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PubMed2005

Urban-rural differences in motor vehicle crash fatality and hospitalization rates among children and youth.

This population-based study examined motor vehicle crash hospitalization rates and death rates among children and youth in rural and urban areas of the province of Alberta, Canada. Using police report data (1997-2002, inclusive), average annual motor vehicle crash hospitalization and death rates among those 0-19 years of age were calculated for rural and urban regions. Across all age and sex strata examined, both the hospitalization and the fatality rates were significantly higher in rural compared with urban regions. After adjusting for age, sex and calendar year, the relative risk of a motor vehicle crash hospitalization (rural versus urban) was 3.0 (95% CI: 2.8, 3.2). After adjusting for age, sex and calendar year, the relative risk of a motor vehicle crash fatality was 5.4 (95% CI: 4.2, 6.9). Motor vehicle crash injury hospitalization and fatality rates among children and youth in the province of Alberta are considerably higher in rural areas compared with urban areas. There is a need to identify social, demographic and environmental driving hazards associated with the rural environment.

Accidents, Traffic↗
PubMed1989

Sampling stratospheric aerosols with impactors.

Derivation of statistically significant size distributions from impactor samples of rarefied stratospheric aerosols imposes difficult sampling constraints on collector design. It is shown that is is necessary to design impactors of different size for each range of aerosol size collected as as to obtain acceptable levels of uncertainty with a reasonable amount of data reduction.

Aerosols↗
PubMed2001

Per capita alcohol consumption and ischaemic heart disease mortality.

AIM: To test the hypothesis that alcohol consumption is inversely related to ischaemic heart disease (IHD) mortality at the population level. Most individual-level studies find a reduced risk of IHD with a moderate level of alcohol consumption, but it is as yet unknown whether this association also exists at the aggregate level. MEASUREMENTS: The study period was approximately 1950 to 1995; 14 EU countries and Norway were included. Time series analyses on different data were utilized, and age-standardized IHD mortality for men and women in the age groups 30-44, 45-59, 60-74 and 30-74 years was measured. The effects of alcohol (sales per capita) were controlled for a weighted lag of per capita sales of cigarettes. FINDINGS: There was a random distribution of insignificant negative and positive alcohol effect estimates. A slight indication of a cardioprotective effect of alcohol among 30- to 44-year-old women in high consumption countries could be observed (significant for Italy). Mean alcohol effect estimates were nearly exactly zero (absent alcohol effect) among men and weakly positive among women. Because changes in cigarette consumption were often significantly and positively related to subsequent changes in IHD mortality, poor validity in the IHD time series cannot explain the unsystematic findings. Including a 6-year weighted lag of alcohol consumption changed the weak positive effect among women to an absent alcohol effect. A brief analysis of abstinence rates indicated no particular relationship to IHD mortality. CONCLUSION: The alleged cardioprotective alcohol effect is absent at the population level, and great caution should be taken concerning alcohol policies for cardioprotective purposes.

Adult↗
PubMedDate not supplied

Lichen striatus.

Lichen striatus is a self-limiting inflammatory condition of unknown etiology in which the lesions follow the lines of Blaschko. We report a series of 61 cases of this condition in children, describing the clinical features, age distribution, and season of onset. The preponderance of cases in the preschool-age group and onset in the spring and summer months support the hypothesis of an environmental agent, possibly an infection, in the etiology of the condition.

Age Distribution↗
PubMed2005

Comparison of fatalities from work related motor vehicle traffic incidents in Australia, New Zealand, and the United States.

OBJECTIVE: To compare the extent and characteristics of motor vehicle traffic incidents on public roads resulting in fatal occupational injuries in Australia, New Zealand (NZ), and the United States (US). DESIGN AND SETTING: Information came from separate data sources in Australia (1989--92), NZ (1985--98), and the US (1989--92). METHODS: Using data systems based on vital records, distributions and rates of fatal injuries resulting from motor vehicle traffic incidents were compared for the three countries. Common inclusion criteria and occupation and industry classifications were used to maximize comparability. RESULTS: Motor vehicle traffic incident related deaths accounted for 16% (NZ), 22% (US), and 31% (Australia) of all work related deaths during the years covered by the studies. Australia had a considerably higher crude rate (1.69 deaths/100,000 person years; 95% confidence interval (95% CI) 1.54 to 1.83) compared with both NZ (0.99; 95% CI 0.85 to 1.12) and the US (0.92; 95% CI 0.89 to 0.94). Industry distribution differences accounted for only a small proportion of this variation in rates. Case selection issues may have accounted for some of the remainder, particularly in NZ. In all three countries, male workers, older workers, and truck drivers were at higher risk. CONCLUSIONS: Motor vehicle traffic incidents are an important cause of work related death of workers in Australia, NZ, and the US. The absolute rates appear to differ between the three countries, but most of the incident characteristics were similar. Lack of detailed data and inconsistencies between the data sets limit the extent to which more in-depth comparisons could be made.

Accidents, Occupational↗
PubMed2002

Temporal change in risk of metachronous contralateral renal cell carcinoma: influence of tumor characteristics and demographic factors.

PURPOSE: To determine the relative risk (RR) of developing a metachronous contralateral renal tumor after an initial diagnosis of renal cell carcinoma (RCC), with stratification by renal tumor characteristics, demographic factors, and follow-up duration, in order to develop an improved risk-based surveillance strategy. PATIENTS AND METHODS: The 1973 to 1997 Surveillance, Epidemiology, and End Results database was used to determine the observed and expected number of metachronous contralateral renal tumors developing after an initial diagnosis of RCC. RESULTS: A total of 43,483 patients had a first diagnosis of RCC. Contralateral RCC developed subsequently in 155 (0.4%) of 40,049 patients with follow-up who had no synchronous diagnosis of RCC, with 10.81 expected cases (RR, 14.3; 95% CI, 12.2 to 16.8). The respective RRs (and 95% CIs) for contralateral RCC for white men and women were 16.0 (11.1 to 22.3) and 13.7 (7.7 to 22.6) at less than 2 years, 8.8 (5.0 to 14.3) and 10.5 (5.0 to 19.3) at 2 to 5 years, 13.5 (8.1 to 21.0) and 5.1 (1.4 to 13.2) at 5 to 10 years, and 13.0 (6.2 to 23.9) and 13.7 (5.0 to 29.9) at > or = 10 years, respectively. The RRs were significantly higher in black compared with white men for the first 5 years, with the RRs (and 95% CIs) in the former group of 95.3 (58.2 to 146.7) at less than 2 years and 41.9 (16.8 to 86.3) at 2 to 5 years. CONCLUSION: The incidence of metachronous contralateral RCC is stable on long-term follow-up, suggesting that surveillance of the contralateral kidney should remain rigorous on extended follow-up. Black men are at a significantly higher risk of developing contralateral RCC in the first 5 years of follow-up.

Adult↗
PubMedDate not supplied

Sleep related vehicle accidents on Italian highways.

Sleepiness has been identified as a significant risk factor for vehicle accidents, and specific surveys are needed for Italy. The aim of this study was to assess incidence and characteristics of sleep-related vehicle-crashes on Italian highways. The database of the Italian National Institute of Statistics (1993-1997) was the source for the survey (50859 accidents with 1632 (3.2%) ascribed to sleep by the police). The distribution of accidents was evaluated by means of the analysis of variance considering the year, the day of the week, the age and the time of day and their interactions as main factors. The relative risk of sleep-related accidents was also evaluated with reference to the relative traffic density as estimated by the Italian Highways Society. The counts of sleep-related accidents, and even more the relative risk, revealed the presence of peaks and troughs in zones at a higher level of sleepiness and alertness respectively. Death of the driver occurred in 11.4% of sleep related accidents versus 5.6% in general accidents. The great majority of sleep-related accidents occurred to drivers under 35 (61.4%) mainly during the night with an increasing trend in the yearly number of sleep-related accidents, especially on weekends. Therefore sleepiness appears a remarkable risk factor and, in our opinion, its incidence as sole or contributory cause of accidents on Italian highways is still underestimated.

Accidents, Traffic↗
PubMed1995

Assessment of postoperative pulmonary embolism as a measure of patient care.

Hospitals presenting voluntarily for accreditation survey during 1993 submitted data on pulmonary embolism to the Australian Council on Health Care Standard (ACHS) Care Evaluation Program (CEP) as a part of their medical quality activities. The data were stratified by hospital type and bed-size, and compared to the provisional threshold of 1%. The mean duration of data collection was 24 weeks (range 8-74 weeks). Of hospitals with bed-size 1-50, 77% observed a zero pulmonary embolism rate. Hospitals with zero and non-zero pulmonary embolism rates were significantly different with respect to bed-size (P = 0.001). The rarity of pulmonary embolism and lack of prospective continuous monitoring poses considerable problems in interpretation of aggregate rates. Hospitals with a high patient throughout should continuously monitor their pulmonary embolism data to achieve a large denominator. For smaller hospitals with a low performance of major operations, collection of data on this clinical indicator is unlikely to be useful as a measure of quality of care.

Accreditation↗
PubMed1995

Recruitment-driven, spatially discontinuous communities: a null model for transferred patterns in target communities of intestinal helminths.

Populations and therefore communities of intestinal helminths of vertebrates are fueled by recruitment of new individuals from outside the host. The source of new individuals is often an intermediate host that harbors several infective propagules of 1 or more species. Hence these source communities are transmitted in packets of infective propagules to target communities in definitive hosts. Packets not only provide recruits to target communities, but, because a packet of propagules possesses its own structure, it may also transmit structure to the target community. We use this system to examine the contribution that structure in the source pool of propagules makes to the structure of recruitment-driven target populations and communities. By treating the dynamics of such target populations and communities as immigration-death processes, we conclude: (1) Unlike a birth-driven population a recruitment-driven target population will grow to an asymptotic limit even in the absence of density-dependent processes or reaching carrying capacity; (2) the frequency distribution of the number of recruits entering target populations will determine the frequency distribution of adults in target populations; (3) interspecific associations among species in the source community will be transmitted to target communities, but the magnitude of the transmitted associations will depend upon the relative survival rates of the species; and (4) for associations of equal magnitude in a source community, the magnitude of a transferred negative association will be less than the magnitude of a positive association in a target community. Two examples of source communities in salt marsh crabs reveal that source infracommunities exist with the hypothesized structure. Further, the source helminth communities display a greater number of positive than negative interspecific associations. The inequity in transfer and the existence of a greater proportion of positive associations in source communities may explain the widespread occurrence of excess positive associations that has been noted in recruitment-driven communities.

Animals↗
PubMed1996

A model of stochastic activity of neurone in some types of Gaussian input processes.

A new approach to computer modelling of neuronal stochastic activity is described. The output dynamic activity which depends on the types and the number of input synapses, weights of the synaptic efficacy, the absolute refractory phase duration and threshold level is evaluated on this model in some types of Gaussian input processes. The behaviour of this model for one excitatory and one inhibitory synapse is described in dependence on the changes of excitation weight. The neuronal behaviour presented depends on the number of interspike intervals and the excitation weight and interspike interval density distribution. A novel concept of the e-curve is being introduced, which shows the dependence of the number of output interspike intervals on the weight of excitation on a stable inhibition level, the absolute refractory phase value and the threshold level. The properties of e-curves are discussed. Furthermore, examples of transformations of input stochastic processes are mentioned from the aspect of density distribution changes of interspike intervals.

Computer Simulation↗
PubMed2000

Invasive pneumococcal infection in Baltimore, Md: implications for immunization policy.

BACKGROUND: Streptococcus pneumoniae is a leading cause of infectious morbidity and mortality. Although blacks are known to have a higher incidence of invasive pneumococcal infection than whites, detailed analyses of these differences and their implications for vaccine prevention have not been reported. OBJECTIVE: To describe the epidemiological characteristics of invasive pneumococcal infection in Baltimore, Md, and its implications for immunization policy. METHODS: Analysis of active, laboratory-based surveillance during 1995 and 1996 among residents of the Baltimore metropolitan area. RESULTS: Of 1412 cases, 615 patients (43.6%) were classified as white and 766 (54.2%) as black. The annual incidence of invasive pneumococcal infection among white and black residents of the Baltimore metropolitan area was 17.8 and 59.2 per 100000 population, respectively (P<.01). Among patients aged 18 years and older, the median age of blacks with invasive pneumococcal infections was 27 years younger than that of whites (P<.01). Among males 40 to 49 years old, blacks had a 12-fold higher average incidence than whites (average incidence, 114.5 and 9.3, respectively; P<.01). By the age of 65 years, 83.8% of cases had occurred in black adults, as compared with 43.8% in white adults (P<.01). In a regression model, age, black race, male sex, low median family income, and county prevalence of acquired immunodeficiency syndrome were each independently associated with a higher incidence of pneumococcal infection. CONCLUSIONS: Young urban black adults in the Baltimore metropolitan area have a dramatically higher incidence of invasive pneumococcal infection than whites. The vast majority of cases of invasive pneumococcal infection in blacks occur before age 65 years. Current immunization efforts have not addressed the high incidence of pneumococcal infection in this population.

Adult↗
PubMed2005

Choice of exposure scores for categorical regression in meta-analysis: a case study of a common problem.

OBJECTIVE: Reporting categorical relative risk estimates for a series of exposure levels versus a common reference category is a widespread practice. In meta-analysis, categorical regression estimates a dose-response trend from such results. This method requires the assignment of a single score to each exposure category. We examined how closely meta-analytical categorical regression approximates the results of analysis based on the individual-level continuous exposure. METHODS: The analysis included five studies on tea intake and outcomes related to colorectal cancer. In addition, we derived categorical mean and median values from published distributions of tea consumption in similar populations to assign scores to the categories of tea intake when possible. We examined whether these derived mean and median values well approximate the individual-level results. RESULTS: In meta-analytical categorical regression, using the midrange scores approximated the individual-level continuous analyses reasonably well, if the value assigned to the uppermost, open-ended category was at least as high as the lower bound plus the width of the second-highest category. Categorical mean values derived from the published distributions of regular tea (in the US) and green tea (in Japan) well approximated the slope obtained from individual-level analysis. CONCLUSION: Publication of both the categorical and the continuous estimates of effect in primary studies, with their standard errors, can enhance the quality of meta-analysis, as well as providing intrinsically valuable information on dose-response.

Age Distribution↗
PubMed2004

The epidemiology of self-reported diarrhea in operations Iraqi freedom and enduring freedom.

Diarrhea remains a potential cause of compromised military effectiveness. To assess diarrhea rates and mission impact in operations in Iraq and Afghanistan, a survey was administered to soldiers participating in the "Rest and Recuperation" program in Doha, Qatar. Between October and December 2003, 2,389 volunteers completed a questionnaire designed to assess the occurrence and impact of diarrhea. The median length of deployment was 7.2 months, 70% reported at least one episode, and 56% had multiple episodes of diarrhea. Overall, 43% reported decreased job performance for a median of 2 days, and 17% reported being on bed rest for a median of 2 days. While this survey showed high rates of diarrhea associated with decreased operational effectiveness, the results are consistent with prior military operations in this region. Further research is needed to develop better methods for illness prevention and its minimization on operational impact.

Adult↗
PubMed1993

Heterogeneity in patterns of malarial oocyst infections in the mosquito vector.

Oocyst prevalence and intensity have been recorded in 349 laboratory infections of Anopheles stephensi with Plasmodium berghei. Intensity and prevalence of infection are shown to be predictably related. The structure and heterogeneity in the infections has been analysed with the objective of describing the biological mechanisms by which the observed negative binomial oocyst distributions are generated. The analysis has revealed that the most likely processes lie within the population dynamic events of malaria within the mosquito, namely gametogenesis, fertilization and mortality. The distribution is similar in all Plasmodium-mosquito combinations examined so far, whether they are of laboratory (P. gallinaceum in Aedes aegypti) or field (P. vivax in An. albimanus and P. falciparum in An. gambiae s.l. and An. funestus) origin. Further we conclude that there is competition between parasites in the vector. Oocyst frequency distribution analysis shows that under natural conditions of transmission intensity, and even under the best laboratory conditions, significant numbers (> 10%) of fully susceptible mosquitoes will not be infected under conditions where the mean infection is as high as 250 oocysts. Failure to infect is not therefore an absolute indicator of refractoriness. In assessing transmission data it is shown that sample sizes should not be less than 50, and ideally 100 mosquitoes, if reliable data are to be obtained. In field it is suggested that difficulties in determining the low natural intensity of oocyst infections indicate that prevalence estimates are a useful and accessible parameter to measure.(ABSTRACT TRUNCATED AT 250 WORDS)

Aedes↗
PubMed1998

Age-related cataract and place of birth.

Cataract patient data from 13 Australian practitioners were analysed in order to compare the distribution of seven principal types of cataract in relation to gender, age and place of birth. Relative odds ratios were calculated for age-matched pairs of three identifiable ethnic groups and each type of cataract. The number of statistically significant relative odds ratios far exceeds the expectation due to chance. The results suggest a relatively greater risk for cortical cataract amongst younger when compared with older groups. In contrast, the relative odds ratios for nuclear cataract, independently of age, were consistently greater than unity when Australians or Northern Europeans were compared with Southern Europeans. There was no gender-based difference in cataract type distribution.

Age Distribution↗
PubMed2001

Alcohol consumption and overall accident mortality in 14 European countries.

AIMS: To evaluate the effects of changes in aggregate alcohol consumption on overall accident mortality in 14 western European countries after 1950, and to compare traditional beer, wine, and spirits countries with respect to the impact of alcohol. DESIGN, SETTING AND PARTICIPANTS: The countries were sorted into three groups--traditional spirits countries of northern Europe, traditional beer countries of central Europe and wine countries of southern Europe. Gender- and age-specific annual mortality rates were analysed in relation to per capita alcohol consumption, utilizing the Box-Jenkins technique for time series analysis. All series were different to remove long-term trends. The results of the analyses in individual countries were pooled within each group of countries to increase the statistical power. MEASUREMENTS: Overall accident mortality data for 5-year age groups were converted to gender and age specific mortality rates in the age groups 15-29, 30-49 and 50-69 years. Rates were age adjusted within groups. Data on per capita alcohol consumption were converted to consumption per inhabitant 15 years and older. FINDINGS: The analyses demonstrated a statistically significant and positive relationship between changes in aggregate alcohol consumption in all three groups of countries. The estimated effect parameter was larger in northern Europe than in central Europe, and smallest in southern Europe. CONCLUSION: The results are compatible with the hypothesis that accident mortality rates are influenced by per capita alcohol consumption in southern, central and northern Europe. However, alcohol appears to play a larger role in northern Europe than in southern Europe.

Accidents↗