The statistical variability of blood alcohol concentration measurements in drink-driving cases

Like many other places in the world, Hong Kong has drink-driving legislation which prohibits a driver from having in his blood alcohol exceeding a prescribed limit while in control of a motor vehicle. The accuracy of measuring this alcohol concentration is obviously of prime concern as an erroneous result can avert the administration of justice. The common practice is to deduct all errors from the measured value and compare the deducted value with the prescribed limit, so that the benefit of all errors of the measurement is given to the driver. It is therefore important for any laboratory responsible for measuring blood alcohol concentrations to identify and quantify all errors associated with the measurement. The present study examined 900 blood alcohol determinations carried out by the Hong Kong Government Laboratory (HKGL) on cases of suspected drink driving. The determinations were performed by 5 different analysts with two different sets of instruments during 1995-1997. Statistical analysis indicated that the instruments had no bearing on the random error or variability and that even though analyst was a significant factor on variability, the deviation from the mean so caused was only 0.3% and of no practical significance. When the systematic error introduced by the tolerance limits of the certified alcohol standards (purchased from the Laboratory of Government Chemists, UK) was taken into account, the total uncertainty (random plus systematic errors) of an alcohol determination at 99.5% confidence level was found to be 4%. It is recommended that laboratories engaged in blood alcohol determination should adopt similar statistical treatment of their analytical results to find out the error and to ensure that the results are independent of analyst and instrument used.     

Sudden death due to asphyxia by esophageal polyp: two case reports and review of asphyxial deaths

Asphyxia, not an uncommon cause of sudden death, may result from numerous etiologies. Foreign-body aspiration and strangulation are 2 extrinsic causes. Airway obstruction may also be caused by laryngeal edema, asthma, infection, or anaphylaxis. Chronic causes of asphyxia include musculoskeletal diseases (eg, muscular dystrophy, amyotrophic lateral sclerosis), neurologic disorders (eg, myasthenia gravis, multiple sclerosis), respiratory disease (eg, emphysema, chronic bronchitis), or tumors. The manner of death in cases of asphyxiation may be natural, accidental, homicide, or suicide. For the death investigator, determining the cause and manner of death can often be quite challenging.We report here 2 cases of an esophageal fibrovascular polyp causing sudden asphyxial death, review of the literature, and discussion of other differential diagnoses in the case of asphyxial death.     

Public opinion and the politics of obesity in America

Health policy experts have recently sounded the warning about the severe health and economic consequences of America's growing rates of obesity. Despite this fact, obesity has only begun to enter America's political consciousness and we have little information about what average Americans think of obesity or whether they support obesity-related policies. Using unique survey data collected by the authors, this essay examines public attitudes toward obesity and obesity policy. We find that, contrary to the views of health experts, most Americans are not seriously concerned with obesity, express relatively low support for obesity-targeted policies, and still view obesity as resulting from individual failure rather than environmental or genetic sources. Given the absence of elite discourse on this problem, we also find that typical determinants of policy preferences, such as ideology or partisanship, are not good predictors of attitudes on obesity policy. Rather, with a low-valence issue such as obesity, the public utilizes other attitudinal frameworks such as their opinions on smoking policy and the environmental culpability for obesity. The implications of these findings for obesity policy and research on health-related public opinion are discussed.     

Correlation of methamphetamine results and concentrations between head, axillary, and pubic hair

This study was designed to compare the qualitative results and concentrations of methamphetamine (MA) and its metabolite amphetamine (AP) in head hair and hair collected from different parts of the body (axillae and pubis). Hair from subjects (N = 14) suspected MA users was simultaneously collected. Hair preparation involved washing step, fine cutting, overnight extraction, derivatization by the trifluoroacetic anhydride, and gas chromatography/mass spectrometry (GC/MS) using selective ion monitoring. In this study, we found a good correlation of the qualitative results for MA between head hair and hair on other parts of the body, but there were some differences in concentrations of MA and AP. Namely, the concentrations of MA and AP were higher in axillary and pubic hair than in head hair.