Graduated driver licensing in Michigan: early impact on motor vehicle crashes among 16-year-old drivers

CONTEXT: Graduated driver licensing (GDL) programs are being adopted in many states to address the high rate of motor vehicle fatalities among teens by requiring teenaged drivers to gain experience and maturity under conditions of relatively low crash risk before gaining full driving privileges. OBJECTIVE: To evaluate the early impact of Michigan's GDL program on traffic crashes among 16-year-old drivers. DESIGN, SETTING, AND SUBJECTS: Analysis of Michigan motor vehicle crash data from 1996 (before GDL program implementation) vs 1998 and 1999 (after GDL program implementation) for 16-year-olds, adjusting for trends among persons 25 years or older. INTERVENTION: Michigan's GDL program, instituted April 1, 1997, for teens younger than 18 years entering the driver license system, includes 3 licensure levels, each with driving restrictions and requirements to progress to the next level. Requirements include extended, supervised practice in the learning level, 2-phase driver education, and night driving restrictions in the intermediate level. MAIN OUTCOME MEASURES: Rates in 1996 vs 1998 and 1999 for all police-reported crashes; for fatal injury, nonfatal injury, and fatal/nonfatal injury combined crashes; for day, evening, and night crashes; for single-vehicle and multivehicle crashes; and for alcohol-related crashes. RESULTS: Overall, the rate of 16-year-old drivers (per 1000 population) involved in crashes declined from 154 in 1996 to 111 in 1999 (relative risk [RR], 0.72; 95% confidence interval [CI], 0.71-0.73). After adjusting for populationwide trends, the overall crash risk for 16-year-olds was significantly reduced in 1999 from 1996 by 25% (adjusted RR, 0.75; 95% CI, 0.74-0.77). There were also significant reductions for nonfatal injury and combined fatal and nonfatal crashes; for day, evening, and night crashes; and for single-vehicle and multivehicle crashes. Fatal crashes declined from 1996 to 1999, but not significantly (RR, 0.74; 95% CI, 0.49-1.14), and alcohol-related crashes continued at a low rate (RR, 1.01; 95% CI, 0.80-1.29). CONCLUSIONS: Analysis of the first 2 full calendar years following Michigan's GDL program implementation indicates substantial crash reductions among 16-year-olds. Future research is necessary to determine if these reductions are maintained and if other jurisdictions achieve similar results.     

Travel as a risk factor for venous thromboembolic disease

There is increasing evidence that prolonged travel may be associated with the development of venous thromboembolic disease: ie deep venous thrombosis and pulmonary embolism. The data from case reports, retrospective reviews and case control studies have been confirmed by prospective studies. There have been several prospective studies of subjects embarking on airline flights of greater than 4 hours duration aimed at determining the incidence of DVT as detected by ultrasonography. In unprotected subjects, the incidence of thrombosis in the calf veins or muscular veins ranged between 0% and 10%. There is evidence that the incidence of travel-related pulmonary embolism appears to be related to the distance travelled and immobility during the flights. Whether the imputed causation is merely due to immobility and venous compression or to other factors associated with the aircraft cabin requires further clarification. The use of below-knee graduated compression stockings appears to be highly effective. A 100 AXa U/kg single dose of a low molecular weight heparin, given 2-4 hours before the flight, have been reported to be more effective than aspirin and placebo. However, the benefit/risk ratio of such a strategy remains to be assessed.     

Plasma prekallikrein as a risk factor for diabetic retinopathy

BACKGROUND: The aim of the study was to verify the hypothesis that in diabetes there is an increased activation of coagulation system leading in consequence to diabetic retinopathy. METHODS: Thirty three healthy subjects (controls, 16 males and 17 females) and 35 patients with diabetes type 1 (15 males and 20 females) were examined. We monitored plasma prekallikrein (PPK), glycemia, fructosamine, glycosylated hemoglobin, activated partial thromboplastin time (PTT), INR, fibrinolysis in euglobulins time (FET), level of antithrombin III (AT III), fibrinogen (Fb) and fibrinogen degradation products (FDP). RESULTS: In diabetic patients without retinopathy, PKK concentration was 16% higher (p <0.005), in patients with background retinopathy 33% higher (p <0.001), and in patients with proliferative retinopathy PKK concentration was 50% higher (p <0.001) than in controls. In the subgroup of patients with proliferative retinopathy PTT was significantly shorter (p <0.001), and FET was significantly longer (p <0.001) than in control. In patients with diabetes higher FDP concentrations were found than in controls (p <0.05). Significant correlations were found between PPK and fructosamine levels in all diabetic patients (R(S)=+0.57 p <0.001), in diabetic patients without retinopathy (R(S)=+0.61, p <0.05), and in diabetic patients with retinopathy (R(S)=+0.62, p <0.005). We found negative correlation between PPK concentration and PTT (R(S)=-0.43, p <0.001) and positive correlation between PPK concentration and FET (R(S)=+0.59, p <0.00001) in the entire study group. CONCLUSIONS: The occurrence of diabetic retinopathy is connected with higher levels of plasma prekallikrein.     

Migraine as a risk factor for subclinical brain lesions

Context  Clinical series have suggested an increased prevalence of cerebral infarction and white matter lesions (WMLs) in migraine patients. It is not known whether these lesions are prevalent in the general migraine population. Objectives  To compare the prevalence of brain infarcts and WMLs in migraine cases and controls from the general population and to identify migraine characteristics associated with these lesions. Design  Cross-sectional, prevalence study of population-based sample of Dutch adults aged 30 to 60 years. Participants  Randomly selected patients with migraine with aura (n = 161), patients with migraine without aura (n = 134), and controls (n = 140), who were frequency matched to cases for age, sex, and place of residence. Nearly 50% of the cases had not been previously diagnosed by a physician. Main Outcome Measures  Brain magnetic resonance images were evaluated for infarcts, by location and vascular supply territory, and for periventricular WMLs (PVWMLs) and deep WMLs (DWMLs). The odds ratios (ORs) and 95% confidence intervals (CIs) of these brain lesions compared with controls were examined by migraine subtype (with or without aura) and monthly attack frequency (<1 attack, =" BORDER="0">1 attack), controlling for cardiovascular risk factors and use of vasoconstrictor migraine agents. All participants underwent a standard neurological examination. Results  No participants reported a history of stroke or transient ischemic attack or had relevant abnormalities at standard neurological examination. We found no significant difference between patients with migraine and controls in overall infarct prevalence (8.1% vs 5.0%). However, in the cerebellar region of the posterior circulation territory, patients with migraine had a higher prevalence of infarct than controls (5.4% vs 0.7%; P = .02; adjusted OR, 7.1; 95% CI, 0.9-55). The adjusted OR for posterior infarct varied by migraine subtype and attack frequency. The adjusted OR was 13.7 (95% CI, 1.7-112) for patients with migraine with aura compared with controls. In patients with migraine with a frequency of attacks of 1 or more per month, the adjusted OR was 9.3 (95% CI, 1.1-76). The highest risk was in patients with migraine with aura with 1 attack or more per month (OR, 15.8; 95% CI, 1.8-140). Among women, the risk for high DWML load (top 20th percentile of the distribution of DWML load vs lower 80th percentile) was increased in patients with migraine compared with controls (OR, 2.1; 95% CI, 1.0-4.1); this risk increased with attack frequency (highest in those with =" BORDER="0">1 attack per month: OR, 2.6; 95% CI, 1.2-5.7) but was similar in patients with migraine with or without aura. In men, controls and patients with migraine did not differ in the prevalence of DWMLs. There was no association between severity of PVWMLs and migraine, irrespective of sex or migraine frequency or subtype. Conclusions  These population-based findings suggest that some patients with migraine with and without aura are at increased risk for subclinical lesions in certain brain areas.      

Post menopausal bleeding as a risk factor for endometrial carcinoma

From July 1985 to January 1989, 133 patients underwent endometrial sampling for evaluation of post menopausal bleeding (PMB). Of these patients, 114 (85.7 percent) showed benign histology with an average age of 58.6 years. Nineteen (14.3 percent) were malignant, all of which showed endometrial carcinoma. The average age was 65. In addition, 26.3 percent of patients with carcinoma had higher grade of tumor at hysterectomy when compared with the preoperative biopsy. The average volume of tissue removed at curettage was significantly greater in those with carcinoma. Hormonal therapy, duration of symptoms, hypertension, obesity or diabetes were not significant risk factors for carcinoma in our series. PMB remains a major symptom that may predict endometrial carcinoma and must be evaluated. In those patients with carcinoma, intraoperative evaluation of the uterus for tumor grade and depth of invasion is important in determining the extent of surgery.     

Benign melanocytic naevi as a risk factor for malignant melanoma

Examination of 180 patients with cutaneous malignant melanoma and 197 control patients in a case-control study showed that the risk of melanoma is strongly related to numbers of benign melanocytic naevi (moles). Some unusual features of naevi--a diameter exceeding 7 mm, colour variation, and irregular lateral outline--also showed a strong association with the risk of melanoma, but the relation of numbers of naevi to risk was present even in the group of patients whose naevi had none of these unusual features. Biopsy of clinically atypical naevi from several of the patients at highest risk generally did not show dysplastic histology. Thus a group of people at high risk of melanoma may be identified by using simple clinical assessment of naevi.     

Use of alcohol as a risk factor for bicycling injury

CONTEXT: Bicycling is one of the leading causes of recreational injuries. Elevated blood alcohol concentrations (BACs) are found in about one third of fatally injured bicyclists aged 15 years or older. OBJECTIVE: To assess the relative risk of fatal and serious bicycling injury according to BAC. DESIGN: Matched case-control study. SETTING AND SUBJECTS: Bicyclists aged 15 years or older who were fatally or seriously injured while riding a bicycle during the day in Maryland in 1985-1997 (cases, n = 124) and bicyclists aged 15 years or older who were interviewed and given a breath test for estimated BAC during roadside surveys that took place in June 1996 through May 1998 at the same site, time of day, day of week, and month of year in which a case bicyclist was injured (controls, n = 342). MAIN OUTCOME MEASURE: Odds ratio of bicycling injury according to estimated BAC. RESULTS: An estimated positive BAC (>/=0.02 g/dL) was detected in 12.9% of the case bicyclists (23.5% of the 34 fatally injured and 8.9% of the 90 seriously injured) compared with 2.9% of the control bicyclists (P<.001). Relative to an estimated BAC of less than 0.02 g/dL, the adjusted odds ratio of bicycling injury was 5.6 (95% confidence interval [CI], 2.2-14.0) for a BAC of 0.02 g/dL or higher and was 20.2 (95% CI, 4.2-96.3) for a BAC of 0.08 g/dL or higher. Rates of helmet use at the time of injury or interview were 5% and 35%, respectively, for those with and without a positive BAC (P =.007). CONCLUSION: Alcohol use while bicycle riding is associated with a substantially increased risk of fatal or serious injury.     

Adverse reactions to allogeneic whole blood donation by 16- and 17-year-olds

Anne F. Eder, MD, PhD; Christopher D. Hillyer, MD; Beth A. Dy, BS; Edward P. Notari IV, MPH; Richard J. Benjamin, MD, PhD

JAMA. 2008;299(19):2279-2286.

Context  Donations by minors (16- and 17-year-olds) now account for approximately 8% of the whole blood collected by the American Red Cross, but young age and first-time donation status are known to be independent risk factors for donation-related complications.

Objective  To evaluate adverse reactions to allogeneic whole blood donation by 16- and 17-year-olds compared with older donors in American Red Cross blood centers.

Design, Setting, and Participants  Prospective documentation of adverse events among 16- and 17-year-old donors using standardized collection protocols, definitions, and reporting methods in 2006. Data were from 9 American Red Cross blood centers that routinely collect from 16- and 17-year-olds, a population that provides 80% of its donations at high school blood drives.

Main Outcome Measures  Rate of systemic (syncopal-type) and phlebotomy-related donor complications per 10 000 collections.

Results  In 2006, 9 American Red Cross regions collected 145 678 whole blood donations from 16- and 17-year-olds, 113 307 from 18- and 19-year-olds, and 1 517 460 from donors aged 20 years or older. Complications were recorded in 15 632 (10.7%), 9359 (8.3%), and 42 987 (2.8%) donations in each corresponding age group. In a multivariate logistic regression model, young age had the strongest association with complications (odds ratio [OR], 3.05; 95% confidence interval [CI], 2.52-3.69; P < .001), followed by first-time donation status (OR, 2.63; 95% CI, 2.24-3.09; P < .001) and female sex (OR, 1.87; 95% CI, 1.62-2.16; P < .001). Infrequent but medically relevant complications, in particular physical injury from syncope-related falls, were significantly more likely in 16- and 17-year-old donors (86 events; 5.9/10 000 collections) compared with 18- and 19-year-old donors (27 events; 2.4/10 000 collections; OR, 2.48; 95% CI, 1.61-3.82) or adults aged 20 years or older (62 events; 0.4/10 000 collections; OR, 14.46; 95% CI, 10.43 -20.04). Sixteen-year-old donors who experienced even a minor complication were less likely to return to donate within 12 months than 16-year-olds who experienced uncomplicated donations (52% vs 73% return rate; OR, 0.40; 95% CI, 0.36-0.44).

Conclusions  A higher incidence of donation-related complications and injury occurs among 16- and 17-year-old blood donors compared with older donors. The increasing dependence on recruiting and retaining young blood donors requires a committed approach to donor safety, especially at high school blood drives.

     

Lupus anticoagulant as a risk factor for cerebral infarction and habitual abortions

A case involving a 34-year-old female with a progressive hemiparesis is described. She had a history of repeated spontaneous abortions. The CT and magnetic resonance imaging (MRI) showed a multiple cerebral infarction. A 99mTc perfusion lung scintigram demonstrated diffuse bilateral perfusion defects in the lungs. The presence of lupus anticoagulant (LA) was detected from the laboratory data and the thrombosis in the genital organ. The repeated abortions were probably due to thrombosis in the placental vessels caused by LA. High dose steroid therapy was effective in suppressing the LA activity and in preventing progression of the clinical symptoms.     

Lp(a) lipoprotein as a risk factor for myocardial infarction

The Lp(a) lipoprotein is structurally related to low-density lipoprotein but is found in lower plasma concentration. It has been associated with coronary disease in several white populations. To test the generalizability of this association, we measured serum Lp(a) by quantitative immunoelectrophoresis in 303 Hawaiian men of Japanese ancestry with a prior myocardial infarction (MI) and in 408 population-based controls. Mean values were 17.1 and 13.7 mg/dL (0.171 and 0.137 g/L), respectively. Increased risk for MI was shown mainly for men in the upper quartile of the Lp(a) lipoprotein distribution (greater than or equal to 20.1 mg/dL [greater than or equal to 0.201 g/L]). Odds ratios at younger than 60, 60 to 69, and 70 years of age or older were 2.5, 1.6, and 1.2 times those for men in the lower three quartiles, respectively. In a multiple logistic model the association with MI remained significant and was not explained by differences in total cholesterol levels, high-density lipoprotein or low-density lipoprotein cholesterol levels, subscapular skin fold, systolic blood pressure, history of smoking, alcohol consumption, or age. We conclude that Lp(a) is an important attribute that should often be considered when coronary heart disease risk is assessed.