We read with interest the article by Maguire et al 1, reporting the results of a systematic review of torn frenum and other intraoral injuries in diagnosing abuse. We do accept that in the absence of case control studies, the most appropriate study design to answer a diagnostic clinical question, the authors had to settle for case series or case studies. However, when none of the included case series were specifically designed to look for a torn frenum, any firm conclusion based on such studies is weak. It was also surprising to note that some of the studies that were given a rank of one for abuse (highly suggestive of abuse), were case reports based on a single child. Also, we thought it would be useful to point that the number of patients (in Table 4 and 5) do not add up and tally with the total number described in the text. Finally, we do agree that the best way forward is to conduct a well-designed comparative study involving our dental colleagues.

Competing interests: None declared

Reference

1 Maguire et al, Diagnosing abuse: a systematic review of torn frenum and other intra-oral injuries. Arch Dis Child.2007; 92: 1113-1117

In the February 2007 issue of the Archives, Mitchell(1) published a discussion document on recommendations for prevention of sudden infant death syndrome (SIDS), focussing particularly on the advice issued by the Department of Health (DoH) in England on 3 occasions, in 2000, 2004 and 2005. A revised version was published in February 2007,(2) too late for inclusion in Mitchell’s paper. In the paper he reviews some of the recent evidence pertaining to prevention of such deaths, and criticises the DoH for some of its current recommendations and, more generally, for relying largely on the Foundation for the Study of Infant Deaths (FSID) for the scientific advice on which their advice is based. This letter is a response to the paper on behalf of FSID. I shall take the specific points raised by Mitchell in the order in which they appear in his paper.

The definition of cot death

Mitchell states that “...the DoH uses the FSID definition of cot death” and “The FSID definition equates cot death with sudden unexpected death in infants (SUDI)”. The category SUDI includes some cases in which a complete or partial explanation for the death is found either from the autopsy findings or by detailed examination of the circumstances of the death: SIDS does not. This is true, but it is not clear that this has any important bearing on the advice that is given to prevent unexpected death in infancy generally, and Mitchell presents no evidence that it does.

Sleeping position

Both the DoH and FSID recommend supine sleeping (on the back) for all infants, with rare exceptions for medical reasons, in accordance with the international consensus which is based on much evidence from many countries. This includes a recommendation to avoid side, as well as front (prone) sleeping which has been shown to increase the risk of SIDS although much less so than for front sleeping. Mitchell hypothesises that the risk of side sleeping may be explained by the fact that infants placed on their side are more likely to roll into the prone position than those placed on their backs. However, this is unlikely to be the whole explanation since one recent study found that SIDS infants were more likely to be found dead on their sides, as well as having been placed in that position.(3) There is no obvious disparity between the advice currently issued by the DoH and that which Mitchell would favour.

Maternal smoking in pregnancy

Mitchell supports the advice that women should not smoke in pregnancy. He argues that “...the greatest benefit is achieved by getting light smokers to stop rather than heavy smokers to reduce the amount smoked”, based on figures published in the CESDI report into SUDI.(4) This conclusion depends on exactly how the odds ratios (ORs) are interpreted. If one converts the ORs into real figures, as advocated by Gigerenzer,(5) it is not quite so clear cut. Compared with a reference group of non- smoking mothers (group 1), the OR (95% confidence interval) of the risk of SUDI for babies born to mothers smoking 1-9 cigarettes daily (group 2) is 4.25 (2.93-6.18), that for babies born to mothers smoking 10-19 daily (group 3) is 6.49 (4.23-9.96) and that for babies born to mothers smoking 20+ daily (group 4) is 8.56 (5.12-14.31). If one makes the reasonable assumption that the incidence of SIDS in the reference group at the time of the study was 0.5 per 1,000 live births, for every 10,000 women in group 2 who stopped smoking the mean estimate of infant lives saved would be 16.25, while for every 10,000 women in group 4 who reduced their cigarette consumption to 10-19 per day the number of lives saved would be 10.35. However, for every 10,000 group 4 women who reduced their smoking to 1-9 cigarettes per day, the estimated number of lives saved would be 21.55. If a different estimate of the SIDS incidence in the reference group is substituted, the calculated numbers of lives saved would be somewhat different but the ratios between the effects of different degrees of smoking reduction would not. If the same exercise is performed using the ORs calculated in another published study,(6) not cited by Mitchell, the estimate of lives saved for every 10,000 women in group 2 who stopped smoking would be 8, as compared with 20.5 for every 10,000 group 4 women who reduced their consumption to that of those in group 3. It is obvious that, however the figures are manipulated, the greatest number of lives would be saved if all women abstained completely from smoking during pregnancy. Inserting small print into the advice to the effect that light smokers should stop and heavy ones should merely reduce their cigarette consumption seems likely to dilute the message and would very probably be counterproductive.

Bed sharing and room sharing

There is no dispute that bed sharing increases the risk of SIDS if the mother is a smoker, is under the influence of alcohol or other sedative drugs (prescription or not) or is ‘excessively tired’ (whatever that may mean for a woman caring for a baby aged less than 6 months). There is less agreement as to the risk if the mother does not come into any of the above risk categories, and especially if she is a non-smoker. As Mitchell points out, a meta-analysis by the European Concerted Action on SIDS Study(7) has shown a small but significant increase in risk for infants under about 12 weeks of age, and this is reinforced by the finding of 2 more recent studies.(8 9) Several reports have demonstrated that the risk of SIDS is approximately doubled if an infant sleeps in a separate room as compared with sleeping in a cot in the parents’ bedroom.(7 8 10 11) The FSID and DoH advice that “The safest place for your baby to sleep is in a cot in your room for the first six months of life” incorporates both these sets of findings as well as being unequivocal and easy to understand. The observation that “the advice is not explicit as to which components are most important” reflects the fact that we do not actually know which components are most important, but does not invalidate the advice.

Illness and infection

Mitchell argues that, because a recent German study (of which he is a co-author)(12) “has shown that infection is not a risk factor for SIDS in a population where few infants sleep prone” (the reference is wrongly cited in Mitchell’s article: his reference number 50 is an earlier study from New Zealand). Firstly, failure to demonstrate an effect does not mean that no effect exists (‘the curse of the null hypothesis’). Secondly, another recent study found that parents in families who had lost a previous child to SIDS were more likely to report non-specific symptoms and signs of illness in subsequent infants who died than in those who did not.(13) While doubt exists, it seems prudent to continue the advice to bring ill babies to professional advice in view of the vulnerability of small infants to illness of all kinds.

Breast feeding

Breast feeding has now been included in the FSID recommendations for prevention of SIDS following the recent publication of a meta-analysis by the US Agency for Healthcare Research and Quality,(14) which showed an OR of 0.64 (95% CI 0.51-0.81) for ‘ever’ breast feeding compared with no breast feeding.

Pacifier (dummy) use

Since February 2007 the DoH and FSID have advised that pacifier use may provide significant protection against SIDS following the publication of the two meta-analyses cited by Mitchell.(15 16) There was much overlap between the material analysed in these two reports and the statistical results of the two were very similar. Resistance to the use of pacifiers has largely been based on the fear that early use might interfere with the establishment of breast feeding, but there is no convincing evidence to this effect despite the publication of three controlled trials(17-19) (although one of them(19) showed a small negative effect of early introduction of a pacifier, at a mean age of 7 days, but none when the introduction was delayed until a mean of 28 days). Accordingly, the new recommendation is that dummies should be offered for all sleep periods from 1 month to 6 months of age.

Publication of the evidence base

FSID has produced a document (Factfile 2) summarising the published scientific evidence on which their recommendations are based. This has just been updated (2007) and is available on the FSID website at www.fsid.org.uk.

George Haycock Foundation for the Study of Infant Deaths, 11-19 Artillery Row, London SW1P 1RT Correspondence to: Professor G B Haycock, Scientific advisor, Foundation for the Study of Infant Deaths, 11-19 Artillery Row, London SW1P 1RT research@fsid.org.uk

References

1 Mitchell EA. Recommendations for sudden infant death syndrome prevention: a discussion document. Arch Dis Child 2007;92(2):155- 9. 2 Department of Health. Reduce the risk of cot death: an easy guide, 2007. http://www.dh.gov.uk/en/PublicationsAndStatistics/Publications/PublicationsPolicyAndGuidance/DH_4123625. 3 Blair PS, Platt MW, Smith IJ, et al. Sudden infant death syndrome and sleeping position in pre-term and low birth weight infants: an opportunity for targeted intervention. Arch Dis Child 2006;91(2):101-6. 4 Fleming PJ, Bacon C, Blair PS, et al., editors. Sudden unexpected deaths in infancy. The CESDI SUDI studies 1993-1996. London: The Stationery Office, 2000. 5 Gigerenzer G. Reckoning with risk: learning to live with uncertainty London: Penguin Books Ltd., 2002. 6 Poets CF, Schlaud M, Kleemann WJ, et al. Sudden infant death and maternal cigarette smoking: results from the Lower Saxony Perinatal Working Group. Eur J Pediatr 1995;154(4):326-9. 7 Carpenter RG, Irgens LM, Blair PS, et al. Sudden unexplained infant death in 20 regions in Europe: case control study. Lancet 2004;363(9404):185-91. 8 Tappin D, Ecob R, Brooke H. Bedsharing, roomsharing, and sudden infant death syndrome in Scotland: a case-control study. J Pediatr 2005;147(1):32-7. 9 McGarvey C, McDonnell M, Hamilton K, et al. An 8 year study of risk factors for SIDS: bed-sharing versus non-bed-sharing. Arch Dis Child 2006;91(4):318-23. 10 Blair PS, Fleming PJ, Smith IJ, et al. Babies sleeping with parents: case-control study of factors influencing the risk of the sudden infant death syndrome. CESDI SUDI research group. BMJ 1999;319(7223):1457- 61. 11 Mitchell EA, Thompson JMD. Co-sleeping increases the risk of SIDS, but sleeping in the parents' bedroom lowers it. In: Rognum TO, editor. Sudden infant death syndrome: new trends in the nineties. Oslo: Scandinavian University Press, 1995:266-9. 12 Vennemann MM, Findeisen M, Butterfass-Bahloul T, et al. Infection, health problems, and health care utilisation, and the risk of sudden infant death syndrome. Arch Dis Child 2005;90(5):520-2. 13 Wailoo M, Thompson JR, Waite AJ, et al. Signs and symptoms of illness in early infancy: associations with sudden infant death. Arch Dis Child 2003;88(11):1001-4. 14 Ip S, Chung M, Raman G, et al. Breastfeeding and maternal and infant health outcomes in developed countries. Evidence report/technology assessment No. 153 (prepared by Tufts-New England Medical Center Evidence- based Practice Center, under contract No. 290-02-0022): Agency for Healthcare Research and Quality, 2007:1-186. http://www.ahrq.gov/clinic/tp/brfouttp.htm. 15 Hauck FR, Omojokun OO, Siadaty MS. Do pacifiers reduce the risk of sudden infant death syndrome? A meta-analysis. Pediatrics 2005;116(5):e716-23. 16 Mitchell EA, Blair PS, L'Hoir MP. Should pacifiers be recommended to prevent sudden infant death syndrome? Pediatrics 2006;117(5):1755-8. 17 Schubiger G, Schwarz U, Tonz O. UNICEF/WHO baby-friendly hospital initiative: does the use of bottles and pacifiers in the neonatal nursery prevent successful breastfeeding? Neonatal Study Group. Eur J Pediatr 1997;156(11):874-7. 18 Kramer MS, Barr RG, Dagenais S, et al. Pacifier use, early weaning, and cry/fuss behavior: a randomized controlled trial. Jama 2001;286(3):322-6. 19 Howard CR, Howard FM, Lanphear B, et al. Randomized clinical trial of pacifier use and bottle-feeding or cupfeeding and their effect on breastfeeding. Pediatrics 2003;111(3):511-8.

Mahajan's study was commendable as it was pertinent to a large percentage of training paediatricians within the UK. Being of Indian ethnic origin myself (but from the African continent) I could relate to several issues highlighted by the article.

Barriers such as communication skills and work culture should also be viewed as goals or strengths whilst training within the NHS. These are major "barriers" when training within developing countries. The ever increasing patient load and lack of resources in these settings challenge medical personnel in achieving effective communication with the parent/patient. The focus on communication skills in the Royal College examinations are wholly appropriate. These desirable skills attained whilst training in the UK have afforded us (as future paediatricians) not only good medical practice, but also a boost of self-confidence and improved intercolleague relationships.

Team working has also influenced our improved communication skills. The focus on the "leader" within teams has fallen away and today all members are viewed with equal importance, each with their individual goals contributing towards a central goal. This UK work culture has humbled the "doctor" within us . It has heightened our appreciation and respect of other disciplines and personnel.

Job applications and visas do cause anxiety and are unfortunately a reality of being a foreigner working within the UK. This is time-consuming but absolutely necessary. It is a barrier for which we do not receive any support in the working environment.

Cultural differences do exist and integration within the society can be viewed as difficult to achieve. On a positive note, the UK is a multicultural society and foreigners are encountered on a day-to-day basis. Socialising is somewhat easier when people are aware of different cultures and are open minded. It is a matter of personal importance - the balance between learning new and retaining old cultural practices.

This study makes all aware of the barriers we face. I reinforce that some of these barriers have made us, as overseas doctors, better doctors and people in ourselves. It may in fact enhance our progress in the training process.

The argument by Roderick et al as to whether varicella vaccine should be introduced has particular relevance to Australia. Here, a single dose only is offered at 18 months, with a further opportunity in the teenage years for those without prior history of disease or vaccination. My concern lies in the provisional evidence of waning vaccine-induced immunity over time, as this will only result in chicken pox shifting from being a predominantly preschool illness to being an adult illness. Far from protecting those at higher risk of disease (like pregnant women and their unborn children), a childhood vaccine could create increased numbers of such an at-risk population. This potential long term implication of childhood vaccination needs to be addressed by answering the question whether two doses will provide lifelong immunity - or at least, from a paediatric point of view, through the child-bearing years.

It may be that with increased herd immunity these adults and pregnant women wil be at less risk, but overall I would still urge caution, and I would not be surprised if Australia sees an increase in congenital varicella or neonatal chicken pox in twenty to thirty years time, unless that 2nd dose is added in soon.