Reliability and minimal detectable change values for performance-based measures of physical functioning in the Canadian Longitudinal Study on Aging (CLSA)

BACKGROUND

The aim of this study was to determine the relative and absolute reliabilities of five key performance-based measures of physical function in the Canadian Longitudinal Study on Aging (CLSA).

METHODS

An age-stratified sub-sample of 147 participants from the CLSA who were undergoing their 3-year data collection visit participated in two repeat visits (within one week). Participants underwent tests of grip strength, 4-metre gait speed, Timed Up and Go (TUG), chair-rise and single-leg stance (left, right, mean, maximum). Intra-class correlation coefficients (ICC), standard error of measurement (SEM) and minimal detectable change (MDC) values were calculated.

RESULTS

The relative reliability for grip strength was excellent (ICC = 0.95); the TUG and single-leg stance tests had good reliability (ICC = 0.80 or 0.78-0.82, respectively); gait speed and the chair-rise test had moderate reliability (ICC=0.64 for both) for participants overall. For participants between 50 and 64 years, TUG and gait speed had poor reliabilities (ICC = 0.38 or 0.33, respectively). For participants aged 75+ years, the single-leg stance had poor reliability (ICC=0.30-0.39). The MDC90 was about 6 kg for grip strength, 2.3 seconds for TUG, 0.2 metres/second for gait speed, 5.2 seconds for chair-rise, and ranged from 22.8 to 26.2 seconds for the single-leg stance.

CONCLUSIONS

Among community-dwelling Canadians >50 years old, the reliabilities of the CLSA measures were moderate to excellent. The TUG and gait speed in the youngest age group, and the single-leg stance in oldest age group, showed poor reliability. MDC values can be used to interpret changes over time.

Bull bars and vulnerable road users

OBJECTIVES

Pedestrian injuries are a leading cause of the global death and injury burden, accounting for 65 percent of the 1.2 million annual road deaths. The purpose of this brief literature review is to examine whether bull bars, a rigid aftermarket accessory fitted to the front end of passenger vehicles, increase the risk of severe and fatal injuries to vulnerable road users in the event of a collision.

METHODS

Applicable peer-reviewed research, review papers, and grey literature were identified from a search of MEDLINE; the Transportation Research Board (TRB) database composed of Transportation Research Information Services (TRIS) and International Transport Research Documentation (TRID) databases; the Cochrane Database of Systematic Reviews; and Google Scholar. The following search terms were used: "bull bars" OR "nudge bars" OR "sahara bars" AND "pedestrians" OR "vulnerable road users" for 1948 to March 1, 2011. A secondary set of search terms was also included "bull bars" OR "nudge bars" OR "sahara bars" OR "vehicle frontal protective systems" AND "pedestrians" OR "vulnerable road users" for 1948 to March 1, 2011.

RESULTS

Neither the MEDLINE search nor the Cochrane Review search returned any relevant literature. The TRID search returned 19 research articles, 9 of which were included. Searches using Google Scholar returned 110 items, of which 21 were included in the present review after excluding patents and citations. Seven of the articles from TRID were also found in the Google Scholar search, resulting in 23 unique articles being included in this review. The studies used included 12 real-world studies, 3 computer modeling studies, and 8 laboratory testing studies. Very few studies examined the road safety of pedal-cyclists and motorcyclists; therefore, we focused solely on studies examining pedestrian safety.

CONCLUSIONS

The literature reviewed in this study indicates that vehicles fitted with bull bars, particularly those without deformable padding, concentrate crash forces over a smaller area of vulnerable road users during collisions compared to vehicles not fitted with a bull bar. Rigid bull bars, such as those made from steel or aluminum, stiffen the front end of vehicles and interfere with the vital shock absorption systems designed in vehicle fronts. These devices therefore significantly alter the collision dynamics of vehicles, resulting in an increased risk of pedestrian injury and mortality in crashes. This literature review shows that bull bars do indeed increase the severity of injuries to vulnerable road users in the event of a collision and highlights the need for current traffic safety policies to reflect the safety concerns surrounding the use of bull bars.

Youth injuries in British Columbia: type, settings, treatment and costs, 2003-2007

In this study, the types and costs of unintentional injuries among adolescents transitioning to adulthood are examined to provide age-appropriate prevention strategies. The data were collected in 2003, 2005 and 2007, in which a total of 273 (41%), 228 (39%) and 176 (33%) youths, respectively, reported to be having at least one serious injury. The leading types of injuries were sprains/strains, broken bones and bruises. Most injuries occurred while playing sports, falling/tripping, biking or rollerblading, mainly in recreation centres (>12-15%), schools (<27-9%), and workplaces (>2-14.5%). Most injuries were treated at emergency departments, walk-in clinics and health professional's offices (68-84%). Prevention included: doing nothing; being more careful; giving up the activity and rarely, rehabilitation or physiotherapy. The total direct cost of treatment was $471,498, (Canadian) at a mean direct cost of $775 per injury. Improved sports training and educational strategies targeted at subgroups of adolescents are needed to reduce the human and economic burden of injury.

Sociodemographic factors associated with aggressive driving behaviors of 3-wheeler taxi drivers in Sri Lanka

Little is known about the nature and scope of aggressive driving in developing countries. The objective of this study is to specifically examine the sociodemographic factors associated with aggressive driving behavior among 3-wheeler taxi drivers in Sri Lanka. Convenience samples of 3-wheeler taxi drivers from Rathnapura, Ahaliyagoda, Sri Lanka were surveyed from June to August 2006. Analyses included bivariate and multivariate logistic regression. Drivers with less than high school education were 3.5 times more likely to drive aggressively (odds ratio [OR] = 3.46; 95% confidence interval [CI] = 1.08, 11.1). Single drivers were 9 times more likely to run red lights (OR = 8.74; 95% CI = 2.18, 35.0), and being single was a major risk factor for drunk driving (OR = 4.80; 95% CI = 1.23, 18.7). Furthermore, high school completers were 4 times more likely to bribe a policeman (OR = 4.27; 95% CI = 1.23, 14.9) when caught violating the road rules. Aggressive driving and risk-taking behavior are amenable to policy initiatives, and preventive programs targeted at key groups could be used to improve road safety in Sri Lanka. This study demonstrates that aggressive driving behavior is associated with sociodemographic factors, including the level of education, marital status, and other socioeconomic factors. Hence, economic factors should be addressed to find solutions to traffic-related issues. It will be the government's and policy makers' responsibility to try and understand the economic factors behind risky road behavior and bribe-taking behavior prior to legislating or enforcing new laws.

Are 1994 alcohol production and the sales deregulation policy in Japan associated with increased road traffic fatalities among adult and teenage males and females in Japan?

INTRODUCTION

International studies have shown a significant association between alcohol availability and traffic crashes that involve alcohol-impaired drivers. A key limitation to previous alcohol availability and motor vehicle crash (MVC) evaluation research is the assumption of population homogeneity in responding to the policies. The present analysis focuses on the evaluation of the impact of alcohol availability on different segments of the Japanese population by comparing MVC fatality rates from before and after implementation of the alcohol deregulation policy in 1994.

SUBJECTS AND METHOD

Poisson regression with robust standard error was used to model the before-to-after change in incidence rate ratios (IRR) in adult males, adult females, teenage males and teenage females. To control potential confounders, unemployment rate, vehicle miles of travel (VMT), vehicle registration, and number of drivers licensed in Japan were added to the model. The exponents of the fitted coefficients are equivalent to incidence rate ratios.

RESULTS

Implementation of the policy deregulating alcohol sales and production did not appear to increase traffic fatalities among adult or teenage males or females in Japan. We found that male adult fatalities demonstrated a statistically significant decline following enactment of the deregulation policy in 1994.

DISCUSSION

Contrary to previous research, the findings of this study demonstrated lower rates of fatalities and higher compliance with alcohol-related driving legislation in Japanese society following implementation of the deregulation policy in 1994. Further well designed, nonaligned studies on alcohol availability and traffic fatalities in other countries are urgently needed.

Impact of lowering the legal blood alcohol concentration limit to 0.03 on male, female and teenage drivers involved alcohol-related crashes in Japan

In June of 2002, a revision to part of the Road Traffic Act drastically increased the penalties for drinking and driving offences in Japan. Most notably, the legal blood alcohol concentration (BAC) limit for driving was lowered from 0.05 mg/ml to 0.03 mg/ml. The rationale for the new lower BAC limit was predicated on the assumption that drinking drivers will comply with the new, lower limit by reducing the amount of alcohol they consume prior to driving, thereby lowering their risk of crash involvement. This, in turn, would lead to fewer alcohol-related crashes. A key limitation of previous lower BAC evaluation research in determining the effectiveness of lower legal BAC limit policies is the assumption of population homogeneity in responding to the laws. The present analysis is unique in this perspective and focuses on the evaluation of the impact of BAC limit reduction on different segments of the population. The chief objective of this research is to quantify the extent to which lowering the legal limit of BAC has reduced male, female and teenager involvement in motor vehicle crashes in Japan since 2002. Most notably, the introduction of reduced BAC limit legislation resulted in a statistically significant decrease in the number of alcohol-impaired drivers on the road in Japan, indicating responsiveness to the legal change among adults and teenagers. In addition, this preliminary assessment appears to indicate that the implementation of 0.03 BAC laws and other associated activities are associated with statistically significant reductions in alcohol-involved motor vehicle crashes. In comparison, the rates of total crashes showed no statistically significant decline nor increase in the period following the introduction of the BAC law, indicating that the lower BAC limit only had an effect on alcohol-related crashes in Japan. The evidence suggests that the lower BAC legal limit and perceived risk of detection are the two most important factors resulting in a sustained change in drinking and driving behaviour in Japan. It is recommended that future research and resources in other countries be focused on these factors as determinants to reduced alcohol-related crashes.