Childhood growth Flashcards

1
Q

Define growth:

A

change in body size over time (height, weight, BMI)

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2
Q

How would you plot and label a growth chart?

A

growth rate/velocity = slope of line
time = x-axis
size = y-axis

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3
Q

Why is growth the unique paediatric indicator of well-being?

A

it monitors child endocrine, nutritional, emotional and physical health

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4
Q

Who published the first growth curve, and when?

A

Le Comte de Montbeillard (for his son), in 1777

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5
Q

Why should we assess growth?

A
  • identify abnormal growth
  • specify a growth disorder
  • proxy for general ill health
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6
Q

What are the growth assessment principles?

A
  1. Purpose to distinguish abnormal from normal
  2. Needs high quality measurement (training, calibration, quality control)
  3. Correct recording (chart plotting and interpretation)
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7
Q

What is a centile?

A

percentage point of the frequency distribution

e.g. cut-off that identifies that percentage of children with measurements below it

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8
Q

What must be made sure of centiles and SD scores?

A
  • normally distributed

- each centile corresponds to number of SDs above/below the mean (SD score = z-score)

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9
Q

In a growth distance and velocity chart, what does “current size” indicate?

A

distance travelled

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10
Q

In a growth distance and velocity chart, what does “centiles crossing” indicate?

A

velocity of travel

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11
Q

When the growth chart quantifies size/distance, we say it is….

A

centile

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12
Q

When the growth chart does not quantify growth velocity, we say it is….

A

centile crossing uncalibrated

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13
Q

What is the nine centile format?

A

improved cut-offs for screening (2nd and 0.4th centile replace 3rd centile)

  • pick up rate of different screening strategies in this
  • clear recommendation for referral
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14
Q

Let’s say you’re looking at child growth, the 3rd centile would pick up how much % of children?

A

3% (1 in 33)

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15
Q

Let’s say you’re looking at child growth, the 2nd centile would pick up how much % of children?

A

2.3% (1 in 44)

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16
Q

Let’s say you’re looking at child growth, the 0.4th centile would pick up how much % of children?

A

0.4% (1 in 260)

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17
Q

What is the aim in, lets say, constructing growth charts?

A

to define weight distribution at each age

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18
Q

What 3 things could be noted from constructing growth charts?

A
  • skewness
  • nonlinear age trend
  • variability changes with age
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19
Q

Who came up with the LMS method?

A

Cole, 1998

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20
Q

What is the LMS method?

A
  • splits data into narrow age groups

- summarises skew weight distribution in each group

21
Q

What are the variables in LMS method?

A
  • Power transform λ
  • mean μ
  • coefficient of variation σ
22
Q

Why is it called LMS method?

A
L = curve for λ
M = curve for μ
S = curve for σ
23
Q

What is the formula for the LMS method

A

Centile(100α) =M x (1+LSzα)^(1/L)

24
Q

What is the formula for SD score from LMS method?

A

SD score = (measurement /M)^(L) − 1 DIVIDED BY (LS)

25
Who came up with Cole-green LMS method?
peter green, 1988
26
Why was the Cole-green method formulated?
proposed to use maximum penalised likelihood to improve LMS method - elegantly avoids arbitrary age groupings - now the STANDARD METHOD
27
How many countries use LMS method?
40
28
What did the British 1990 chart include?
- Weight - Height/length - BMI - Head circumference - waist circumference
29
What did the Personal Child Health Record (PCHR) include?
- weight - length/height - head circumference
30
what is the diff between growth reference and growth standard?
``` reference = shows how children DO growth standard = shows how children SHOULD grow, based on healthy reference population ```
31
When did WHO publish the current growth standard?
2006
32
What does the WHO growth standard include?
- sample breast-fed infant and children of non-smoking, non-deprived mothers from six countries (USA, norway, india, ghana, brazil, oman) - very similar linear growth patterns in all centres - chart describes optimal not average growth - suitable for all children
33
What does the length graph of the WHO standard growth show?
- similar length across sites | - growth potential is independent of ethnicity
34
What is the comparison of the British 1990 and the WHO standard weight chart for breast-fed infants?
British = 50:50 breast-fed and formula-fed infants WHO = entirely on breast-fed infants
35
What explains both relevance and irrelevance of using British 1990 charts?
- for height, it's accurate for current children - little sign of secular trend - for weight, and BMI, it's out of date though - and the centiles for weight and BMI no longer feasible on any chart
36
What does the UK-WHO chart development include?
- WHO charts from age 2 weeks to 4 years - continues using British 1990 from age 4-20 years and birth and pre-term data - RCPCH design charts and produce educational materials - developed by expert group and tested in focus groups of staff and parents
37
What is obesity again?
form of abnormal growth, malnutrition | - excess body fat
38
What is used to measure fat?
simple anthropometry - weight - weight for height - BMI - waist circumference
39
What is the purpose of BMI chart?
important for both clinical and public health
40
What are the centiles used in the BMI chart?
- 91st and 98th centile as the clinical cut-off - 85th and 95th for public health monitoring (but this is not on the chart) (P.s. IOTF international cut-offs for overweight and obesity included)
41
What does the waist circumference chart include and exclude?
- BMI ignores body composition (weight shifting between muscle and fat not detected) - waist circumference useful measure of abdominal fat (subcutaneous and internal)
42
What initially happened in the child BMI history?
- all the definitions of obesity from published papers had varying specification reference sample and centile cut-off - cannot compare across studies - hence NEED UNIFYING INTERNATIONAL REFERENCE
43
What is the proposal of the International Obesity Task Force (IOTF)?
- use BMI centiles to assess childhood overweight/obesity - centiles to pass through 25-30kg/m2 at 18yo - pool centiles from 6 large national surveys (brazil, britain, netherlands, hong kong, singapore, USA)
44
What was the outcome for IOTF?
- established standard definition for child overweight and obesity - body mass index cut-off to define thinness - BMI made cut-offs for thinness, overweight, and obesity
45
What did the national child measurement programme include?
- BMI of children in reception age 4-5 and year 6 (age 10-11) - assessed using 91st and 98th british 1990 centiles - parents told if child overweight/obese
46
Why should childhood obesity be monitored?
- prevalence high and strong - BMI and waist charts becoming out of date - charts need to be frozen so cut-off does not rise which prevalence - childhood fatness is a poor predictor of adult fatness - little value in targetting individuals unless severely obese - high BMI itself insufficient reason for obesity referral
47
What is the mean age at peak height of the modelling height puberty chart?
12-14 years
48
Why is the SITAR used to model growth curves?
adjust size, timing, and rate of puberty to superimpose individual curves - summaries the chaos of pubertal growth in just 3 parameters per child - efficiently estimates mean growth curve - useful for life course studies to relate early growth to later adverse outcome