Shanthi Ameratunga

Driver sleepiness and risk of serious injury to car occupants: population based case control study

Abstract Objectives: To estimate the contribution of driver sleepiness to the causes of car crash injuries. Design: Population based case control study. Setting: Auckland region of New Zealand, April 1998 to July 1999. Participants: 571 car drivers involved in crashes where at least one occupant was admitted to hospital or killed (“injury crash”); 588 car drivers recruited while driving on public roads (controls), representative of all time spent driving in the study region during the study period. Main outcome measures: Relative risk for injury crash associated with driver characteristics related to sleep, and the population attributable risk for driver sleepiness. Results: There was a strong association between measures of acute sleepiness and the risk of an injury crash. After adjustment for major confounders significantly increased risk was associated with drivers who identified themselves as sleepy (Stanford sleepiness score 4-7 v 1-3; odds ratio 8.2, 95% confidence interval 3.4 to 19.7); with drivers who reported five hours or less of sleep in the previous 24 hours compared with more than five hours (2.7, 1.4 to 5.4); and with driving between 2 am and 5 am compared with other times of day (5.6, 1.4 to 22.7). No increase in risk was associated with measures of chronic sleepiness. The population attributable risk for driving with one or more of the acute sleepiness risk factors was 19% (15% to 25%). Conclusions: Acute sleepiness in car drivers significantly increases the risk of a crash in which a car occupant is injured or killed. Reductions in road traffic injuries may be achieved if fewer people drive when they are sleepy or have been deprived of sleep or drive between 2 am and 5 am. What is already known on this topic Driver sleepiness is considered a potentially important risk factor for car crashes and related injuries but the association has not been reliably quantified Published estimates of the proportion of car crashes attributable to driver sleepiness vary from about 3% to 30% What this study adds Driving while feeling sleepy, driving after five hours or less of sleep, and driving between 2 am and 5 am were associated with a substantial increase in the risk of a car crash resulting in serious injury or death Reduction in the prevalence of these three behaviours may reduce the incidence of injury crashes by up to 19%

Road-traffic injuries: confronting disparities to address a global-health problem

Evidence suggests that the present and projected global burden of road-traffic injuries is disproportionately borne by countries that can least afford to meet the health service, economic, and societal challenges posed. Although the evidence base on which these estimates are made remains somewhat precarious in view of the limited data systems in most low-income and middle-income countries (as per the classification on the World Bank website), these projections highlight the essential need to address road-traffic injuries as a public-health priority. Most well-evaluated effective interventions do not directly focus on efforts to protect vulnerable road users, such as motorcyclists and pedestrians. Yet, these groups comprise the majority of road-traffic victims in low-income and middle-income countries, and consequently, the majority of the road-traffic victims globally. Appropriately responding to these disparities in available evidence and prevention efforts is necessary if we are to comprehensively address this global-health dilemma.

Incidence of traumatic brain injury in New Zealand: a population-based study

BACKGROUND Traumatic brain injury (TBI) is the leading cause of long-term disability in children and young adults worldwide. However, accurate information about its incidence does not exist. We aimed to estimate the burden of TBI in rural and urban populations in New Zealand across all ages and TBI severities. METHODS We did a population-based incidence study in an urban (Hamilton) and rural (Waikato District) population in New Zealand. We registered all cases of TBI (admitted to hospital or not, fatal or non-fatal) that occurred in the population between March 1, 2010, and Feb 28, 2011, using multiple overlapping sources of information. We calculated incidence per 100,000 person-years with 95% CIs using a Poisson distribution. We calculated rate ratios [RRs] to compare the age-standardised rates between sex, ethnicity, and residency (urban, rural) groups. We used direct standardisation to age-standardise the rates to the world population. RESULTS The total incidence of TBI per 100,000 person-years was 790 cases (95% CI 749-832); incidence per 100,000 person-years of mild TBI was 749 cases (709-790) and of moderate to severe TBI was 41 cases (31-51). Children (aged 0-14 years) and adolescents and young adults (aged 15-34 years) constituted almost 70% of all TBI cases. TBI affected boys and men more than women and girls (RR 1·77, 95% CI 1·58-1·97). Most TBI cases were due to falls (38% [516 of 1369]), mechanical forces (21% [288 of 1369]), transport accidents (20% [277 of 1369]), and assaults (17% [228 of 1369]). Compared with people of European origin, Maori people had a greater risk of mild TBI (RR 1·23, 95% CI 1·08-1·39). Incidence of moderate to severe TBI in the rural population (73 per 100,000 person-years [95% CI 50-107) was almost 2·5 times greater than in the urban population (31 per 100 000 person-years [23-42]). INTERPRETATION Our findings suggest that the incidence of TBI, especially mild TBI, in New Zealand is far greater than would be estimated from the findings of previous studies done in other high-income countries. Our age-specific and residency-specific data for TBI incidence overall and by mechanism of injury should be considered when planning prevention and TBI care services. FUNDING Health Research Council of New Zealand.

MEMO--a mobile phone depression prevention intervention for adolescents: development process and postprogram findings on acceptability from a randomized controlled trial.

Background Prevention of the onset of depression in adolescence may prevent social dysfunction, teenage pregnancy, substance abuse, suicide, and mental health conditions in adulthood. New technologies allow delivery of prevention programs scalable to large and disparate populations. Objective To develop and test the novel mobile phone delivery of a depression prevention intervention for adolescents. We describe the development of the intervention and the results of participants’ self-reported satisfaction with the intervention. Methods The intervention was developed from 15 key messages derived from cognitive behavioral therapy (CBT). The program was fully automated and delivered in 2 mobile phone messages/day for 9 weeks, with a mixture of text, video, and cartoon messages and a mobile website. Delivery modalities were guided by social cognitive theory and marketing principles. The intervention was compared with an attention control program of the same number and types of messages on different topics. A double-blind randomized controlled trial was undertaken in high schools in Auckland, New Zealand, from June 2009 to April 2011. Results A total of 1348 students (13–17 years of age) volunteered to participate at group sessions in schools, and 855 were eventually randomly assigned to groups. Of these, 835 (97.7%) self-completed follow-up questionnaires at postprogram interviews on satisfaction, perceived usefulness, and adherence to the intervention. Over three-quarters of participants viewed at least half of the messages and 90.7% (379/418) in the intervention group reported they would refer the program to a friend. Intervention group participants said the intervention helped them to be more positive (279/418, 66.7%) and to get rid of negative thoughts (210/418, 50.2%)—significantly higher than proportions in the control group. Conclusions Key messages from CBT can be delivered by mobile phone, and young people report that these are helpful. Change in clinician-rated depression symptom scores from baseline to 12 months, yet to be completed, will provide evidence on the effectiveness of the intervention. If proven effective, this form of delivery may be useful in many countries lacking widespread mental health services but with extensive mobile phone coverage. ClinicalTrial Australia New Zealand Clinical Trials Registry (ACTRN): 12609000405213; http://www.anzctr.org.au/trial_view.aspx?ID=83667 (Archived by WebCite at http://www.webcitation.org/64aueRqOb)

The contribution of alcohol to serious car crash injuries

Background: Alcohol impairment of drivers is considered the most important contributing cause of car crash injuries. The burden of injury attributable to drinking drivers has been estimated only indirectly. Methods: We conducted a population-based case–control study in Auckland, New Zealand between April 1998 and July 1999. Cases were 571 car drivers involved in crashes in which at least 1 occupant was admitted to the hospital or killed. Control subjects were 588 car drivers recruited on public roads, representative of driving in the region during the study period. Participants completed a structured interview and had blood or breath alcohol measurements. Results: Drinking alcohol before driving was strongly associated with injury crashes after controlling for known confounders. This was true for several measures of alcohol consumption: for self-report of 2 or more 12-g alcoholic drinks in the preceding 6 hours compared with none, the odds ratio (OR) was 7.9 (95% confidence interval = 3.4–18); for blood alcohol concentration 3 to 50 mg/100 mL compared with <3 mg/100 mL, the OR was 3.2 (1.1–10); and for blood alcohol concentration greater than 50 mg/100 mL compared with <3 mg/100 mL, the OR was 23 (9–56). Approximately 30% of car crash injuries in this population were attributable to alcohol, with two-thirds involving drivers with blood alcohol concentration in excess of 150 mg/100 mL. Equal proportions of alcohol-related injury crashes were attributable to drivers with blood alcohol concentrations of 3 to 50 mg/100 mL as those with levels of 51 to 150 mg/100 mL. Conclusion: Evidence about the proportion of crashes attributable to drivers at different blood alcohol concentrations can inform the prioritization of interventions that target different groups of drivers. These data indicate where there is the most potential for reduction of the injury burden.

Passenger carriage and car crash injury: a comparison between younger and older drivers

This study was conducted to investigate the effects of passenger carriage, including the number of passengers and the ages of passengers, on the risk of car crash injury. The study utilised data obtained from a case-control study conducted in the Auckland region of New Zealand between 1998 and 1999. Cases were car drivers who involved in crashes in which at least one occupant was hospitalised or killed. Controls were selected from a cluster random sample of car drivers on the roads in the same region. Self-report information on the numbers of passengers carried and their ages at the time of crash or at the time of the roadside survey, as well as potential confounding factors, was obtained from the drivers, or a proxy, using an interviewer-administered questionnaire. A total of 571 cases (93% response rate), including 195 younger drivers (aged <25 years), and 588 controls (79% response rate), including 94 younger drivers participated in the study. After adjusting for other risk factors, the odds of car crash injury among younger drivers was 15.55 times (95% CI 5.76-42.02) for those who carried two or more same age passengers, and 10.19 times (95% CI 2.84-36.65) for those who carried two or more other age passengers, compared with unaccompanied drivers. In comparison, no increase in risk was observed for older drivers who carried two or more passengers regardless of age. The carriage of two or more passengers, irrespective of the ages of passengers, significantly increases the risk of car crash injury among younger drivers. Passenger restriction as part of the graduate licensing system was discussed in the light of these results.

A systematic review of epidemiological studies investigating risk factors for work-related road traffic crashes and injuries

Objective: To critically appraise the published evidence for risk factors for injuries and deaths relating to work-related road traffic crashes. Design: Systematic review. Data sources: Electronic databases searched included Medline, EMBASE, PsycINFO, Transport database, and the Australian Transport and Road Index (ATRI) database. Additional searches included websites of relevant organizations, reference lists of included studies, and issues of major injury journals published within the past 5 years. Inclusion criteria: Studies were included if they investigated work-related traffic crashes or related injuries or deaths as the outcome, measured any potential risk factor for work-related road traffic crash as an exposure, included a relevant comparison group, and were written in English. Methods: Included studies were critically appraised using the GATE-lite critical appraisal form (www.epiq.co.nz). Meta-analysis was not attempted because of the heterogeneity of the included studies. Findings: Of 25 studies identified, three of four robust (case–control and case-crossover) studies found an increased injury risk (i) among workers after extended shifts, (ii) for tractor-trailers with brake and steering defects, and (iii) for “double configuration” trucks. The fourth study showed that alcohol and drug use were not risk factors in an industry with a random testing policy. The best cross-sectional studies showed associations between injury and sleepiness, time spent driving, occupational stress, non-insulin-dependent uncomplicated diabetes, and use of narcotics and antihistamines. Conclusions: Modifiable behavioral and vehicle-related risk factors are likely to contribute to work-related traffic injury. Fatigue and sleepiness—the most commonly researched topics—were consistently associated with increased risk.

The GATE frame: critical appraisal with pictures

Epidemiological evidence about the accuracy of diagnostic tests, the power of prognostic markers, and the efficacy and safety of interventions is the cornerstone of evidence-based health care.1 Practitioners of evidence-based health care require critical appraisal skills to judge the validity of this evidence. The Evidence-Based Medicine (EBM) Working Group members are international leaders in teaching critical appraisal skills, and their users’ guides for appraising the validity of the healthcare literature2 have long been the basis of teaching programmes worldwide. However, we found that many of our students took a reductionist “paint by numbers” approach when using the Working Group’s guides. Students could answer individual appraisal questions correctly but would have difficulty assessing overall study quality. We believe this is due to a poor understanding of epidemiological study design. So over the past 15 years of teaching critical appraisal we have modified the EBM Working Group approach and developed the Graphic Appraisal Tool for Epidemiological studies (GATE) frame to help our students conceptualise the whole study as well as its component parts. GATE is a visual framework that illustrates the generic design of all epidemiological studies (figure 1). We now teach critical appraisal by “hanging” studies and the EBM Working Group’s appraisal questions on the GATE frame. Figure 1  The GATE frame. This editorial outlines the GATE approach to critical appraisal, illustrated throughout using the Heart and Estrogen/progestin Replacement Study (HERS), a randomised, double blind, placebo controlled trial of the effect of daily oestrogen plus progestin on coronary heart disease (CHD) death in postmenopausal women.3 A detailed critical appraisal of HERS using a GATE-based checklist is available online.4 The GATE frame incorporates a triangle, circle, square, and arrow (figure 1), labelled with the acronym PECOT (or PICOT). The triangle (figure 2) represents the population studied: “P” for population or …

Invasive pneumococcal disease in a pediatric population, Auckland, New Zealand

Streptococcus pneumoniae is one of the major invasive pathogens in childhood. The increasing worldwide prevalence of penicillin-resistant strains makes management of invasive infections difficult and underscores the need for effective vaccines. Currently avaialable vaccines are of limited value in the pediatric age group. Trials are taking place to evaluate conjugated pneumococcal vaccines and in view of this it is important to establish local epidemiology of pneumococcal disease. The aims of this population-based study were to review all of the cases of invasive pneumococcal disease occurring during a 9-year period (1984 to 1992) in Auckland, New Zealand. Through the use of laboratory records and hospital discharge codes, 413 isolates from 407 patients were found. Age-specific incidence for all invasive disease was 22.0/100 000 for children less than 15 years old but 56.0/100 000 for children less than 5 years old (X2 Yates corrected 18.20; P = 0.001). Two-thirds were less than 2 years old. The rates were higher in Maori and Pacific Island children than in Caucasian children. A total of 70 isolates from 68 patients with meningitis occurred. The majority were less than 5 years old (incidence of meningitis was 10.0/100 000) and 84% were less than 2 years old. The overall mortality from meningitis was 4.3%. Of the 129 isolates serogrouped or serotyped, 14, 6 and 19 accounted for 23%, 16% and 16%, respectively, of cases. Although 98% of serotypes identified would be covered by the currently available 23-valent vaccine, two-thirds of the children affected by these isolates would be unprotected because of poor immunogenicity of polysaccharide vaccines in children less than 2 years old.

Conspicuity and bicycle crashes: preliminary findings of the Taupo Bicycle Study.

Objective: To describe the methods, characteristics of participants, and report on the preliminary findings of a longitudinal study of cyclists. Design: Web-based survey to establish a cohort of cyclists. Setting: Participants in the largest mass-participation bicycle event in New Zealand, the Wattyl Lake Taupo Cycle Challenge. Participants: 2469 riders who had enrolled online in the 2006 Wattyl Lake Taupo Cycle Challenge. Main outcome measures: Self-reported crashes in preceding 12 months. Results: Of 5653 eligible riders, 2469 (44%) completed the study questionnaire. Mean age was 44 years, 73% were male, and the average number of kilometers cycled per week in the preceding 12 months was 130. The annual incidence of crashes leading to injury that disrupted usual daily activities for at least 24 h was 0.5 per cyclist/year. About one-third of these crashes resulted in presentation to a health professional. The mean number of days absent from work attributable to bicycle crashes was 0.39 per cyclist/year. After adjustment for potential confounders and exposure (kilometers cycled per year), the rate of days off work from bicycle crash injury was substantially lower among riders who reported always wearing fluorescent colors (multivariate incidence rate ratio 0.23, 95% CI 0.09 to 0.59). Conclusions: Low cyclist conspicuity may increase the risk of crash-related injury and subsequent time off work. Increased use of high-visibility clothing is a simple intervention that may have a large impact on the safety of cycling.