Kemp et al.[1] attempted to retrospectively study the characteristics
and modes of bruising in children less than six years of age who had been
referred to two child protection teams. These children were placed in
physical abuse (PA) and physical abuse excluded (PAE) categories. An
important criterion used by Kemp et al. to select a child for the PA
category was the absence of a history of an accide...
Kemp et al.[1] attempted to retrospectively study the characteristics
and modes of bruising in children less than six years of age who had been
referred to two child protection teams. These children were placed in
physical abuse (PA) and physical abuse excluded (PAE) categories. An
important criterion used by Kemp et al. to select a child for the PA
category was the absence of a history of an accidental traumatic event;
however, the absence of a history of trauma is not diagnostic of physical
abuse. The lack of a history cannot universally be assumed to be due to
the caretakers' withholding of information regarding an abusive event[2].
Minor bruising and petechiae in children (including infants) are
commonly seen by office-based primary care physicians. Many do not have an
apparent explanation. The majority are not medically significant and are
appropriately not reported as concerning for abuse. Investigators should
not automatically include these cases in a PA category.
Importantly, Kemp et al.[1] did show that, despite an inherent
population bias and problematic selection criterion, 19.2% of pre-mobile
babies diagnosed as PAE had bruising. Even the Sugar et al.[3] study,
which has similar problems with selection bias, showed that 6 of a
thousand normal non-abused pre-mobile infants will have bruises. This
finding supports the concept that is known to experienced primary care
physicians: those who don't cruise can bruise without having been abused.
I support the authors' conclusion that when evaluating for child
abuse, not every bruise is necessarily abusive in etiology[4-5]. I agree
with the authors' assertion that their study population is skewed because
its population consists entirely of children who were initially suspected
to be victims of child abuse. When considered alongside the problematic
selection criterion noted above, this fact prompts me to question the
article's statistical conclusions.
REFERENCES
1 Kemp AM, Maguire SA, Nuttall D et al. Bruising in children who are
assessed for suspected physical abuse. Arch Dis Child. Published Online
First: 16 September 2013. doi: 10.1136/archdischild-2013-304339
2 Caffey J. Significance of the history in the diagnosis of traumatic
injury to children. Howland Award Address. J Pediatr 1965;67(5 Suppl):1008
-14S.
3 Sugar NF, Taylor JA, Feldman KW. Bruises in infants and toddlers:
those who don't cruise rarely bruise. Puget Sound Pediatric Research
Network. Arch Pediatr Adolesc Med 1999;153:399-403.
4 Laposata ME, Laposata M. Children with signs of abuse: when is it
not child abuse? Am J Clin Pathol 2005;123(Suppl 1):119-24.
5 Minford AM, Richards EM. Excluding medical and haematological
conditions as a cause of bruising in suspected non-accidental injury. Arch
Dis Child Educ Pract Ed 2010;95:2-8.
Conflict of Interest:
I do clinical research and medical legal evaluation regarding infant injury.
The School of Paediatrics in Yorkshire and Humber has already
embedded low resource exposure within its paediatric training programme.
Around 5 years ago we set up an annual scholarship for the tropical
medicine diploma. This is linked to 12 months out of programme time to
undertake a VSO placement via the RCPCH link. We have had 4 doctors
complete this linked programme, following a compet...
The School of Paediatrics in Yorkshire and Humber has already
embedded low resource exposure within its paediatric training programme.
Around 5 years ago we set up an annual scholarship for the tropical
medicine diploma. This is linked to 12 months out of programme time to
undertake a VSO placement via the RCPCH link. We have had 4 doctors
complete this linked programme, following a competitive entry process, so
far.
About 2 years ago I proposed a second scheme to the senior deanery
team to allow doctors from our programme "rotate" to the same resource
poor setting every 6 months to deliver health care, as well as training
and education. My proposal received unanimous support from the senior
deanery team. We utilised the experience of doctors from the rotation, who
had been on VSO attachment via the RCPCH to investigate possibilities and
location.
These enthusiastic doctors identified an opportunistic synergy in the
RCPCH engaging with the Global Links programme at the same time. In
Yorkshire and Humber we now have a queue of doctors who will "rotate" to
the same location every six months to deliver the ETAT+ programme for the
next 2 years. The first left in August 2013.
We have utilised the school's contacts with clinicians across
Yorkshire and Humber to identify several locations which would allow
reciprocal visitation. This will be part of the ongoing engagement with
global health for those doctors returning from their 6 month rotation, as
they will be expected to organise the exchanges. The school will match the
returning doctors' training rotation to a location that we know would look
favourably on this.
I would urge my fellow heads of school, if they have not already, to
develop a permanent rotational slot on their programmes to a resource poor
setting. I am hopeful that as the rotation is only 6 months and the
training programme is competency based that this innovation will not even
require a change in the completion date for most of those who undertake
this experience.
Yours sincerely,
Dr Simon J Clark
Head of School for Paediatrics in Yorkshire and Humber
I have updated the wikipedia entry on Duct Tape Occlusion Therapy to
make it clear that Jerome Litt (MD) first published this notion of using
Duct Tape to treat warts. It is likely to be further edited by others but
I thought the record needed clarifying.
http://en.wikipedia.org/wiki/Duct_tape_occlusion_therapy_(DTOT)_for_treating_verrucas_and_warts
I have updated the wikipedia entry on Duct Tape Occlusion Therapy to
make it clear that Jerome Litt (MD) first published this notion of using
Duct Tape to treat warts. It is likely to be further edited by others but
I thought the record needed clarifying.
http://en.wikipedia.org/wiki/Duct_tape_occlusion_therapy_(DTOT)_for_treating_verrucas_and_warts
We read with interest the article by Patti et al(1) and agree with
their conclusion that a history of normal voiding does not exclude a
diagnosis of posterior urethral valve (PUV). This has also been
demonstrated in other case series and reports.(2,3) The article by Patti
et al demonstrates a beautiful example of bilateral vesico-ureteric reflux
(VUR) on micturating cystourogram. We however raise...
We read with interest the article by Patti et al(1) and agree with
their conclusion that a history of normal voiding does not exclude a
diagnosis of posterior urethral valve (PUV). This has also been
demonstrated in other case series and reports.(2,3) The article by Patti
et al demonstrates a beautiful example of bilateral vesico-ureteric reflux
(VUR) on micturating cystourogram. We however raise the question of
whether the filling defect highlighted actually represents PUV (also
referred to as a congenitally obstructing posterior urethral membrane).
The classic narrowing of PUV is more distal in the urinary tract with
dilatation proximal to the filling defect. It is difficult to explain the
cystoscopy findings though leaflets of the normal anatomical structure,
plicae colliculi, can be visualised on cystoscopy and their role in
bladder outlet obstruction is debated. Bladder abnormalities are found in
a significant number of patients with VUR(4) and perhaps in this case of
reflux the urethra wasn't to blame at all.
References
1)Patti G, Naviglio S, Pennesi M, et al. Normal voiding does not
exclude posterior urethral valves. Arch Dis Child 2013;98:634
2)Bomalaski MD, Anema JG, Coplen DE, Koo HP, Rozanski T, Bloom DA.
Delayed presentation of posterior urethral valves: a not so benign
condition. J Urol. 1999 Dec;162(6):2130-2
3)Kanaroglou N, Braga LH, Massaro P, Lau K, Demaria J. Lower
abdominal mass in a 16-year old adolescent: an unusual presentation of
posterior urethral valves. Can Urol Assoc J. 2011 Feb;5(1):E1-3. doi:
10.5489/cuaj.10045.
4)Carpenter MA, Hoberman A, Mattoo TK, Mathews R, Keren R, Chesney
RW, Moxey-Mims M, Greenfield SP; RIVUR Trial Investigators. The RIVUR
Trial: Profile and Baseline Clinical Associations of Children With
Vesicoureteral Reflux. Pediatrics. 2013 Jul;132(1):e34-45. doi:
10.1542/peds.2012-2301. Epub 2013 Jun 10.
I find the response to Assistant Professor Samlaska to be a bit
limited.
Firstly, in the study by Wenner, they point out at the end of the
paper that unbeknownst to them the clear duct tape they used had a
different glue on it than regular duct tape. In fact, it had an acrylic
based glue. Furthermore, the control group treatment used moleskin - this
also has an acrylic based glue. So, when Wenner et al found no...
I find the response to Assistant Professor Samlaska to be a bit
limited.
Firstly, in the study by Wenner, they point out at the end of the
paper that unbeknownst to them the clear duct tape they used had a
different glue on it than regular duct tape. In fact, it had an acrylic
based glue. Furthermore, the control group treatment used moleskin - this
also has an acrylic based glue. So, when Wenner et al found no difference
between the effectiveness of treatments in the 2 groups, each of which has
used a patch adhered with acrylic-based glue. In other words, both groups
had largely the same treatment. It seems hardly surprising that they found
no difference in efficacy of treatment versus non-treatment groups.
Further I note the meta analyses done by Gibbs et al in 2006 and Kwok
in 2012 also failed to acknowledge this limitation.
Your comment that the families would not know the difference between
acrylic based or rubber based adhesive may be true but that only speaks to
a potential placebo effect, which given the other significant flaw in the
study, seems moot.
I have updated the wikipedia entry on duct tape occlusion therapy.
feel free to contribute to it. I have not referred to your study since it
is not freely available without subscription.
Thank you for your interest in our paper(1) and for your concern for
the proper management of children suffering from acute brain injury.
As you know, a concussion is a complex pathophysiologic process
resulting from a rapid rotational acceleration of the brain caused by
trauma.(2-4) It is a form of traumatic brain injury. The Glasgow Coma
Scale, on the other hand, was develo...
Thank you for your interest in our paper(1) and for your concern for
the proper management of children suffering from acute brain injury.
As you know, a concussion is a complex pathophysiologic process
resulting from a rapid rotational acceleration of the brain caused by
trauma.(2-4) It is a form of traumatic brain injury. The Glasgow Coma
Scale, on the other hand, was developed as a means of communicating the
neurological status of patients that have sustained a head injury. Its
value reflects a head-injured patient's vocalization, motor movements, and
eye movements, either spontaneously or in response to various stimuli.(5-
6) It is frequently used in the acute setting to transfer information from
one group of caregivers to another. It is not, however, reflective of a
specific diagnosis. A patient with a Glasgow Coma Scale score of 14, for
example, may be suffering from a concussion, or may have a subdural
hematoma, or an epidural hematoma, or cerebral edema, or a cerebral
contusion, or some combination of these injuries. As our objectives were
to determine the number of hospital admissions due to concussion, and to
determine the imaging and medications used for assessing and managing
concussions, we could not achieve our stated objectives by assessing
patients identified solely by their Glasgow Coma Scale scores.
Furthermore, as the Pediatric Health Information System is an
administrative database, such clinical data was not available to us.
We agree with your recommendation to discourage "the almost
indiscriminate" use of computed tomography of the brain. We believe, as
you suggest and as suggested by the paper by Nigrovic et al that we
referenced, a period of observation in place of computed tomography may be
a safe alternative for some patients. In fact, we suspect that a shorter
time period than the 24-48 hours you recommend may suffice. Our data
suggests that such an observation period would likely decrease the cost of
an emergency department visit when compared to the cost of a visit with
computed tomography.
Once again, we thank you for your interest in our work and for
offering your thoughts in response.
Yours Sincerely,
William P. Meehan III Cary Thurm Brian M. Pate Jason G. Newland Matt
Hall Jeffrey D. Colvin
References 1.)Colvin JD, Thurm C, Pate BM, Newland JG, Hall M, Meehan
WP, 3rd. Diagnosis and acute management of patients with concussion at
children's hospitals. Arch Dis Child published 13 July 2013,
10.1136/archdischild- 2012-303588. 2.)McCrory P, Meeuwisse W, Aubry M, et
al. Consensus statement on concussion in sport--the 4th International
Conference on Concussion in Sport held in Zurich, November 2012. Clin J
Sport Med. Mar 2013;23(2):89- 117. 3.) Meehan WP, 3rd, Bachur RG. Sport-
related concussion. Pediatrics. Jan 2009;123(1):114-123. 4.) Ommaya AK,
Gennarelli TA. Cerebral concussion and traumatic unconsciousness.
Correlation of experimental and clinical observations of blunt head
injuries. Brain. Dec 1974;97(4):633-654. 5.) Teasdale G, Jennett B.
Assessment and prognosis of coma after head injury. Acta Neurochirurgica.
1976;34(1-4):45-55. 6.) Teasdale G, Jennett B. Assessment of coma and
impaired consciousness. A practical scale. Lancet. Jul 13 1974;2(7872):81-
84
We read with interest the paper by Drs Colvin and colleagues on the
diagnosis and acute management of children with concussion at children?s
hospitals in the United States (1). The authors reported an astonishing
59.9% of children with concussion receiving CT scans of the head (1).
We would like to make two comments with regard to this study:
First, the terminology surrounding trauma to the head remains confus...
We read with interest the paper by Drs Colvin and colleagues on the
diagnosis and acute management of children with concussion at children?s
hospitals in the United States (1). The authors reported an astonishing
59.9% of children with concussion receiving CT scans of the head (1).
We would like to make two comments with regard to this study:
First, the terminology surrounding trauma to the head remains confusing
for patients, doctors and lay people alike (29. As a matter fact, there
are a great number of different definitions of what constitutes
"concussion" in the medical arena (2). Thus, instead of using the term
"concussion" we would suggest using objective measures of cerebral
dysfunction like the Glasgow Coma Scale (GCS) and dividing traumatic brain
injury into three different categories of severity, i.e. mild traumatic
brain injury (GCS: 13-15), moderate traumatic brain injury (GCS: 9-12),
and severe traumatic brain injury (GCS: 3-8).
Second, we were strongly surprised that roughly 60% of children with
concussions were submitted to cerebral CT scans (1). Of note, in this
study only 0.22% of children (ie roughly 1 in 500 children) had a
secondary diagnosis for intracranial injury (1). Moreover; the authors do
not provide any data whether these injuries mandated neurosurgical
interventions or were managed conservatively (1). Although CT scans will
likely differentiate those children who will need in-hospital treatment
from those who will not, the widespread and almost indiscriminate use of
CT scans should strongly be discouraged given the potential long-term
consequences including excessive cancer rates in children (3, 4). This
notion is also corroborated by the fact that an increase of children
sustaining less severe symptoms will present to the emergency department
(1). Instead, we would recommend close in-hospital observation for a
period of 24-48 hours to detect neurological changes and abnormalities
that will guide further diagnostic work-up (5, 6). In doing so, we could
reduce the number of cerebral imaging studies (sonography, CT and MRI) to
5 in 150 children with mild traumatic brain injury (GCS: 13-15), thus
keeping radiation exposure to a minimum (5, 6). Although this will come at
higher costs as demonstrated by Drs Colvin and colleagues (1), the future
health of our children should be worth the effort.
References
1.) Jeffrey D Colvin, Cary Thurm, Brian M Pate, Jason G Newland, Matt
Hall, William P Meehan, III. Diagnosis and acute management of patients
with concussion at children's hospitals. Arch Dis Child published 13 July
2013, 10.1136/archdischild-2012-303588
2.) Anderson T, Heitger M, Macleod AD. Concussion and mild head injury.
Pract Neurol. 2006;6(6):342-357
3.) Osmond MH, Klassen TP, Wells GA, Correll R, Jarvis A, Joubert G,
Bailey B, Chauvin-Kimoff L, Pusic M, McConnell D, Nijssen-Jordan C, Silver
N, Taylor B, Stiell IG; Pediatric Emergency Research Canada (PERC) Head
Injury Study Group. CATCH: a clinical decision rule for the use of
computed tomography in children with minor head injury. CMAJ. 2010 Mar
9;182(4):341-8. doi: 10.1503/cmaj.091421. Epub 2010 Feb 8.
4.) Miglioretti DL, Johnson E, Williams A, Greenlee RT, Weinmann S,
Solberg LI, Feigelson HS, Roblin D, Flynn MJ, Vanneman N, Smith-Bindman R.
The Use of Computed Tomography in Pediatrics and the Associated Radiation
Exposure and Estimated Cancer Risk. JAMA Pediatr. 2013 Jun 10:1-8.
5.) Oster I, Shamdeen GM, Gottschling S, Gortner L, Meyer S.
Electroencephalogram in children with minor traumatic brain injury. J
Paediatr Child Health. 2010 Jul;46(7-8):373-7
6.) Oster I, Shamdeen GM, Ziegler K, Eymann R, Gortner L, Meyer S.
Diagnostic approach to children with minor traumatic brain injury. Wien
Med Wochenschr. 2012 Sep;162(17-18):394-9
The highly commendable and detailed characterisation of non-anaemic
iron deficiency(1) is timely and, perhaps, even overdue, given the fact
that animal studies show that, even in the absence of anaemia, iron
deficiency can ,in its own right, adversely affect both cerebral
function(2), and thyroid function(3). In the animal model of non-anaemic
iron deficiency it has been shown that iron uptake by a divalent metal ion
tr...
The highly commendable and detailed characterisation of non-anaemic
iron deficiency(1) is timely and, perhaps, even overdue, given the fact
that animal studies show that, even in the absence of anaemia, iron
deficiency can ,in its own right, adversely affect both cerebral
function(2), and thyroid function(3). In the animal model of non-anaemic
iron deficiency it has been shown that iron uptake by a divalent metal ion
transporter(DMT-1) is essential for normal hippocampal neuronal
development and normal spatial memory behaviour(2). Furthermore, in
developing rats, there is a heterogenous loss of iron from the brain
following dietary iron deficiency, and a heterogenous restoration of iron
with iron therapy. What is more, early iron deficiency(and its correction
by iron replacement) "altered brain iron...in many regions different from
those observed in a later period"(4). Although there are no comparable
human data, the corollary to the animal study(4)is that "there might be
critical periods of infant development that absolutely require adequate
iron nutriture for normal development"(5). It has also to be recognised
that, in the human context, a causal relationship has not yet been clearly
established between iron deficiency during development and deficits in
cognitive and behavioural function(6).
The relationship between iron deficiency and cognitive function is
mirrored, to some extent, by the relationship between iron deficiency and
thyroid function where, again, the most convincing data come from animal
studies(3)(7). In the animal studies context, it has been shown that iron
deficiency significantly(P < 0.05) reduces thyroid peroxidase activity,
with the consequence that iron deficiency anaemia emerges as a significant
and independent predictor of both reduced serum triiodothyronine(T3)(p<
0.001), and reduced serum thyroxine(T4)(p < 0.0005)(3). Also in the
animal model, perinatal iron deficiency reduces serum total T3 by 43%, and
serum total T4 by 67%, and whole brain T3 by 25%(7).
The coexistence of iron deficiency and subclinical hypothyroidism mirrors
the relationship between iron deficiency and thyroid function(8). When the
two disorders coexist, patients randomised to combined iron and thyroid
replacement therapy experience significantly(p < 0.0001) greater
increase in blood haemoglobin and serum iron levels than patients
randomised to the sole use of iron replacement therapy(8). The other side
of the coin is that the use if iron replacement therapy in goitrous
children(mean age 8.5 in one study; mean age 10 in another) with iron
deficiency significantly)P < 0.001)improves the efficacy of iodised
salt in reducing thyroid size(9)(10). A study which has relevance to much
younger children is the one which showed that maternal iron deficiency
predicted both higher thyroid stimulating hormone and lower total T4
concentrations during pregnancy in Switzerland, the latter an area of
borderline iodine deficiency(11). Maternal hypothyroidism is, in turn, a
recognised predictor of significantly(p=0.005) poorer suboptimal
intellectual performance in their offspring(12).
Comment
In order to put non-anaemic iron deficiency in its proper context in
relation to iron deficiency anaemia we have to consider the study which
enrolled a sample of 504 consecutive children aged 1-3 in New York. Thirty
five percent of those children had evidence of iron insufficiency; 7% with
non-anaemic iron deficiency, and 10% with iron deficiency anaemia(13).
Given the potential neurodevelopmental impact of non-anaemic iron
deficiency(including its interaction with thyroid function), non-anaemic
iron deficiency is an entity which deserves to be characterised as fully
as possible so as to facilitate its identification and diagnosis.
Accordingly, for the sake of completeness, I would suggest that the most
decisive way to validate its diagnosis is to demonstrate a reduction in
the magnitude of red cell distribution width, and also a reduction in the
severity of hypochromia and/or microcytosis following iron replacement
therapy. Furthermore, in patients with non-toxic goitre, the diagnostic
trial of iron replacement therapy could be usefully accompanied by
monitoring of thyroid size during co-administration of iodised salt.
References
(1) Hinchliffe RF., Bellamy GJ., Finn A et al
Utility of red cell distribution width in screening for iron deficiency
Arch Dis Child 2013;98:545-547
(2)Carlson ES., Tkac I., Magid R et al
Iron is essential for neuron development and memory function in mouse
hippocampus
The Journal of Nutrition 2009;139:672-679
(3) Hess S., Zimmermann MB., Arnold M., Langhans W., Hurrell RF
Iron deficiency anemia reduces thyroid peroxidase activity in rats
J Nutr 2002;132:1951-1955
(4)Pinero DJ., Li N-Q., Connor JR., Beard JL
Variations in dietary iron alter brain metabolism in developing rts
J Nutr 2000;130:254-263
(5)Beard J
Iron deficiency alters brain development and functioning
J Nutr 2003;133:1468S-1472S
(6) McCann JC., Ames BN
An overview of evidence for a causal relation between iron deficiency
during development and deficits in cognitive or behavioural function
Am J Clin Nutr 2007;85:931-945
(7 Bastian TW., Prohaska JR., Georieff MK., Anderson GW
Perinatal iron and copper deficiencies alter neonatal rat circulating and
brain thyroid hormone concentrations
Endocrinology 2010;151:4055-4065
(8)Cinemre H., Bilir C., Gokosmanoglu F., Bahcebasi T
Hematologic effects of levothyroxine in iron-deficient subclinical
hypothyroid patients: A randomised, double-blind, controlled study
J Clin Endocrinol Metab 2009;94:151-156
(9)Hess SY., Zimmermann MB., Adou P., Torresani T., Hurrell RF
Treatment of iron deficiency in goitrous children improves the efficacy of
iodized salt in Cor d'Iviore
Am J Clin Nutr 2002;75:743-8
(10) Zimmermann MB., Zeder C., Chaouki N.,et al
Addition of microencapsulated iron to iodized salt improves the efficacy
of iodine in goitrous, iron deficicnt children: a randomized double-blind,
controlled trial
European Journal of Clinical Endocrinology 2002;147:747-753
(11)Zimmermann MB., Burgi H., Hurrell RF
Iron deficiency predicts poor maternal thyroid status during pregnancy
J Clin Endocrinol Metab 2007;92:3436-3440
(12)Mitchell ML., Klein RZ
The sequelae of untreated maternal hypothyroidism
European Journal of Endocrinology 2004;151:U45-U48
(13 Eden AN., Mir M
Iron deficiency in 1-3 year old children. A pediatric failure?
Arch Pediatr Adelosc Med 1997;151:986-988
I suggest breast feeding increases infant DHEA which positively
affects growth and development. Please read "DHEA is the Reason Breast
Milk is Beneficial," at: http://anthropogeny.com/DHEA%20Breast%20Milk.htm
We thank Dr. Johnson for his interest in our paper [1] and for the
opportunity to discuss methods for modelling child growth. Many methods
for modelling repeated measures data are available, and the strengths and
limitations of each method will depend on many factors, including the
specific research question of interest and the structure of the data being
analysed.[2] In our analysis, we used linear spline multilevel mode...
We thank Dr. Johnson for his interest in our paper [1] and for the
opportunity to discuss methods for modelling child growth. Many methods
for modelling repeated measures data are available, and the strengths and
limitations of each method will depend on many factors, including the
specific research question of interest and the structure of the data being
analysed.[2] In our analysis, we used linear spline multilevel models.
Such models divide age into separate 'pieces' joined with knot points, and
model a different linear slope between each pair of knots. Individual-
level random effects allow individuals to differ in both starting size
(birth length or weight) and in their rate of growth in each period of
childhood. Clearly, such a piecewise linear model is an approximation of
the true complex underlying growth pattern. However, a key advantage of
using linear splines to model infant and child growth is that they are
easy to interpret. As well as being a useful way of creating interpretable
summaries of growth trajectories, the linear spline approach provided good
fit to our data, for all ethnic and sex groups, as seen in Supplementary
web table 2 of our original paper.
Selection of knot points for linear spline models is an important
issue. However, Dr. Johnson is incorrect when he states that we used the
same knot points that had been derived from the Avon Longitudinal Study of
Parents and Children (ALSPAC) data. As reported in the statistical
analysis section of our paper, [1] we considered a series of models with
knot points at different ages, and selected the best fitting models for
the Born in Bradford data. These knot points were slightly different to
those used in the ALSPAC study. However, it is interesting to note that
this methodology has now been employed in several cohorts in varied
geographical settings and with different ethnic and socioeconomic
composition and that in each case, similar knot points that best fit the
data in these different studies have been identified.[3-8] The fact that
best-fitting models using data from very different populations have such
similar knot points gives some biological credibility to the periods of
growth identified by these models.
In the Born in Bradford cohort we had insufficient data in the first
month of life to model neonatal weight loss. When these methods are
applied to datasets with a greater number of measurements in early life,
it is possible to model neonatal weight loss. For example in the
Generation XXI cohort, based in Porto, Portugal, a median of ten growth
measures are available for each child within the first few years of life,
with almost all children having multiple growth measurements recorded in
the first months of life. In this cohort, linear spline multilevel models
with knot points at 10 days, 3 months and 1 year fit the data well.[8]
Dr. Johnson suggests that individual knot points should have been
used in our study. In contrast to our analyses, such models allow the age
of change points within growth trajectories to vary between individuals.
Allowing for individual-specific knot points may result in better fit of
the statistical model to the data.[9] But this increased model fit comes
at the cost of complexity and interpretability. The timing of knot points
is likely to be related to the rate of change before and after that knot
point, and thus these quantities would need to be interpreted carefully.
The potential added benefits of using this approach to address our
question of ethnic differences in growth depend on two main factors: how
variable knot points are likely to be between individuals, and whether the
timing of individual-specific knot points is of interest in its own right.
We do not feel that either of these actually support the use of this
method to address the research question we were answering. Individual
variation in, for example, the timing of puberty onset or the timing of
cognitive decline in older age [10] is likely to be considerably greater
than individual variation in the timing of changes in growth velocity in
infancy and early childhood; therefore models incorporating individual-
specific knot points may be more useful in the former situations than in
the latter. Likewise, our research question concerned describing ethnic
differences in rates of growth and was not concerned with ethnic
differences in the timing of features of early growth. Such an approach
would be useful when the research question centres on the timing of change
and how this timing relates to earlier exposures or later outcomes, for
example, when assessing whether age at puberty is associated with later
cardiovascular health, one would need to estimate individual age at onset
of puberty rather than assuming that this was constant across the
population.
We once again thank Dr. Johnson for his interest in our paper. Whilst
we recognise that linear spline models represent a simplification of the
true underlying growth process, we feel that they are a suitable
compromise between model fit, which was good in our study, and
interpretability. Examination of growth using different models is
important for triangulation, and different methods will be relevant for
different research questions.
Reference List
1. Fairley L, Petherick ES, Howe LD, Tilling K, Cameron N, Lawlor DA,
et al. Describing differences in weight and length growth trajectories
between white and Pakistani infants in the UK: analysis of the Born in
Bradford birth cohort study using multilevel linear spline models. Arch
Dis Child 2013,98:274-279.
2. Hauspie R, Cameron N, Molinari L. Methods in Human Growth
Research: Cambridge University Press; 2004.
3. Howe LD, Tilling K, Galobardes B, Smith GD, Gunnell D, Lawlor DA.
Socioeconomic differences in childhood growth trajectories: at what age do
height inequalities emerge? J.Epidemiol.Community Health 2012,66:143-148.
4. Paternoster L, Howe LD, Tilling K, Weedon MN, Freathy RM, Frayling
TM, et al. Adult height variants affect birth length and growth rate in
children. Hum.Mol.Genet. 2011,20:4069-4075.
5. Matijasevich A, Howe LD, Tilling K, Santos IS, Barros AJ, Lawlor
DA. Maternal education inequalities in height growth rates in early
childhood: 2004 Pelotas birth cohort study. Paediatr.Perinat.Epidemiol.
2012,26:236-249.
6. Tilling K, Davies N, Windmeijer F, Kramer MS, Bogdanovich N,
Matush L, et al. Is infant weight associated with childhood blood
pressure? Analysis of the Promotion of Breastfeeding Intervention Trial
(PROBIT) cohort. Int.J.Epidemiol. 2011,40:1227-1237.
7. Tilling K, Davies NM, Nicoli E, Ben-Shlomo Y, Kramer MS, Patel R,
et al. Associations of growth trajectories in infancy and early childhood
with later childhood outcomes. Am.J.Clin.Nutr. 2011,94:1808S-1813S.
8. Howe LD. Individual trajectories of childhood growth in five
cohorts: the application of linear spline multi-level models. In:
EUCCONET/ Society for Longitudinal and Life Course Studies. Paris; 2012.
9. Bellera CA, Hanley JA, Joseph L, Albertsen PC. Hierarchical
changepoint models for biochemical markers illustrated by tracking
postradiotherapy prostate-specific antigen series in men with prostate
cancer. Ann Epidemiol 2008,18:270-282.
10. van den Hout A, Muniz-Terrera G, Matthews FE. Change point models
for cognitive tests using semi-parametric maximum likelihood. Comput Stat
Data Anal 2013,57:684-698.
Dear Editor:
Kemp et al.[1] attempted to retrospectively study the characteristics and modes of bruising in children less than six years of age who had been referred to two child protection teams. These children were placed in physical abuse (PA) and physical abuse excluded (PAE) categories. An important criterion used by Kemp et al. to select a child for the PA category was the absence of a history of an accide...
Dear Editor,
The School of Paediatrics in Yorkshire and Humber has already embedded low resource exposure within its paediatric training programme.
Around 5 years ago we set up an annual scholarship for the tropical medicine diploma. This is linked to 12 months out of programme time to undertake a VSO placement via the RCPCH link. We have had 4 doctors complete this linked programme, following a compet...
I have updated the wikipedia entry on Duct Tape Occlusion Therapy to make it clear that Jerome Litt (MD) first published this notion of using Duct Tape to treat warts. It is likely to be further edited by others but I thought the record needed clarifying. http://en.wikipedia.org/wiki/Duct_tape_occlusion_therapy_(DTOT)_for_treating_verrucas_and_warts
Conflict of Interest:
None...
Dear Editor,
We read with interest the article by Patti et al(1) and agree with their conclusion that a history of normal voiding does not exclude a diagnosis of posterior urethral valve (PUV). This has also been demonstrated in other case series and reports.(2,3) The article by Patti et al demonstrates a beautiful example of bilateral vesico-ureteric reflux (VUR) on micturating cystourogram. We however raise...
I find the response to Assistant Professor Samlaska to be a bit limited.
Firstly, in the study by Wenner, they point out at the end of the paper that unbeknownst to them the clear duct tape they used had a different glue on it than regular duct tape. In fact, it had an acrylic based glue. Furthermore, the control group treatment used moleskin - this also has an acrylic based glue. So, when Wenner et al found no...
Dear Drs. Meyer and Oster,
Thank you for your interest in our paper(1) and for your concern for the proper management of children suffering from acute brain injury.
As you know, a concussion is a complex pathophysiologic process resulting from a rapid rotational acceleration of the brain caused by trauma.(2-4) It is a form of traumatic brain injury. The Glasgow Coma Scale, on the other hand, was develo...
We read with interest the paper by Drs Colvin and colleagues on the diagnosis and acute management of children with concussion at children?s hospitals in the United States (1). The authors reported an astonishing 59.9% of children with concussion receiving CT scans of the head (1).
We would like to make two comments with regard to this study: First, the terminology surrounding trauma to the head remains confus...
The highly commendable and detailed characterisation of non-anaemic iron deficiency(1) is timely and, perhaps, even overdue, given the fact that animal studies show that, even in the absence of anaemia, iron deficiency can ,in its own right, adversely affect both cerebral function(2), and thyroid function(3). In the animal model of non-anaemic iron deficiency it has been shown that iron uptake by a divalent metal ion tr...
I suggest breast feeding increases infant DHEA which positively affects growth and development. Please read "DHEA is the Reason Breast Milk is Beneficial," at: http://anthropogeny.com/DHEA%20Breast%20Milk.htm
Conflict of Interest:
None declared
We thank Dr. Johnson for his interest in our paper [1] and for the opportunity to discuss methods for modelling child growth. Many methods for modelling repeated measures data are available, and the strengths and limitations of each method will depend on many factors, including the specific research question of interest and the structure of the data being analysed.[2] In our analysis, we used linear spline multilevel mode...
Pages