Dear Editor

Regarding the eLetter by McCartt and Geary.[1]

Our study had the specific, stated objective of determining whether New York’s ban on drivers’ use of hand-held phones led to short-term and long-term changes in the use rates of hand-held phones while driving. Our intent was not to assess the relative safety effects of hands-free versus handheld devices. In the discussion, we note that any substitution of hands-free phones for handheld phones may have diluted any potential crash effects of the law, but that we were not able to assess the extent to which such substitution took place.

There is a growing body of experimental research on the effects of drivers’ phone use on driver performance. As we state in the introduction to our study, there are experimental studies that suggest that performance degradations are similar for conversations with hand-held or hands-free devices. There also are studies that show impairments associated with the manual aspects of using phones that are not fully hands-free. It is unknown whether the findings of experimental studies apply to real-world driving, and the association between phone use and crash risk is not addressed with these methods. Thus, we do not agree with you that “there is a large body of evidence showing that there is no safety benefit to be gained from hands free devices.” Rather we believe it is an unsettled issue. We also are not aware of evidence from real-world studies of drivers to support the assertion that bans on drivers’ use of hand-held phones produce more frequent and longer calls on hands-free devices with more negative consequences. This also remains an unsettled issue.

Reference

1. Hockey. Handheld vs Handsfree [electronic response to A T McCartt and LL Geary; Longer term effects of New York State’s law on drivers’ handheld cell phone use] injuryprevention.com 2004http://ip.bmjjournals.com/cgi/eletters/10/1/11#42

Sir,

This article brings into prospective a dangerous and habitual practice of leaving infants and children unattended in vehicles and its serious ill effects on health most notably being death. Although the article describes scenario in a developed western setup such incidents are increasingly becoming common in developing Asian countries like India and require immediate attention.

The study addresses an important and often ignored issue of occurrence of hyperthermia in children left unattended in vehicles. There is a strong need that print and social media should bring such shocking occurrences into public domain more piercingly so that people specially parents together with caretakers would become aware of such problems leading to them being more careful and attentive. The community as a whole should bring about basic necessary changes in attitude and perception of individuals to prevent such dreadful events.

We agree with the authors that policy makers and law makers need to take a serious and stringent look into such issues so that timely interventions and strict regulations can be put into place. The community and government should work interactively towards developing guidelines, safety norms and mostly create awareness amongst ignorant parents.

Lastly we would like to state that in a country like India with warm winters and ambient temperatures being high normal in most part of country throughout the year along with little awareness about such a catastrophic phenomenon, a study in Indian context is urgently required.

Conflict of Interest:

None declared

Dear Editor

The study by Denton and Fabricius [1] uses local newspaper accounts to discover instances of defensive gun use in the Phoenix, Arizona area during a brief period in 1998 and concludes that there are far fewer such occurrences than reported by criminologists who performed nationwide telephone surveys. While telephone surveys are certainly vulnerable to some significant sources of bias, including those related to recall and self-reporting, it is hard to imagine that anyone would consider the methods used by Denton and Fabricius to be sound.

We belive that this work is fundamentally flawed for at least two reasons. First, the findings of criminologists confirm the intuitively obvious fact that most instances of defensive gun use are never reported to the police. Those who successfully use their guns in self-defense often would just as soon not involve the police. If a shooting does not result in a wounding or death, the police might very well never learn of the occurrence. If an individual wounded in such an incident did not seek medical attention (which would be subject to mandatory reporting to authorities), the police (again) would likely never learn of the incident. Finally, criminologists' surveys cited by Denton and Fabricius indicate that in the majority of defensive gun uses the firearm is not actually discharged. Instead, mere brandishing of the weapon deters the intentions of a criminal.

Second, the authors apparently assume that newspaper accounts are a reliable means of counting incidents of defensive gun use reported to the police. As sociologist John Lott documents in his recent book (The Bias Against Guns), newspapers routinely run stories of the criminal use of guns but rarely report defensive gun uses, which are considered much less "newsworthy." This judgment of newsworthiness may simply be based on the notion that an incident in which nobody actually got shot is less interesting to readers, but it probably also reflects the well-documented anti-gun bias of news reporters and editors. Given that the data collection methods employed by Denton and Fabricius are clearly inadequate to discover the actual number of defensive gun uses in the area and during the time period they attempted to examine, it is certainly impossible to use their data as the basis for drawing any valid conclusions.

I must say that I am nothing short of astonished that a journal produced by the elite BMJ Publishing Group would have accepted this manuscript for publication.

Reference

1. J F Denton and W V Fabricius. Reality check: using newspapers, police reports, and court records to assess defensive gun use. Inj Prev 2004; 10: 96-98.

Dear Editor

The article by Macpherson et al[1] relies on surveys from 111 sites around East York (Toronto) and some questions remain about these surveys. Data from two reports provides confusing indications on the level of cycling. In 2001[2] figures were published for the hourly rate for several years and by comparison in 2003[3] counts for 8-years were provided based on 1 hour observation at each site. An hourly rate is calculated base on the 111 sites and 1 hour per site ,'A' divided by 111. The table below shows the data;

Table 1 * data from 2003, 568 wearing helmets from 1227 is 46%, not 45 % as quoted in ref 1.

Robinson [4] stated "The Canadian study had 111 pre-selected sites, each recorded for one hour, but weather conditions were not reported (though elsewhere 1999 was described as a particularly sunny summer; A K Macpherson, personal communication). Table 1 in the Macpherson et al paper[2] shows that, in some years, some sites were recorded more than once. Moreover, observations were not at the same time of day and day of the week each year (A K Macpherson, personal communication)"

A number of aspects arise,
1) Can extra count details be added to the table, for 1999 and 2001.
2) Why the counts for years 1993 to 1997 were quite different in the published reports.
3) Why the total hours of surveys calculated should vary from 112 hours to 425 hours.
4) Why the observation hours were not a multiply of 111, as per number of sites.
5) Which survey details would be more likely to reflect the true level of cycling activity, 2001 or 2003, if either.
6) Could there have been an 17% drop in cycling, 2003 data - average count pre law 1275, post law 1059.
7) Can other data be added to the table.
8) How reliable are the surveys for indicating the overall level of cycling activity for those aged to 19 years.
9) Helmet use of 46% before legislation is identical to that in 2001 at 46%, seems like no appreciable effect from legislation.

Extra information would help provide a clearer picture to be guided by and most appreciated.

References
1. Macpherson AK, Macarthur C, To TM, et al. Economic disparity in bicycle helmet use by children six years after the introduction of legislation. Inj Prev 2006;12:231-235
2. Macpherson AK, Parkin PC, To TM. Mandatory helmet legislation and children’s exposure to cycling. Inj Prev 2001;7:228–30.
3. Parkin PC, Khambalia A, Kmet L, et al. Influence of socio-economic status on the effectiveness of bicycle helmet legislation for children: a prospective observational study. Pediatrics 2003;112:e192
4. Robinson DL, Helmet laws and cycle use, RESEARCH LETTER, Inj Prev 2003;9:380-381