Randomised controlled trial of a general practice programme of home based exercise to prevent falls in elderly women

OBJECTIVE

To assess the effectiveness of a home exercise programme of strength and balance retraining exercises in reducing falls and injuries in elderly women.

DESIGN

Randomised controlled trial of an individually tailored programme of physical therapy in the home (exercise group, n = 116) compared with the usual care and an equal number of social visits (control group, n = 117).

SETTING

17 general practices in Dunedin, New Zealand.

SUBJECTS

Women aged 80 years and older living in the community and registered with a general practice in Dunedin.

MAIN OUTCOME MEASURES

Number of falls and injuries related to falls and time between falls during one year of follow up; changes in muscle strength and balance measures after six months.

RESULTS

After one year there were 152 falls in the control group and 88 falls in the exercise group. The mean (SD) rate of falls was lower in the exercise than the control group (0.87 (1.29) v 1.34 (1.93) falls per year respectively; difference 0.47; 95% confidence interval 0.04 to 0.90). The relative hazard for the first four falls in the exercise group compared with the control group was 0.68 (0.52 to 0.90). The relative hazard for a first fall with injury in the exercise group compared with the control group was 0.61 (0.39 to 0.97). After six months, balance had improved in the exercise group (difference between groups in change in balance score 0.43 (0.21 to 0.65).

CONCLUSIONS

An individual programme of strength and balance retraining exercises improved physical function and was effective in reducing falls and injuries in women 80 years and older.

Falls prevention over 2 years: a randomized controlled trial in women 80 years and older

BACKGROUND

after 1 year, a home-based programme of strength and balance retraining exercises was effective in reducing falls and injuries in women aged 80 years and older. The exercise programme had been individually prescribed by a physiotherapist during the first 2 months of a randomized controlled trial.

OBJECTIVE

we aimed to assess the effectiveness of the programme over 2 years.

SUBJECTS

women from both the control group and the exercise group completing a 1-year trial (213 out of the original 233) were invited to continue for a further year.

METHODS

falls and compliance to the exercise programme were monitored for 2 years.

RESULTS

81 (74%) in the control group and 71 (69%) in the exercise group agreed to continue in the study. After 2 years, the rate of falls remained significantly lower in the exercise group than in the control group. The relative hazard for all falls for the exercise group was 0.69 (95% confidence interval 0.49-0.97). The relative hazard for a fall resulting in a moderate or severe injury was 0.63 (95% confidence interval 0.42-0.95). Those complying with the exercise programme at 2 years had a higher level of physical activity at baseline, were more likely to have reported falling in the year before the study and had remained more confident in the first year about not falling compared with the rest of the exercise group.

CONCLUSIONS

falls and injuries can be reduced by an individually tailored exercise programme in the home. For those who keep exercising, the benefit continues over a 2-year period.

Psychotropic medication withdrawal and a home-based exercise program to prevent falls: a randomized, controlled trial

OBJECTIVE

To assess the effectiveness of psychotropic medication withdrawal and a home-based exercise program in reducing falls in older people.

DESIGN

A randomized controlled trial with a two by two factorial design.

SETTING

Seventeen general practices in Dunedin, New Zealand.

PARTICIPANTS

Women and men aged 65 years registered with a general practitioner and currently taking psychotropic medication (n = 93).

INTERVENTIONS

Two interventions: (1) gradual withdrawal of psychotropic medication versus continuing to take psychotropic medication (double blind) and (2) a home-based exercise program versus no exercise program (single blind).

MEASUREMENTS

Number of falls and falls risk during 44 weeks of follow-up. Analysis was on an intent to treat basis.

RESULTS

After 44 weeks, the relative hazard for falls in the medication withdrawal group compared with the group taking their original medication was .34 (95% CI, .16-.74). The risk of falling for the exercise program group compared with those not receiving the exercise program was not significantly reduced.

CONCLUSIONS

Withdrawal of psychotropic medication significantly reduced the risk of falling, but permanent withdrawal is very difficult to achieve.

Association of angiotensinogen gene T235 variant with increased risk of coronary heart disease

Several genes, including some encoding components of the renin angiotensin system, are associated with the risk of cardiovascular diseases. There have been reports linking a homozygous deletion allele of the angiotensin converting enzyme (ACE) gene (DD) with an increased risk of myocardial infarction, and some variants of the angiotensinogen gene with an increased risk of hypertension. In a case-control study of a caucasian population from New Zealand, we examined the associations with coronary heart disease (CHD) of ACE DD and of a mis-sense mutation with methionine to threonine aminoacid substitution at codon 235 in the angiotensinogen gene (T235). We studied 422 patients (mean age 62 years, 81% male) with documented CHD (50% with myocardial infarction) and 406 controls without known CHD (frequency-matched to cases by age and sex). Risk factors for CHD were assessed by standard questionnaire, physical examination, and blood tests. Genomic DNA from leucocytes was analysed for various ACE and angiotensinogen alleles. Angiotensinogen T235 homozygotes were at significantly increased risk of CHD generally (odds ratio 1.7, 2 p = 0.008) and of myocardial infarction specifically (1.8, 2 p = 0.009). Adjustment for several risk factors increased the estimate of CHD risk associated with this allele to 2.6 (2 p < 0.001) and the estimate for myocardial infarction risk to 3.4 (2 p < 0.001). By contrast, there was no evidence of a significant increase in the risk of CHD or myocardial infarction among individuals with ACE DD. We conclude that the T235 polymorphism of the angiotensinogen gene is an independent risk factor, which carries an approximately two-fold increased risk of CHD. In this study, however, ACE DD was not associated with any detectable increase in CHD risk.

Helmets for preventing injury in motorcycle riders

BACKGROUND

Motorcycle crash victims form a high proportion of those killed or injured in road traffic crashes. Injuries to the head, following motorcycle crashes, are a common cause of severe morbidity and mortality. It seems intuitive that helmets should protect against head injuries but it has been argued that motorcycle helmet use decreases rider vision and increases neck injuries. This review will collate the current available evidence on helmets and their impact on mortality, and head, face and neck injuries following motorcycle crashes.

OBJECTIVES

To assess the effects of wearing a motorcycle helmet in reducing mortality and head and neck injury following motorcycle crashes.

SEARCH STRATEGY

We searched the Cochrane Injuries Group Specialised Register, Cochrane Central Register of Controlled Trials (The Cochrane Library issue 2, 2007), MEDLINE (up to April 2007), EMBASE (up to April week 16, 2007), CINAHL (January 1982 to February 2003), TRANSPORT (up to issue 12, 2006) (TRANSPORT combines the following databases: Transportation Research Information Services (TRIS) International Transport Research Documentation (ITRD) formerly International Road Research Documentation (IRRD), ATRI (Australian Transport Index) (1976 to Feb 2003), Science Citation Index were searched for relevant articles. Websites of traffic and road safety research bodies including government agencies were also searched. Reference lists from topic reviews, identified studies and bibliographies were examined for relevant articles.

SELECTION CRITERIA

We considered studies that investigated a population of motorcycle riders who had crashed, examining helmet use as an intervention and with outcomes that included one or more of the following: death, head, neck or facial injury. We included any studies that compared an intervention and control group. Therefore the following study designs were included: randomised controlled trials, non-randomised controlled trials, cohort, case-control and cross-sectional studies. Ecological and case series studies were excluded.

DATA COLLECTION AND ANALYSIS

Two authors independently screened reference lists for eligible articles. Two authors independently assessed articles for inclusion criteria. Data were abstracted by two independent authors using a standard abstraction form.

MAIN RESULTS

Sixty-one observational studies were selected of varying quality. Despite methodological differences there was a remarkable consistency in results, particularly for death and head injury outcomes. Motorcycle helmets were found to reduce the risk of death and head injury in motorcyclists who crashed. From four higher quality studies helmets were estimated to reduce the risk of death by 42% (OR 0.58, 95% CI 0.50 to 0.68) and from six higher quality studies helmets were estimated to reduce the risk of head injury by 69% (OR 0.31, 95% CI 0.25 to 0.38). Insufficient evidence was found to estimate the effect of motorcycle helmets compared with no helmet on facial or neck injuries. However, studies of poorer quality suggest that helmets have no effect on the risk of neck injuries and are protective for facial injury. There was insufficient evidence to demonstrate whether differences in helmet type confer more or less advantage in injury reduction.

AUTHORS' CONCLUSIONS

Motorcycle helmets reduce the risk of death and head injury in motorcycle riders who crash. Further well-conducted research is required to determine the effects of helmets and different helmet types on mortality, head, neck and facial injuries. However, the findings suggest that global efforts to reduce road traffic injuries may be facilitated by increasing helmet use by motorcyclists.

Vitamin D and respiratory health

Vitamin D is now known to be of physiological importance outside of bone health and calcium homeostasis, and there is mounting evidence that it plays a beneficial role in the prevention and/or treatment of a wide range of diseases. In this brief review the known effects of vitamin D on immune function are described in relation to respiratory health. Vitamin D appears capable of inhibiting pulmonary inflammatory responses while enhancing innate defence mechanisms against respiratory pathogens. Population-based studies showing an association between circulating vitamin D levels and lung function provide strong justification for randomized controlled clinical trials of vitamin D supplementation in patients with respiratory diseases to assess both efficacy and optimal dosage.

Visual impairment and risk of hip fracture

As part of a case-control study, the Auckland Hip Fracture Study (1991-1994), the authors examined associations between impaired vision and risk of hip fracture. Subjects (911 cases and 910 controls aged 60 years or older) completed a questionnaire and had vision measurements taken, including measurements of visual acuity and stereopsis (depth perception). Binocular visual acuity worse than 20/60 was statistically significantly associated with increased risk of hip fracture after adjustment for age, sex, proxy response, hours of activity per week, and height (odds ratio (OR) = 1.5; 95% confidence interval (CI): 1.1, 2.0), as was having poor vision (less than 20/100) in both eyes (OR = 2.4; 95% CI: 1.0, 6.1). Having no depth perception was associated with increased risk (OR = 6.0 95% CI: 3.2, 11.1), as were categories of decreasing stereopsis (trend p = 0.0001), self-reported poor vision (OR = 1.4; 95% CI: 1.0, 1.9), not wearing glasses at the time of the fall (OR = 1.2; 95% CI: 1.0, 1.6), and increasing time since the last eye examination (trend p = 0.03). The population attributable risk of hip fracture due to poor visual acuity or stereopsis was 40%. Visual factors are important fall-related factors which influence risk of hip fracture. Risk of hip fracture may be decreased by correcting refractive error, improving stereopsis, and administering regular eye examinations.

Sex-specific relevance of diabetes to occlusive vascular and other mortality: a collaborative meta-analysis of individual data from 980 793 adults from 68 prospective studies

BACKGROUND

Several studies have shown that diabetes confers a higher relative risk of vascular mortality among women than among men, but whether this increased relative risk in women exists across age groups and within defined levels of other risk factors is uncertain. We aimed to determine whether differences in established risk factors, such as blood pressure, BMI, smoking, and cholesterol, explain the higher relative risks of vascular mortality among women than among men.

METHODS

In our meta-analysis, we obtained individual participant-level data from studies included in the Prospective Studies Collaboration and the Asia Pacific Cohort Studies Collaboration that had obtained baseline information on age, sex, diabetes, total cholesterol, blood pressure, tobacco use, height, and weight. Data on causes of death were obtained from medical death certificates. We used Cox regression models to assess the relevance of diabetes (any type) to occlusive vascular mortality (ischaemic heart disease, ischaemic stroke, or other atherosclerotic deaths) by age, sex, and other major vascular risk factors, and to assess whether the associations of blood pressure, total cholesterol, and body-mass index (BMI) to occlusive vascular mortality are modified by diabetes.

RESULTS

Individual participant-level data were analysed from 980 793 adults. During 9·8 million person-years of follow-up, among participants aged between 35 and 89 years, 19 686 (25·6%) of 76 965 deaths were attributed to occlusive vascular disease. After controlling for major vascular risk factors, diabetes roughly doubled occlusive vascular mortality risk among men (death rate ratio [RR] 2·10, 95% CI 1·97-2·24) and tripled risk among women (3·00, 2·71-3·33; χ2 test for heterogeneity p<0·0001). For both sexes combined, the occlusive vascular death RRs were higher in younger individuals (aged 35-59 years: 2·60, 2·30-2·94) than in older individuals (aged 70-89 years: 2·01, 1·85-2·19; p=0·0001 for trend across age groups), and, across age groups, the death RRs were higher among women than among men. Therefore, women aged 35-59 years had the highest death RR across all age and sex groups (5·55, 4·15-7·44). However, since underlying confounder-adjusted occlusive vascular mortality rates at any age were higher in men than in women, the adjusted absolute excess occlusive vascular mortality associated with diabetes was similar for men and women. At ages 35-59 years, the excess absolute risk was 0·05% (95% CI 0·03-0·07) per year in women compared with 0·08% (0·05-0·10) per year in men; the corresponding excess at ages 70-89 years was 1·08% (0·84-1·32) per year in women and 0·91% (0·77-1·05) per year in men. Total cholesterol, blood pressure, and BMI each showed continuous log-linear associations with occlusive vascular mortality that were similar among individuals with and without diabetes across both sexes.

INTERPRETATION

Independent of other major vascular risk factors, diabetes substantially increased vascular risk in both men and women. Lifestyle changes to reduce smoking and obesity and use of cost-effective drugs that target major vascular risks (eg, statins and antihypertensive drugs) are important in both men and women with diabetes, but might not reduce the relative excess risk of occlusive vascular disease in women with diabetes, which remains unexplained.

FUNDING

UK Medical Research Council, British Heart Foundation, Cancer Research UK, European Union BIOMED programme, and National Institute on Aging (US National Institutes of Health).

The role of driver sleepiness in car crashes: a systematic review of epidemiological studies

To assess the available evidence for a causal role of driver sleepiness in car crashes or car crash injury, and to quantify the effect, a systematic review of the international literature was conducted. The review included all studies with a fatigue-related exposure measure, a crash or crash injury outcome measure and a comparison group, regardless of publication status, language or date of the study. Eighteen cross-sectional studies and one case-control study fulfilled the inclusion criteria. The fatigue-related exposures investigated in these studies were sleep disorders (n = 14), shift work (n = 2), sleep deprivation/fragmentation (n = 1), and excessive daytime sleepiness (n = 2). Only one study used an injury outcome measure. Studies were limited in their ability to establish a causal relationship by their design, by biases, and in many cases, by small sample sizes. The better quality cross-sectional studies were suggestive of a positive relationship between fatigue and crash risk, but could not provide reliable estimates of the strength of the association. The case-control study provided moderately strong evidence for an association between sleep apnoea and risk of driver injury, with an adjusted odds ratio of 7.2 (95% confidence interval 2.4-21.8). We conclude that the direct epidemiological evidence for a causal role of fatigue in car crashes is weak, but suggestive of an effect. To estimate the burden of injury due to fatigue-related crashes in the population, information is required from well-designed observational epidemiological studies about the prevalence of fatigue in the car driving population and the size of the risk this confers.

Human Melioidosis

The causative agent of melioidosis, Burkholderia pseudomallei, a tier 1 select agent, is endemic in Southeast Asia and northern Australia, with increased incidence associated with high levels of rainfall. Increasing reports of this condition have occurred worldwide, with estimates of up to 165,000 cases and 89,000 deaths per year. The ecological niche of the organism has yet to be clearly defined, although the organism is associated with soil and water. The culture of appropriate clinical material remains the mainstay of laboratory diagnosis. Identification is best done by phenotypic methods, although mass spectrometric methods have been described. Serology has a limited diagnostic role. Direct molecular and antigen detection methods have limited availability and sensitivity. Clinical presentations of melioidosis range from acute bacteremic pneumonia to disseminated visceral abscesses and localized infections. Transmission is by direct inoculation, inhalation, or ingestion. Risk factors for melioidosis include male sex, diabetes mellitus, alcohol abuse, and immunosuppression. The organism is well adapted to intracellular survival, with numerous virulence mechanisms. Immunity likely requires innate and adaptive responses. The principles of management of this condition are drainage and debridement of infected material and appropriate antimicrobial therapy. Global mortality rates vary between 9% and 70%. Research into vaccine development is ongoing.

Evidence that the acute behavioral and electrophysiological effects of bupropion (Wellbutrin) are mediated by a noradrenergic mechanism

Bupropion (BW 323U66) has been considered a dopaminergic antidepressant based on its ability to inhibit the uptake of dopamine (DA) somewhat more selectively than it inhibits uptake of norepinephrine (NE) or serotonin (5-HT). This report describes new evidence that bupropion selectively inhibits firing rates of NE cells in the locus coeruleus (LC) at doses significantly lower than those that inhibit activity of midbrain DA cells or dorsal raphe 5-HT cells. The IC50 dose (13 mg/kg i.p.) for inhibition of LC firing produced plasma concentrations that were not significantly different from those generated by the ED50 in the Porsolt test (10 mg/kg i.p.). The fourfold higher dose needed to inhibit DA cell firing (IC50 = 42 mg/kg i.p.) was similar to the dose associated with locomotor stimulation in freely moving rats. Bupropion did not change the firing rates of 5-HT cells in the dorsal raphe nucleus at any dose. In both in vitro and in vivo tests, the metabolite 306U73 (hydroxybupropion), a weak inhibitor of NE uptake, was approximately equipotent to bupropion with regard to inhibition of LC cells. Another metabolite, 494U73, had no effect on LC firing rates over a wide range of doses. Because of species variation in metabolism, 306U73 was not detected in plasma of rats after i.v. doses of bupropion that inhibited LC firing. Only trace amounts of 306U73 were detected after bupropion dosing for the Porsolt test. Pretreatment with reserpine markedly depleted catecholamines and reduced (by 30-fold) the potency of bupropion to inhibit LC firing.(ABSTRACT TRUNCATED AT 250 WORDS)

Circumstances of falls resulting in hip fractures among older people

OBJECTIVES

To describe the circumstances of falls resulting in hip fractures among older people and to determine whether the circumstances differ by gender, age, and residential status.

DESIGN

Cross-sectional study.

SETTING

Two hospitals in Auckland, New Zealand, in which all individuals aged 60 years or older with a fracture of the proximal femur are hospitalized.

PARTICIPANTS

A total of 911 individuals (97% response rate) were hospitalized with fractures of the proximal femur; 77% were women, 66% were aged 80 years or older, and 58% were living in private homes at the time of fracture.

MEASUREMENTS

Data were collected face-to-face by a trained interviewer using a standardized questionnaire.

RESULTS

Ninety-six percent of the fractures were associated with a fall, with fewer that 2% of subjects reporting that their fractures occurred spontaneously before a fall. Sixteen percent of fractures were associated with an acute medical or physical condition. Although 85% of the fractures involving a fall occurred at home, only about 25% of these were associated with an environmental hazard, and only a proportion of these were likely to have been amenable to modification. The circumstances of falls differed significantly by age and residential status.

CONCLUSION

Strategies aimed at preventing fall-related hip fractures among the old old and among institutionalized individuals should focus primarily on the modification of intrinsic factors. Modification of environmental hazards has the greatest potential for prevention among the young old and those living in private homes.

Effect of environmental factors on risk of injury of child pedestrians by motor vehicles: a case-control study

OBJECTIVE

To identify and assess contribution of environmental risk factors for injury of child pedestrians by motor vehicles.

DESIGN

Community based case-control study. Environmental characteristics of sites of child pedestrian injury were compared with the environmental characteristics of selected comparison sites. Each comparison site was the same distance and direction from home of control child as was the injury site from home or relevant case child. Two control sites were selected for each injury site.

SETTING

Auckland region of New Zealand.

SUBJECTS

Cases were 190 child pedestrians aged < 15 who were killed or hospitalised after collision with a motor vehicle on a public road during two years and two months. Controls were 380 children randomly sampled from population and frequency matched for age and sex.

MAIN OUTCOME MEASURE

Traffic volume and speed and level of parking on curbs at injury sites and comparison sites.

RESULTS

Risk of injury of child pedestrians was strongly associated with traffic volume: risk of injury at sites with highest traffic volumes was 14 times greater than that at least busy sites (odds ratio 14.30; 95% confidence interval 6.98 to 29.20), and risk increased with increasing traffic volume. High density of curb parking was also associated with increased risk (odds ratio 8.12; 3.32 to 19.90). Risk was increased at sites with mean speeds over 40 km/h (odds ratio 2.68; 1.26 to 5.69), although risk did not increase further with increasing speed.

CONCLUSION

Reducing traffic volume in urban areas could significantly reduce rates of child pedestrian injury. Restricting curb parking may also be effective.

Alcohol consumption and the risk of alcohol related cirrhosis in women

The risks in women of cirrhosis with a likely primary alcohol aetiology were estimated for various levels of alcohol consumption in a case-control study. Data were obtained from 41 women with a first diagnosis of cirrhosis who had no evidence of non-alcohol-related cirrhosis; three matched controls were interviewed for each case. Significant increases in the risk of cirrhosis were detected at levels of consumption between 41 and 60 g daily; above this level a dose-response relation was observed. The risk of cirrhosis did not appear to be influenced by other nutritional factors or history of liver disease or use of hepatotoxic drugs. One per cent of Australian women consume more than 40 g alcohol daily, yet more than 90% of women identified with cirrhosis consumed alcohol at this level. Preventive interventions to reduce alcohol consumption in the small group of women who consume more than 40 g daily have the potential to reduce substantially the incidence of alcohol related cirrhosis.

Risk factors for injuries and other health problems sustained in a marathon

OBJECTIVES

To identify risk factors for injuries and other health problems occurring during or immediately after participation in a marathon.

METHODS

A prospective cohort study was undertaken of participants in the 1993 Auckland Citibank marathon. Demographic data, information on running experience, training and injuries, and information on other lifestyle factors were obtained from participants before the race using an interviewer-administered questionnaire. Information on injuries and other health problems sustained during or immediately after the marathon were obtained by a self administered questionnaire. Logistic regression analyses were undertaken to identify significant risk factors for health problems.

RESULTS

This study, one of only a few controlled epidemiological studies that have been undertaken of running injuries, has identified a number of risk factors for injuries and other health problems sustained in a marathon. Men were at increased risk of hamstring and calf problems, whereas women were at increased risk of hip problems. Participation in a marathon for the first time, participation in other sports, illness in the two weeks before the marathon, current use of medication, and drinking alcohol once a month or more, were associated with increased self reported risks of problems. While increased training seemed to increase the risk of front thigh and hamstring problems, it may decrease the risk of knee problems. There are significant but complex relations between age and risk of injury or health problem.

CONCLUSIONS

This study has identified certain high risk subjects and risk factors for injuries and other health problems sustained in a marathon. In particular, subjects who have recently been unwell or are taking medication should weigh up carefully the pros and cons of participating.

Effects of folate supplementation on two provisional molecular markers of colon cancer: a prospective, randomized trial

OBJECTIVES

Dietary folate intake is inversely associated with the risk of colorectal cancer. This study investigated the effect of folate supplementation on genomic DNA methylation and DNA strand breaks in exons 5-8 of the p53 gene of the colonic mucosa, two provisional biomarkers of colon cancer.

METHODS

Twenty subjects with adenomas were randomized to receive either folate (5 mg/day) or placebo for 1 yr after polypectomy. At baseline, 6 months and 1 yr, systemic and colonic measures of folate status were determined, as were the biomarkers mentioned earlier.

RESULTS

Folate supplementation increased serum, red blood cell and colonic mucosal folate concentrations (p < 0.02). Folate supplementation also increased the extent of genomic DNA methylation at 6 months and 1 yr (p = 0.001), whereas placebo administration was associated with an increase in the extent of genomic DNA methylation only at 1 yr. Similarly, folate supplementation decreased the extent of p53 strand breaks in exons 5-8 at 6 months and 1 yr (p < 0.02), whereas placebo administration was associated with a decrease in the extent of p53 strand breaks only at 1 yr.

CONCLUSIONS

Both of these provisional biomarkers of colon cancer underwent accelerated improvement at 6 months with folate supplementation. However, these markers also improved with placebo at 1 yr. Therefore, potential confounding factors that seem to modulate these biomarkers need to be identified and corrected in order for these markers to serve as suitable surrogate endpoints in folate chemoprevention trials.

Increasing age and experience: are both protective against motorcycle injury? A case-control study

OBJECTIVES

To assess the associations between age, experience, and motorcycle injury.

SETTING

Motorcycle riding on non-residential roads between 6 am and midnight over a three year period from February 1993 in Auckland, New Zealand.

METHODS

A population based case-control study was conducted. Cases were 490 motorcycle drivers involved in a crash and controls were 1518 drivers identified at random roadside surveys. Crash involvement was defined in terms of a motorcycle crash resulting in either a driver or pillion passenger being killed, hospitalised, or presenting to a public hospital emergency department with an injury severity score > OR =5.

RESULTS

There was a strong and consistent relationship between increasing driver age and decreasing risk of moderate to fatal injury. In multivariate analyses, drivers older than 25 years had more than 50% lower risk than those aged from 15-19 years (odds ratio (OR) 0.46; 95% confidence interval (CI) 0.26 to 0.81). In univariate analyses, a protective effect from riding more than five years compared with less than two years was observed. However, this protection was not sustained when driver age and other potential confounding variables were included in the analyses. Familiarity with the specific motorcycle was the only experience measure associated with a strong protective effect (OR (> OR =10,000 km experience) 0.52; 95% Ci 0.35 to 0.79) in multivariate analyses.

CONCLUSIONS

Current licensing regulations should continue to emphasise the importance of increased age and might consider restrictions that favour experience with a specific motorcycle.

Neuroprotective properties of the novel antiepileptic lamotrigine in a gerbil model of global cerebral ischemia

BACKGROUND AND PURPOSE

Elevated glutamate levels are thought to be a primary cause of neuronal death after global cerebral ischemia. The purpose of this study was to investigate the potential neuroprotective effects of lamotrigine, a novel antiepileptic drug that inhibits the release of glutamate in vitro, with both behavioral and histological measures of global ischemia in gerbils.

METHODS

The common carotid arteries of gerbils were occluded for either 5, 10, or 15 minutes. Twenty-one days after reperfusion, gerbils were tested for impairments in a spatial memory task (Morris water maze). After water maze testing the animals were killed, and damage to hippocampal pyramidal cells was assessed. The effect of lamotrigine on the behavioral and histological outcome of either 5 or 15 minutes of global ischemia was evaluated.

RESULTS

Bilateral occlusion of the common carotid arteries for 5 minutes resulted in severe degeneration of hippocampal CA1 and CA2 pyramidal cells. Lamotrigine significantly prevented loss of hippocampal CA1 neurons when administered acutely (100 mg/kg PO) immediately after reperfusion or when administered in two equal doses of 30 or 50 mg/kg 2 hours before and immediately after reperfusion. Gerbils subjected to 5 minutes of ischemic insult were not impaired in their ability to solve a spatial memory task 21 days after cerebral ischemia. However, gerbils subjected to 10 and 15 minutes of carotid artery occlusion showed significant impairment in their ability to solve a water maze task. Lamotrigine significantly protected against the cognitive deficits associated with 15 minutes of cerebral ischemia. Histologically, increased durations of cerebral ischemia resulted in a progressive loss of CA1, CA2, and CA3 pyramidal cells. Lamotrigine completely protected gerbils exposed to 15 minutes of cerebral ischemia against CA3 cell loss and greatly reduced damage to the CA1 and CA2 cell tracts of the hippocampus. Lamotrigine also reduced the mortality associated with 15 minutes of ischemia.

CONCLUSIONS

Lamotrigine had neuroprotective effects in a gerbil model of global cerebral ischemia. Lamotrigine protected gerbils against behavioral deficits resulting from 15 minutes of carotid occlusion and also prevented histological damage resulting from 5 and 15 minutes of global cerebral ischemia.

The risks of hip fracture in older people from private homes and institutions

This study aimed to determine whether the incidence of hip fracture is greater among those living in institutions compared with those living in private homes. Over two and a half years of surveillance, 1832 hip fractures were identified, of which 58% were sustained by those living in private homes and 42% by those living in institutions. The risks of hip fracture, unadjusted for age and sex, were 10.5 times greater for those living in institutions compared with those living in private homes. After adjusting for age and sex, these greatly increased risks were maintained, although for both men and women the risks decreased with age, such that at ages over 90 years the risks were not significantly different. Given these findings, hip fracture prevention strategies that focus particularly on individuals within institutions are highly commended.

Fifteen-year experience with the mitral Carpentier-Edwards PERIMOUNT pericardial bioprosthesis

BACKGROUND

This multicenter study concerning the mitral PERIMOUNT valve previously reported clinical results at 12 years; this report updates the performance to 15 years postoperatively.

METHODS

The 435 patients (mean age 60.7+/-11.6 years; 41.1% male) underwent implantation with the PERIMOUNT valve between 1984 and 1989 at seven institutions. Follow-up was complete for 96.1% of the cohort. The mean follow-up was 8.1+/-4.4 years (range 0 to 15.4 years) for a total of 3492 patient-years.

RESULTS

There were 34 (7.8%) operative deaths, one (0.2%) valve related. The late mortality rate was 5.3%/patient-year (2.2%/patient-year valve related). At 14 years, the overall actuarial survival rate was 37.1%+/-3.3% (63.1%+/-4.4% valve related). Actuarial freedom from complications at 14 years was as follows: thromboembolism, 83.8%+/-3.2% (1.1%/patient-year); hemorrhage, 86.6%+/-3.2% (1.1%/patient-year); and explant due to structural valve deterioration (SVD), 68.8%+/-4.7%. Actual freedom from explant due to SVD was 83.4%+/-2.3%. Rates of structural failure decreased with increasing age at implant.

CONCLUSIONS

The Carpentier-Edwards PERIMOUNT Pericardial Bioprosthesis is a reliable choice for a tissue valve in the mitral position, especially in patients more than 60 years of age.

Residential status and risk of hip fracture

OBJECTIVE

to examine the association between residential status and risk of hip fracture in older people.

DESIGN

population-based case-control study.

SETTING

Auckland, New Zealand.

SUBJECTS

a random sample of all individuals > or = 60 years, hospitalized with a fracture of the proximal femur between July 1991 and February 1994. Controls were age and gender frequency-matched to the cases, randomly selected from a random sample of general practitioners.

MAIN OUTCOME MEASURES

radiographically-confirmed fracture of the proximal femur. Fractures sustained as a result of major trauma, such as in a motor vehicle crash, and those associated with pre-existing pathological conditions were excluded.

RESULTS

individuals living in institutions were almost four times more likely to sustain a hip fracture [age- and gender-adjusted odds ratio (OR)=3.8; 95% confidence interval (CI): 3.0-4.8] than those living in private homes. After adjustment for potential confounding factors, the risk of hip fracture associated with living in an institution remained significantly increased (P< 0.0001), although the magnitude of the risk was somewhat diminished (OR=2.2; 95% (CI: 1.5-3.5).

CONCLUSIONS

living in an institution is associated with an increased risk of hip fracture in older people. Specific factors that place these individuals at increased risk need to be identified, in order to develop intervention strategies.

Comparison and standardisation of serological methods for the diagnosis of Neospora caninum infection in bovines

Various existing serological tests were compared with a standard panel of 523 sera in a multicentred study across Europe. Well characterised sera from animals that were experimentally or naturally infected with Neospora caninum as well as sera from cattle deemed uninfected with N. caninum were provided by the participants of the study and analysed in several commercial (CHEKIT Dr. Bommeli/Intervet, CIVTEST BOVIS NEOSPORA Hipra, Cypress Diagnostics C.V., Herd Check IDEXX, Mastazyme MAST Diagnostics, P38-ELISA Animal Welfare and Food Safety GmbH (AFOSA)) as well as in-house assays (five ELISAs and one IFAT). Most tests showed a high level of agreement in the interpretation of the test results (positive or negative). A further distinct increase in agreement between tests was obtained after the application of standardised cut-offs offered by a two-graph receiver operating characteristic analysis. This procedure allows a standardised interpretation of results obtained with different tests used in independent, parallel seroepidemiological studies.

Burkholderia pseudomallei virulence: definition, stability and association with clonality

Clinical presentations of melioidosis, caused by Burkholderia pseudomallei are protean, but the mechanisms underlying development of the different forms of disease remain poorly understood. In murine melioidosis, the level of virulence of B. pseudomallei is important in disease pathogenesis and progression. In this study, we used B. pseudomallei-susceptible BALB/c mice to determine the virulence of a library of clinical and environmental B. pseudomallei isolates from Australia and Papua New Guinea. Among 42 non-arabinose-assimilating (ara(-)) isolates, LD(50) ranged from 10 to > 10(6) CFU. There were numerous correlations between virulence and disease presentation in patients; however, this was not a consistent observation. Virulence did not correlate with isolate origin (i.e. clinical vs environmental), since numerous ara(-) environmental isolates were highly virulent. The least virulent isolate was a soil isolate from Papua New Guinea, which was arabinose assimilating (ara(+)). Stability of B. pseudomallei virulence was investigated by in vivo passage of isolates through mice and repetitive in vitro subculture. Virulence increased following in vivo exposure in only one of eight isolates tested. In vitro subculture on ferric citrate-containing medium caused attenuation of virulence, and this correlated with changes in colony morphology. Pulsed-field gel electrophoresis and randomly amplified polymorphic DNA typing demonstrated that selected epidemiologically related isolates that had variable clinical outcomes and different in vivo virulence were clonal strains. No molecular changes were observed in isolates after in vivo or in vitro exposure despite changes in virulence. These results indicate that virulence of selected B. pseudomallei isolates is variable, being dependent on factors such as iron bioavailability. They also support the importance of other variables such as inoculum size and host risk factors in determining the clinical severity of melioidosis.

Declines in physical functioning attributable to hip fracture among older people: a follow-up study of case-control participants

PURPOSE

To identify declines in physical functioning, directly attributable to the effects of hip fracture.

METHODS

A follow-up study of participants in a case-control study was conducted in Auckland, New Zealand, between 1993 and 1996. Nine hundred and eleven randomly selected older people with a hip fracture at the time of the initial interview (cases) and 910 randomly selected older people, without hip fracture (controls), were invited to participate in the study. Two year changes in physical functioning, defined in terms of self-reported mobility, functional dependence and physical activity were examined.

RESULTS

Data from the survivors (572 cases and 756 controls) showed that, after controlling for pre-existing chronic medical conditions and disabilities, cases were 4.2 times more likely than controls to be community immobile (95% confidence interval (CI) 2.8-6.2, p < 0.001) and 2.6 times more likely to be functionally dependent (95% CI 1.7-4.1, p < 0.001). Cases were also spending less hours per day on their feet (2.9) compared with controls (3.5) (F1,1211 = 55.7, p < 0.001).

CONCLUSIONS

Hip fractures are associated with dramatic declines in physical functioning at two years, independent of the effects of increasing age, pre-existing medical conditions and disabilities.

Structural valve deterioration in mitral replacement surgery: comparison of Carpentier-Edwards supra-annular porcine and perimount pericardial bioprostheses

BACKGROUND

Bioprostheses preserved with glutaraldehyde, both porcine and pericardial, have been available as second-generation prostheses for valve replacement surgery. The performance with regard to structural valve deterioration with the Carpentier-Edwards supra-annular (CE-SAV) porcine bioprosthesis and the Carpentier-Edwards Perimount (CE-P) pericardial bioprosthesis (Baxter Healthcare Corp, Edwards Division, Santa Ana, Calif) was evaluated to determine whether there was a difference in mitral valve replacement.

METHODS

The CE-SAV bioprosthesis was implanted in 1266 overall mitral valve replacements (isolated mitral, 1066; mitral in multiple, 200) and the CE-P bioprosthesis in 429 overall mitral valve replacements (isolated mitral, 328; mitral in multiple, 101). The mean age of the CE-SAV population was 64.2 +/- 12.2 years and that of the CE-P population, 60.7 +/- 11.7 years (P =.0001). For the study, structural valve deterioration was diagnosed at reoperation for explantation.

RESULTS

The freedom from structural valve deterioration was evaluated to 10 years, and the freedom rates reported are at 10 years. For the overall mitral valve replacement groups, the actuarial freedom from deterioration was significant (P =.0001): CE-P > CE-SAV for 40 years or younger, 80% versus 60%; 41 to 50 years, 91% versus 61%; 51 to 60 years, 84% versus 69%; 61 to 70 years, 95% versus 75%. The older than 70-year group was 100% versus 92% (no significant difference). The actual freedom from structural valve deterioration also demonstrated the same pattern at 10 years: 40 years or younger, CE-P 82% versus CE-SAV 68%; 41 to 50 years, 92% versus 70%; 51 to 60 years, 90% versus 80%; 61 to 70 years, 97% versus 88%; and older than 70 years, 100% versus 97%. The independent risk factors of structural valve deterioration for the overall mitral valve replacement group were age and age groups and prosthesis type (CE-SAV > CE-P). The prosthesis type either in isolated replacement or in multiple replacement was not predictive of structural valve deterioration. The pathology of structural valve deterioration was different: 70% of CE-P failures were due to calcification and 57% of CE-SAV failures were due to combined calcification and leaflet tear.

CONCLUSION

The actuarial and actual freedom from structural valve deterioration, diagnosed at reoperation, is greater at 10 years for CE-P than for CE-SAV bioprostheses. The mode of failure is different, and the cause remains obscure. Long-term evaluation is recommended, because the different modes of failure may alter the clinical performance by 15 and 20 years.