Juan de Dios Luna-del-Castillo

The influence of passengers on the risk of the driver causing a car collision in Spain. Analysis of collisions from 1990 to 1999.

OBJECTIVE To determine how the number of passengers, their age and their sex influence the risk of different types of Spanish drivers causing a collision between two or more cars. METHODS We selected, from the Spanish database of traffic crashes resulting in personal injuries or death, those collisions between two or more cars that occurred between 1990 and 1999 in which only one of the involved drivers committed a driving infraction. These drivers were considered the cases; non-infractor drivers were considered their matched controls. We collected information on the number, age and sex of the passengers in each vehicle, along with some potential confounding variables of the drivers and the vehicles involved. Crude and adjusted odds ratios were calculated for the main categories of driver and passenger. RESULTS A protective effect for the presence of passengers was detected (adjusted odds ratio: 0.69; 95% CI: 0.67-0.70). The protective effect was higher for drivers aged more than 45 years and lower for the youngest drivers (<24 years old). The strongest association was observed for female passengers who accompanied male drivers. The protective effect was lower for passengers older than 64 years. CONCLUSIONS Our results suggest that drivers are less likely to cause a car collision between two or more cars that results in personal injuries or death when they are accompanied by passengers, regardless of driver or passenger characteristics.

Proportion of Hospital Deaths Associated with Adverse Events

OBJECTIVES To determine the fraction of hospital deaths potentially associated with the occurrence of adverse events (AE). DESIGN A paired (1:1) case-control study. SETTING An 800-bed, teaching tertiary care hospital. PATIENTS All patients older than 14 years admitted to the hospital between January 1, 1990, and January 1, 1991, were eligible. All 524 consecutive deaths (death rate of 3.74%) that occurred in the hospital comprised the case group. For each case, a control patient was matched for both primary diagnosis on admission and admission date. MEASUREMENTS The proportion of hospital deaths associated with adverse events (defined as problems of any nature and seriousness faced by the patient during hospitalization, and potentially traceable to clinical or administrative management) was estimated from attributable risks adjusted for age, sex, service, severity of illness, length of stay, and quality of the medical record. RESULTS For stays longer than 48 hours, the adjusted attributable risk for all adverse events was estimated to be 0.51 (0.40-0.61). When the data were stratified according to the category of adverse event, the attributable risks remained significant except for administrative problems. The greatest proportion of deaths associated with adverse events was observed for surgical adverse events [0.56 (0.38-0.71)] and nosocomial infection [0.22 (0.14-0.28)]. CONCLUSIONS A significant proportion of intrahospital deaths were associated with AE. These results suggest the need to consider programs focused on the prevention of mortality from AE.

Proportion of hospital deaths potentially attributable to nosocomial infection.

OBJECTIVE To determine the fraction of hospital deaths potentially associated with nosocomial infection (NI). DESIGN A matched (1:1) case-control study. SETTING An 800-bed, tertiary-care, teaching hospital. PATIENTS All patients older than 14 years who were admitted to the hospital between January 1, 1990, and January 1, 1991, were eligible. All 524 consecutive deaths that occurred in the hospital comprised the case group. For each case, a control patient was matched for primary admission diagnosis and admission date. OUTCOME MEASURES The proportion of hospital deaths potentially associated with NI was estimated from the population attributable risk (PAR) adjusted for age, gender, service, severity of illness, length of stay, and quality of the medical record. RESULTS For stays longer than 48 hours, the PAR for all NIs was estimated to be 21.3% (95% confidence interval [CI95], 16.8%-30.5%). The greatest proportion of deaths potentially associated with NIs was observed in patients with only one infection (PAR, 15.0%; CI95, 10.9%-22.6%) and bacteremia or sepsis (PAR, 7.7%; CI95, 4.6%-11.6%). CONCLUSIONS NIs are associated with a large proportion of intrahospital deaths. This information may help clinicians and healthcare managers to assess the impact of programs for the prevention and control of NIs on intrahospital death.

Impact of different levels of carbohydrate intolerance on neonatal outcomes classically associated with gestational diabetes mellitus

OBJECTIVE To compare the influence of different levels of carbohydrate intolerance on neonatal outcomes. STUDY DESIGN The cohort constituted by the 1962 pregnant women screened for gestational diabetes who gave birth at the University Hospital of Granada (Spain) in the year 1995 was followed retrospectively. Women were classified into three groups: diagnosis of gestational diabetes, positive screen but non-gestational diabetes, and negative screen. Frequency of adverse newborn outcomes were quantified for each group and compared for statistical significance. RESULTS Gestational diabetes was associated with a greater incidence of high birth weight, hypoglycemia and hypocalcemia. Adequate metabolic control of the illness reduced the risk of adverse outcomes. Birth weight traced a positive slope with respect to the degree of carbohydrate intolerance. Regardless of carbohydrate intolerance, macrosomia was always higher among gravidae with gestational diabetes risk factors than among women without them. CONCLUSION Both maternal gestational diabetes risk factors and greater carbohydrate intolerance in gravidae are associated with an increase in adverse newborn outcomes.

Predictive value of a screen for gestational diabetes mellitus : influence of associated risk factors

Background. There is a need for solid evidence of the relative advantages of universal vs. selective screening for gestational diabetes mellitus. Our study of a broad obstetric population determines the positive predictive value of the 50‐g oral glucose challenge test for screening in the presence and absence of classical gestational diabetes risk factors.

Association of main driver-dependent risk factors with the risk of causing a vehicle collision in Spain, 1990–1999

PURPOSE To assess the strength of association of main driver-dependent risk factors with the risk of causing a collision between vehicles in Spain, from 1990 to 1999. METHODS The data for this paired-by-collision, case-control study were obtained from the Spanish Dirección General de Tráfico traffic crash database. The study included all 220284 collisions involving two or more vehicles with four or more wheels, in which only one of the drivers involved committed an infraction. Infractor drivers comprised the case group; noninfractor drivers involved in the same collision were their corresponding paired controls. RESULTS All driver-dependent factors were associated with the risk of causing a collision. The highest adjusted odds ratio estimates were obtained for sleepiness (64.35; CI, 45.12-91.79), inappropriate speed (28.33; CI, 26.37-30.44), and driving under the influence of alcohol with a positive breath test (22.32; CI, 19.64-25.37). An increase in the number of years in possession of a driving license showed a protective effect, albeit the strength of the effect decreased as age increased. CONCLUSIONS Our results emphasize the urgent need to implement strategies aimed mainly at controlling speeding, sleepiness, and alcohol consumption before driving-the main driver-dependent risk factors for causing a vehicle collision.

Effectiveness of Comparison Overlays Generated with DentalPrint© Software in Bite Mark Analysis*

ABSTRACT: Validation studies of the new DentalPrint© software were carried out with experimental bite marks in pigskin. The bite marks were digitally photographed according to the ABFO guidelines for evidence collection. Dental casts used in the experiment were scanned in 3D and 2D, and comparison overlays were generated using DentalPrint© and Adobe® Photoshop® software, respectively. Digitized photographs of the experimental bite marks and the biting edges obtained in the overlays were compared by two different examiners to analyze the impact of training and experience with the two methods. Receiver operating characteristic (ROC) analysis, sensitivity, specificity, and 95% confidence intervals for each cutoff point were calculated. The expert examiner using DentalPrint© obtained the best results, with an area under the ROC curve of 0.76 (SE=0.057; CI at 95%=0.652–0.876). Fairly high specificity values were found for DentalPrint©, and the best results were obtained for the cutoff value that discriminated between the examiners response “biter” and the rest of the possible (specificity 97.9%, CI at 95%=93.2%–99.6%). Therefore, the results presented here indicate that DentalPrint© is a useful, accurate tool for forensic purposes, although further research on the comparison process is needed to enhance the validity of bite mark analysis.

Comparison of two methods to assess the effect of age and sex on the risk of car crashes

BACKGROUND This study was designed to compare two methods (direct measurement of exposure and quasi-induced exposure) for assessing the effect of age and sex on the risk of being involved in a car crash in Spain. METHODS Spanish crash rates (per 10,000,000 driver-km) for age and sex groups of drivers aged 18-64 years old were obtained for 2004-2007, using information from the Spanish General Traffic Office (census of reported car crashes) and the Spanish Household Survey on Alcohol and Drugs (estimate of the mean km driven for each car driver). The rate ratios estimated by direct exposure estimates were compared to those obtained with the quasi-induced exposure method, which compares the age and sex of responsible and non-responsible drivers involved in the same clean collision (in which only one of the drivers committed a driving infraction). RESULTS Both methods detected an increased risk of involvement in a crash for the youngest (18-20 years) and the oldest drivers (60-64 years), compared to middle-aged drivers (45-49 years). However, the rate ratios obtained with the quasi-induced method for the youngest group (2.0 for men, 1.6 for women) were much lower than those obtained with crash rates (13.4 for men, 5.7 for women). Both methods detected a similar increase in the risk of involvement of male drivers compared to women in the youngest age group. This excess risk for men was maintained with increasing age up to 45-49 years when the quasi-induced method was used. However, direct comparisons of crash rates revealed an increased risk of involvement in women compared to men of the same age from 25-29 years onward. CONCLUSIONS Both direct measurement of driving exposure and the quasi-induced exposure method detected some well-known patterns of risk associated with drivers age and sex. However, factors that could explain important differences between the two methods deserve attention, especially those related with the excess risk for the youngest drivers as well as sex-related risk.

The association of age, sex and helmet use with the risk of death for occupants of two-wheeled motor vehicles involved in traffic crashes in Spain.

BACKGROUND This study was designed to separate the association of age, sex and helmet use with the risk of death for occupants of two-wheeled motor vehicles (TWMV) involved in crashes into its two theoretical components: severity of the crash and occupant resilience. METHODS We analyzed the retrospective cohort comprising all 48 016 pairs of drivers and passengers aged 14 years or more in TWMV involved in crashes with victims in Spain from 1993 to 2007 recorded in the Spanish traffic crash registry. The outcome (death or survival), age, sex and helmet use was known for both occupants. Adjusted relative risks (RR) for the association of age, sex and helmet with the risk of death were calculated with Poisson regression models. RESULTS Each 1-year increase in age was related with a 3% increase in the risk of death related with lower resilience. The severity-dependent RR of death was 1.84 for male sex and 0.86 for non-helmet use, and the resilience-dependent RR was 0.72 and 2.53, respectively. CONCLUSIONS The direction and magnitude of the association between age, sex and helmet use and the risk of death of an occupant of a TWMV involved in a crash changed depending on which component of risk was considered: crash severity or occupant resilience. Specifically, female sex and non-helmet use seemed to be associated with crashes of lower severity, but together with increased age they were also related with lower resilience to the energy released in the crash, and therefore with a higher risk of death after adjustment for crash severity. This should be taken into account when assessing the association of individual factors with the risk of death after a crash.

Contribution of exposure, risk of crash and fatality to explain age- and sex-related differences in traffic-related cyclist mortality rates.

This study was designed to quantify the percent contribution of exposure, risk of collision and fatality rate to the association of age and sex with the mortality rates among cyclists in Spain, and to track the changes in these contributions with time. Data were analyzed for 50,042 cyclists involved in road crashes in Spain from 1993 to 2011, and also for a subset of 13,119 non-infractor cyclists involved in collisions with a vehicle whose driver committed an infraction (used as a proxy sample of all cyclists on the road). We used decomposition and quasi-induced exposure methods to obtain the percent contributions of these three components to the mortality rate ratios for each age and sex group compared to males aged 25-34 years. Death rates increased with age, and the main component of this increase was fatality (around 70%). Among younger cyclists, however, the main component of increased death rates was risk of a collision. Males had higher death rates than females in every age group: this rate increased from 6.4 in the 5-14 year old group to 18.8 in the 65-79 year old group. Exposure, the main component of this increase, ranged between 70% and 90% in all age categories, although the fatality component also contributed to this increase. The contributions of exposure, risk of crash and fatality to cyclist death rates were strongly associated with age and sex. Young male cyclists were a high-risk group because all three components tended to increase their mortality rate.