prevalence of coronary heart disease in the elderly Chinese population in Hong Kong is at least as high in Caucasian populations, and few modifiable risk factors were identified in the elderly aged 70 years and over.

Bone mineral content of two populations of Chinese children with different calcium intakes

Bone mineral content (BMC) of 5-year-old Chinese children (115 children in Jiangmen, China and 128 children in Hong Kong) was evaluated by single-photon absorptiometry at the distal 1/3 radius. The mean (S.D.) calcium intakes of children of Jiangmen and Hong Kong were 244 (46) and 542 (332) mg/day, respectively. The mean BMC, weight and height of Jiangmen children were significantly less than Hong Kong children by 14%, 10% and 4%, respectively (P < 0.001). Multiple regression analysis showed that 62% of the variance in BMC was explained by bone width (BW), weight and regional location (P < 0.0001). A regional difference in BMC of 0.0303 g/cm (P < 0.0001) still remained after adjusting for BW and weight by multiple regression analysis. When comparing sub-groups of children in the two regions with comparable low current calcium intake at 5 years, the BMC of Jiangmen children was still significantly lower than Hong Kong children even when potential confounders were adjusted (P < 0.003). The study suggests that the regional discrepancy in BMC might be explained by long-term habitual calcium intake and physical activity.

Treatment of respiratory syncytial virus infection with recombinant interferon alfa-2a

A prospective randomised, double blind, controlled trial was conducted in 52 infants to determine whether recombinant interferon alfa-2a (INF-alpha-2a) would reduce the morbidity of acute bronchiolitis and the respiratory syncytial virus shedding time. All infants had a positive direct antigen immunofluorescence test for respiratory syncytial virus. INF-alpha-2a (50,000 IU/kg/day) or placebo was administered by daily intramuscular injection for three consecutive days. Sixteen infants received INF-alpha-2a and 36 received placebo treatment. The two groups were similar in demographic characteristics and initial oxygenation. The treatment group, however, had a significantly higher overall score for severity of illness at the start of treatment. More rapid drop of the clinical score was observed in the INF-alpha-2a group after treatment in the first three days and the two groups had similar clinical severity by day 3. There was no significant difference of the duration of viral shedding in the two groups. In conclusion, the overall clinical improvement was greater in the treatment group over the first three days, but the duration of viral shedding was not altered.

Meta-analytic stimulus for changes in clinical trials

The advent of meta-analysis, especially when performed cumulatively, raises many questions about how best to approach the conduct of clinical trials in the evaluation of new treatments. We need to be assured that bias is minimized by proper experimental procedures and that clinical data, on the whole and in subgroups, are presented so that they can be effectively combined in meta-analysis. We need to re-examine the idea that we should not start a randomized control trial unless sufficient patients are available to avoid reasonable type I and II errors. Meta-analyses will come to the rescue, provided trials continue to be published at the present rate. We need to perform meta-analyses before undertaking each additional trial, and we need to base estimates of trial size on past data as well as the expected control rates and the differences we do not want to miss. In clinical trials of new interventions attempting to disprove the null hypothesis may be inappropriate because past data so often suggest or even establish that it is not true. Furthermore we need to recognize that trends (p > 0.05) can be both clinically and statistically important, and we must abandon the notion that if p is not < 0.05, the treatment is ineffective. In performing meta-analyses we need to worry about minimizing bias and error and consider the differences between the random and fixed effects models and between reporting results as an odds ratio versus difference in risk, with the control rates given. Experiences with cumulative meta-analysis have required that we think about all of these problems.

Cesarean section to reduce perinatal transmission of human immunodeficiency virus. A metaanalysis

OBJECTIVE

Individual epidemiologic investigations into the association between type of delivery and perinatal HIV transmission have been suggestive but inconclusive. Metaanalysis was used in an attempt to establish if there is, at present, adequate evidence concerning the effectiveness of cesarean section in reducing vertical HIV transmission rates.

METHODS

The MEDLINE data retrieval system and other sources were used to identify studies containing data on the relationship between type of delivery and vertical HIV transmission. No randomized control trials were located. Six cohort studies identified were included in the metaanalysis. Crude and, in the only study in which these were available, adjusted data were extracted and pooled.

RESULTS

The overall weighted risk of perinatal HIV infection was 20.2% and 14.0% after vaginal and cesarean delivery, respectively. Pooling data of all studies showed a statistically significant difference of HIV perinatal transmission rates between cesarean and vaginal delivery (odds ratio 0.65; 95% CI, 0.43 to 0.99; P = 0.044) (Random effects model: DerSimonian and Laird method). Approximately 16 (95% CI, 76 to 9) HIV-infected women must deliver by cesarean in order to prevent 1 case of HIV perinatal infection.

CONCLUSIONS

Results of this study show that performing elective cesarean section in HIV-infected women is potentially an effective procedure. However, the nonexperimental nature of the available studies leads us to conclude that randomized control trials are indicated before setting specific guidelines for mode of delivery in HIV-infected women.

Relationship between long-term calcium intake and bone mineral content of children aged from birth to 5 years

This study evaluated Ca intake in Hong Kong Chinese children and examined the association between long-term Ca intake and bone mineral content (BMC) in children. Longitudinal dietary intake from birth to 5 years was obtained in 128 children (sixty-seven boys, sixty-one girls). Ca intakes were evaluated by dietary history and cross-checked with food frequency and 24 h recall. At age 5 years BMC was determined at the one-third distal radius of the right arm using single-photon absorptiometry. The mean Ca intake of 133 children at 5 years was 546 (SD 325) mg/d. Milk was the chief source of Ca (43.5%). From birth to 5 years, 90% of the children had been taking milk regularly. The mean BMC and bone width (BW) of these children were 0.317 (SD 0.042) g/cm and 0.756 (SD 0.074) cm respectively. BMC was not correlated with current intakes of Ca, energy and protein but was positively correlated with weight (r 0.57), height (r 0.47) and BW (r 0.66). However, cumulative Ca intake throughout the past 5 years showed significant correlation with BMC (r 0.235, P = 0.0133). The significant correlation remained even after weight, height, BW, sex, and cumulative intakes of energy and protein were adjusted in multiple regression analysis (r 0.248, P = 0.0107). Moreover, using principal component analysis, Ca intake during the 2nd year of life had the strongest correlation with BMC at 5 years (r 0.240, P = 0.02). Ca intake of Hong Kong Chinese children was higher than the RDA of the Food and Agriculture Organization/World Health Organization (1962) and achieved 66% of the current US recommendation (National Research Council, 1989). The increased regular milk consumption reflects a significant change in dietary habits of the younger generation. Children with a habitually higher Ca intake throughout the past 5 years, particularly in the 2nd year, were found to have higher BMC.

The prevalence of diabetes mellitus and impaired glucose tolerance among Hong Kong Chinese adults of working age

We studied 1513 employees (910 men and 603 women) from a public utility company and a regional hospital to document the prevalence of diabetes mellitus (DM) and impaired glucose tolerance (IGT) in the Chinese working population of Hong Kong using a 75-g oral glucose tolerance test and World Health Organisation (1985) criteria. The overall prevalence of DM was 4.5 (95% confidence interval: 3.5-5.7%) and that of IGT 7.3 (6.0-8.6%). The prevalence of DM was 5.1 (3.7-6.5%) in men and 3.6 (2.1-5.1%) in women, while that of IGT was 7.4 (5.7-6.5%) in men and 7.1 (5.1-9.1%) in women. The truncated age-adjusted rate of DM for age 30-64 is 7.7% which is comparable to the age-adjusted prevalence rates among Chinese living in Singapore and Mauritius but in marked contrast to the low prevalence rate in Chinese living in Mainland China. Among the diabetic subjects, 38.2% had been previously diagnosed and 32% gave a family history affecting at least one first degree relative. Using polychotomous logistic regression analysis, the independent predictive factors for the development of DM include age (t = 7.31, P < 0.001), family history (t = 5.1, P < 0.001), waist hip ratio (t = 4.05, P < 0.001) and body mass index (t = 4.62, P < 0.001). Our data further confirm that Hong Kong Chinese have a moderate to high susceptibility to non-insulin-dependent diabetes (NIDDM) when exposed to sufficient environmental and lifestyle factors. The high prevalence of IGT indicates a potential for the prevalence of DM to continue to rise unless effective preventive measures are implemented.