Three year injury crash records of new licensees with suspensions or invalidity periods lasting 90 days or more.

A subset of new licensees, namely the ones with suspensions or invalidity periods of at least 90 days are studied. This subpopulation is comprised of 3,550 men and 1,295 women for whom the study file contains age, gender, licensing exam performance, and the dates all police reported crashes for the first three years after licensing. This group is compared with the complementary subpopulation of 53,069 men and 58,464 women. The average injury crash rate per year, not prorated, is 0.057 for men and 0.033 for women, about twice the rate for those without lengthy suspensions. These licensees are older, have lower success rates at licensing exams, and have a longer learning period than the others. Separate logistic-normal regression models for men and for women are estimated for the probability of a collision in a year using the available explanatory variables.

Impact of diabetes on crash risks of truck-permit holders and commercial drivers.

OBJECTIVE: The U.S. and some Canadian government agencies have waived commercial license restrictions for some insulin-using diabetic drivers. However, the U.S. Federal Highway Administration is no longer giving waivers. Scientific evidence to support such regulations has been sparse. This article presents detailed analyses of crash risks for users and nonusers of insulin among diabetic truck-permit holders in Québec, Canada. RESEARCH DESIGN AND METHODS: Diabetic truck-permit holders were group-matched by age to a random sample of healthy permit holders. Data on permits, medical conditions, and crashes involving 13,453 permit holder-years in 1987-1990 were extracted from the files of the public insurer for automobile injuries in Québec. Additional health status data were obtained from the provincial public health insurer. A telephone survey was conducted to collect data on driving patterns and exposure. Risk ratios were estimated using negative binomial regression models. RESULTS: Risk ratios for crashes vary by category of diabetes. Permit holders for single-unit trucks (STs) who are diabetic without complications and not using insulin have an increased crash risk of 1.68 when compared with healthy permit holders of the same permit class. When controlling for risk exposure, commercial drivers with an ST permit and the same diabetic condition have an increased risk of 1.76. Insulin use is not associated with higher crash risk. CONCLUSIONS: The increased crash risk for the group with uncomplicated diabetes not using insulin is a new finding. The lack of consistent increases in crash risks among diabetic commercial drivers with complications or who use insulin may be a "healthy worker effect" masking the real risk, because these licensees have a lower participation rate as professional drivers.

Individual differences in trajectory of intellectual development over 45 years of adulthood.

The hypothesis that individual differences in adult intellectual development reflect variation in life context and personality was examined in 132 World War II (WWII) veterans. Intelligence data from the Canadian Army M Test were available for 3 occasions, WWII, 1984-1986 (Int85), and 1989-1991 (Int90). Performance declined over the 45 years on 5 subtests but improved on the 6th, Vocabulary. Correlations between WWII and Int90 scores showed considerable stability of individual differences in intelligence over 45 years. Younger age predicted less decline over 45 years on all subtests; a more engaged lifestyle predicted less decline on most subtests, and better health and greater introversion predicted less decline on some subtests. Predictors of change since Int85 were similar to those for the whole period. Implications for theories of adult intellectual development are discussed.

Taxi drivers' accidents: how binocular vision problems are related to their rate and severity in terms of the number of victims.

Recent studies do not agree on the possible relationship between medical conditions and traffic safety; most of them do not control for exposure factors. In this study, we estimate the effect of binocular vision problems on taxi drivers' distributions of crashes (frequency). Moreover, given a crash, we estimate the effect of binocular vision problems on the distributions of the number of victims per crash (dead or injured). Our data and models permit the simultaneous consideration of many variables: age, medical condition, exposure factors measured by distance driven and time behind the wheel, qualitative risk factors, other characteristics of the driver, and crash circumstances in the models for the number of victims. Results show that taxi drivers have a large average number of crashes per year, larger for those with binocular vision problems compared with healthy ones, but not more severe in terms of the number of victims. The driver's past record (number of crashes and demerit points in the previous year) is a significant predictor of the number of crashes. Age is associated significantly with the number and the severity of crashes with older drivers having a better record than the youngest group (30 years old or less).

Everyday activity parameters and competence in older adults.

Parameters of everyday activities in relation to cognitive, social, and emotional competence were examined in 2 studies. The parameters included frequency, difficulty, importance, intentions for future activities, changes in past activities, and ability of performance. The challenge hypothesis, in which performance of optional activities experienced as moderately difficult is associated with greatest well-being, was also tested. Two samples of older adults completed a life history interview and measures of psychological functioning. Parameters of activities necessary for maintaining an independent engaged lifestyle were measured by the Everyday Activities Questionnaire. In both studies, competence variables helped explain activity parameters independently of age and demographic variables. There was no support for the challenge hypothesis in either study.

Medical conditions and the severity of commercial motor vehicle drivers' road accidents.

In this research we studied the association between commercial motor vehicle drivers' medical conditions and crash severity. Some aspects of medical condition were considered. To our knowledge, no study has ever isolated this association. The severity of a crash was measured by the total number of victims (injured and dead). We estimated nonlinear regression models (specifically, Poisson and negative binomial) which incorporated, simultaneously, information on drivers' characteristics, crash circumstances and health status, in order to isolate the association between health status and crash severity. Our results show that crashes of truck drivers with binocular vision problems and bus drivers with hypertension are more severe than those of healthy drivers. No other medical condition considered in this study was significantly associated with crash severity. Many variables describing crash circumstances were also significant.

Medical conditions, risk exposure, and truck drivers' accidents: an analysis with count data regression models.

Recent studies do not agree on the possible relationship between medical conditions and traffic safety; most of them do not control for exposure factors. This problem has become more pertinent for scientific studies because of litigation that showed that present regulations about access to driver permits might contravene human rights legislation. In our study, we estimate the effect of different medical conditions on truck drivers' distributions of accidents. Our data and our models permit simultaneous control for age; medical conditions; exposure factors measured by hours, kilometer, and qualitative factors; and other characteristics of truck drivers. Our results show that diabetic truck drivers of the permit class for straight trucks have more accidents than drivers in good health. No other studied medical condition has a significant effect on individual accident distributions. Many risk exposure variables are also significant. The effect of age is discussed in detail.

Neck injuries among belted and unbelted occupants of the front seat of cars.

This article, part of a recently completed research project on safety belts, presents results on neck injuries. A total of 3927 injured front-seat occupants (drivers and passengers) involved in two-car crashes were studied. Among them, 725 sustained neck sprains (ICD-9 code 847.0); some of them may have sustained other injuries as well. The more serious injuries to the cervical spine were more prevalent among the unbelted occupants. Neck sprains were relatively more numerous among belted occupants compared with unbelted ones, with a relative risk estimate of 1.68. Similar results hold also for subsets of the data on different types of collisions; the relative risks ranged from 1.39 to 2.42. A log linear model was constructed for the odds ratio (neck sprain vs. no neck sprain) taking into account the following factors: (1) seatbelt use, (2) direction of impact, (3) authorized speed limit, and (4) vehicle weight. The resulting relative risk estimate (belted vs. unbelted) became 1.58. The results raise questions about seatbelts and their protection against neck sprains.

Exposure for different license categories through a phone survey: validity and feasibility studies.

This paper presents: (i) an operational definition of risk exposure, (ii) a questionnaire developed to measure exposure, (iii) validity studies of estimates of the distance traveled and time spent driving for different permit holder categories, and (iv) a feasibility study for a telephone survey on exposure. Results show that long-distance truck drivers from one company studied estimated accurately their distance driven on the last worked day; Montreal Urban Community Transport Commission bus drivers estimated well their time behind the wheel; while a convenience sample of private car drivers (coworkers and friends) estimated well their previous week distance and time on the road. Phone surveys appear to be an efficient and cost-effective method for risk exposure data collection.

The effects of age and experience on accidents with injuries: should the licensing age be raised?

In Canadian Provinces and in several states of the United States the minimal legal age to drive a motor vehicle is 16 years old and in some, it is 15. The excess mortality and morbidity registered by 15 to 24-year-old drivers is well known. Several studies have reported that accident rates decrease with experience, but the effect of the age of new drivers has not been well documented. The objective is to study injury accident rates in terms of the age and experience factors. The data sources are computer files of the Government Insurance Corporation (Société de l'assurance automobile du Québec), which covers all Quebec drivers. For each driver, the file contains birth date, sex, year and month of first license, involvement in accidents, and other parameters. The yearly rates (1970-1984) of new permits per age last birthday and sex show an increase over time, particularly for 16-year-old men. For the period 1979-1984, injury accident involvement rates were computed for all Quebec drivers by age, sex, and driving experience. An experienced driver has been defined as a person who has been licensed for at least one year. The results show, for experienced as well as inexperienced young men (16-18), a high injury accident rate that decreases with age. For women, the rates are much lower and decrease more gradually than for men. This study does not take into account the kilometers driven. Since young drivers (16-18) have the highest accident rates, the question of regulating access to first licensing for such drivers must be examined as a possible strategy for injury prevention.

Association between hypothermia and mortality rate of premature infants--revisited.

The incidence of hypothermia (axillary temperature less than 35 degrees C) on admission of an infant to a neonatal intensive care unit was retrospectively analyzed in 559 very-low-birth-weight (less than 1500 gm) newborn infants. The smaller infants were at greater risk of hypothermia. Only in the larger neonates was mortality related to hypothermia, which suggests that this known association bears little cause-effect relationship.

Reliability of the twenty-four-hour nitrogen balance in parenterally fed newborn infants.

The reliability of shorter nitrogen balance determinations was evaluated in order to facilitate the nutritional assessment of parenterally fed infants. The intraindividual day-to-day variations of nitrogen intake, excretion, and retention were analyzed in 23 parenterally fed newborn infants (birth weight: 785-2630 g). Nitrogen retentions measured over 3 consecutive days were highly correlated (r = 0.90-0.96), and the reliability for a single 24-hr collection was estimated by r1 = 0.93. Nitrogen balance data obtained over a 24-hr period are reliable for the purpose of clinical investigations, provided the nutrient intake is constant.

The Wechsler subtests in mild organic brain damage associated with folate deficiency.

Forty-nine patients with low serum and cerebrospinal fluid folate levels completed the Ottawa-Wechsler Scale after 7-11 months of folate supplementation (10 mg daily). Twelve patients exhibited major neurological symptoms, while 37 patients displayed depression and minor neurological signs. After folate therapy, Verbal, Performance and Full Wechsler scores were significantly improved (P less than 0.001). The order of improvement in scores on the Wechsler subtests (from the statistically most significant to the least as measured by the t-statistics) was: Block Design, Digit Symbol, Similarities, Picture Completion, Picture Arrangement, Arithmetic, Object Assembly, Digit Span, Information, and Comprehension.

Phosphate uptake by superficial and deep nephron brush border membranes. Effect of the dietary phosphate and parathyroid hormone.

Dietary phosphate restriction and acute parathyroidectomy in rat are known to be associated with a selective increase in phosphate uptake by renal cortical brush border membranes (BBM). Conversely, phosphate loading and parathyroid hormone (PTH) administration result in a decrease of this uptake. In the present study, we investigated whether the response of the membrane to these various stimuli implies similar or different modifications of the kinetic properties of this membrane, whether these modifications affect one or both of the two systems of phosphate transport previously described, whether both superficial and deep nephron populations are involved, and whether the two stimuli: dietary phosphate, and parathyroid activity, are additive or not. Kinetic studies of phosphate (PO4) uptake by BBM vesicles were performed in seven groups of rats: control (N), acutely thyroparathyroidectomized (TPTX), PTH loaded (PTH), phosphate loaded (P+), phosphate depleted (P-), phosphate depleted with acute thyroparathyroidectomy (P-TPTX), and phosphate depleted-PTH loaded (P-PTH). In each of these experimental conditions, superficial and deep nephrons were investigated. Results indicated that 1. BBM from deep nephrons present a greater capacity for PO4 transport than those from superficial nephrons; 2. Whereas a dual system of PO4 uptake is observed in superficial BBM, deep BBM present only one single system; 3. Phosphate in the diet influences PO4 uptake by BBM to a greater extent in the deep than in the superficial nephrons; 4. PTH status on the contrary, equally influences both populations; 5. TPTX does not significantly enhance PO4 uptake in phosphate depleted rats; however, PTH loading curtails this uptake; 6.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebrospinal fluid and blood thiamine concentrations in phenytoin-treated epileptics.

Thiamine and folate levels in blood and cerebrospinal fluid (CSF) were determined by microbiological assays in 23 control subjects and 11 phenytoin-treated epileptics. There was no significant difference between the two groups for serum and CSF folate levels. There was, however, a statistically significant difference between the groups for both whole blood thiamine and CSF thiamine levels. Epileptic patients being treated with phenytoin had lower values than control subjects.

A simple combinatorial method for calculating genetic risks.

A method is presented whereby genetic counsellors can calculate genetic risks in a wide variety of circumstances using only arithmetics. The method is general in that it can handle such information as gene frequency, mutation rate, mode of inheritance, penetrance, pedigree to which the consultand belongs, phenotype of the consultand and his relatives, biochemical findings, etc. Each of the possible combinations of genotypes which may be present in the pedigree is listed and considered in turn. The method consists of a series of simple steps leading mechanically to the right answer.