Important growth parameters/dimensions: (1) Body proportion — compare with self, (2) Growth record — compare with past, (3) Comparison with other babies ^[1]

The lecture emphasizes that just looking at a child is insufficient — you need bedside examination to identify features like marked wasting over the buttock ^[1]. This is high yield because examiners may show a clinical photograph and ask you to identify wasting.

Z-score = statistical measurement of a score's relationship to the mean. Z-score of 0 = same as mean. Can be positive or negative, indicating standard deviations above or below the mean. ^[1]

In the slide's cross-sectional EAP-ECDS graph, mean cognitive score rose across height-for-age groups and was lower in the stunted group (P < 0.001). ^[1]

This is an association, not proof that short stature itself caused the developmental difference. Height-for-age is also a marker for antenatal factors, recurrent infection, diet, poverty and caregiving environment. The clinical lesson is to assess growth and development together and intervene on modifiable risks—not to infer an individual child's cognitive potential from height. ^[11]

Failure to Thrive:

• Failure of expected growth in children younger than 3 years
• Downward crossing of two percentile lines in weight over 6 months ^[1]

The slide's “two percentile lines over 6 months” is a useful historical exam phrase, but it is not a universal definition. NICE uses centile spaces and varies the threshold by birthweight: a fall of ≥1 space if birthweight was < 9th centile, ≥2 spaces if 9th–91st, ≥3 spaces if > 91st, or current weight < 2nd centile. Confirm measurement technique, plot weight and length/height, review the trajectory, and assess the child rather than labelling from one number. ^[12]

The lecture organizes causes by the processing of nutrition ^[1]:

FTT = Problem with getting calories in, breaking them down, using them, keeping them, or needing too many

• Verify serial measurements and chart choice; correct age for prematurity when appropriate.
• Take a medical, developmental and psychosocial history plus a detailed 24-hour feeding/eating history.
• Observe a feed or meal with an appropriately trained clinician when milk transfer, swallow safety, technique or interaction is uncertain.
• Examine hydration, fat and muscle stores, oedema, oral cavity, cardiorespiratory system, abdomen, skin/hair and development.
• Use targeted tests only when the history/examination indicates them; NICE specifically highlights urine infection and coeliac testing (once gluten has been introduced), rather than a blanket “FTT panel.” ^[12]

Coordinated sucking and swallowing → Gastric emptying → Intestinal motility → Secretions (salivary, gastric, pancreatic, hepatobiliary) → Enterocyte function (enzyme synthesis, absorption, mucosal protection) → Metabolism of digestion products → Expulsion of waste ^[1]

Fetal GI tract is exposed to constant passage of amniotic fluid containing growth factors, hormones, enzymes, and immunoglobulins → these play a role in mucosal differentiation, GI development, swallowing, and intestinal motility ^[1]

The gut of the newborn must transition from continuous amniotic fluid passage to digesting large quantities of intermittent boluses of milk ^[1]

GI peptides are found in venous cord blood at birth at levels similar to fasting adults. In fetal distress, gut peptides are elevated → may account for passage of meconium (meconium-stained liquor; MSL) ^[1]

Pancreatic function is relatively deficient at birth. Mature levels of pancreatic enzymes are not achieved until late infancy. Pancreatic amylase activity increases after 4–6 months. Lipase levels do not approach adult efficiency until about 6 months. ^[1]

Upper GI:

Esophageal motility is decreased. LES is primarily above the diaphragm. LES pressure is less for first months. Gastric emptying may be delayed. ^[1]

Reflux is common in infancy, but the old “weak LES” explanation is incomplete: transient LES relaxations, liquid diet, short oesophagus and frequent feeds contribute. Distinguish physiological regurgitation in a thriving infant from red flags such as bilious/bloody vomiting, forceful vomiting, dysphagia, aspiration, pain, dehydration or faltering growth.

Intestinal:

Intestinal motility is more disorganized. Prolonged transit time in upper intestines may improve absorption. Rapid emptying of ileum and colon may reduce time for water and electrolyte absorption → increased risk of dehydration. ^[1]

Limited ability to concentrate urine in first year due to immaturities of nephron and pituitary. Potential renal solute load is determined by nitrogenous end products of protein metabolism, Na, K, P, Cl. ^[1]

Prolactin → milk production; Oxytocin → milk ejection (let-down reflex) via myoepithelial cell contraction. Oxytocin also causes uterine contraction. ^[1]

The slide diagram shows the neuroendocrine reflex arc ^[1]. A useful correction is that prolactin from the anterior pituitary drives milk synthesis by alveolar epithelial cells, whereas oxytocin from the posterior pituitary contracts myoepithelial cells for milk ejection:

Infant suckling → Hypothalamus → Pituitary gland
  ├─ Prolactin → Lacteal / alveolar cells → Milk production
  └─ Oxytocin → Myoepithelial cells → Milk ejection (let-down)
              → Uterus → Uterine contraction

Energy: 67 kcal/100 mL

• CHO: lactose, oligosaccharides
• Proteins: lactoferrin (LF), α-lactalbumin, β-casein, lysozyme; cytokines, antibodies
• Fat: LC-PUFA (DHA, AA, EPA)
• Micronutrients & trace metals
• Cells: macrophages, neutrophils, lymphocytes ^[1]

The slide infographic's “over 400” count is promotional rather than a stable scientific classification. Human milk contains a changing mixture of nutrients, oligosaccharides, enzymes, immune cells and signalling molecules that varies across colostrum/mature milk, within a feed and between parents. When human milk is unavailable, contraindicated or not chosen, regulated infant formula is the appropriate nutritional alternative; families need practical, non-judgemental support for safe preparation.

The slide lists fatigue, stress, sleep disruption, transmissible infection, medication exposure and infant metabolic disease. Reframe these as reasons to offer skilled feeding, mental-health and practical support—not inherent harms or parental failure. ^[1]

Exclusive breastfeeding is recommended up to 6 months of age, with continued breastfeeding along with appropriate complementary foods up to 2 years of age or beyond ^[1]

Vitamin D supports calcium/phosphate homeostasis and skeletal mineralisation. ^[1]

Vitamin D deficiency during infancy is associated with:

• Growth retardation
• Skeletal deformities
• Hypocalcaemia and seizures in severe cases ^[1]

The slide's “over one billion” prevalence and broad immune/brain/psychiatric list depend on contested biochemical thresholds and observational associations. For a healthy child, the established clinical target is prevention of rickets and hypocalcaemia; low 25(OH)D associated with allergy, autoimmunity or psychiatric disease does not prove causation or that supplementation treats those diseases. The 2024 Endocrine Society guideline does not endorse routine 25(OH)D testing in healthy children and could not define a universal blood threshold for disease prevention. ^[20]

Rickets is one of the most common health problems related to vitamin D deficiency. It affects bone development in children and can cause bone pain, poor growth, and bone deformities. ^[1]

The image-heavy rickets slide illustrates the pattern to recognise ^[1]:

• Stunted growth
• Large forehead (frontal bossing)
• Spinal curvature and chest/rib deformity, including rachitic rosary
• Large abdomen
• Wide joints at elbow and wrist
• Widened wrists/ankles and bowed legs

Confirm suspected rickets with dietary/risk history and biochemical/radiographic assessment; not every bowed leg is nutritional rickets.

From first principles: Vitamin D supports intestinal calcium/phosphate absorption and mineralisation. Deficiency causes secondary hyperparathyroidism, renal phosphate wasting and failure of growth-plate/osteoid mineralisation; serum calcium may be maintained until deficiency is severe. This produces rickets in growing children (bowing, rachitic rosary, craniotabes, widened wrists) and osteomalacia after growth-plate closure.

Stunting reflects impaired growth and development from poor nutrition, repeated infection, and inadequate psychosocial stimulation. Vitamin D deficiency was identified as one risk factor for stunting. There is possible interaction with GH and IGF-1. ^[1]

The pictured paper is an observational association from a specific population. It does not establish vitamin D deficiency as a stand-alone cause of population stunting or prove a GH–IGF-1 treatment mechanism. Stunting is multifactorial; assess dietary calcium/vitamin D when indicated while also addressing total diet, recurrent disease and social/developmental context.

Vitamin D participates in immune signalling, but the slide's arrow “lower vitamin D → greater disease severity” converts correlation into causation. Inflammatory illness, reduced outdoor activity, diet, adiposity and treatment can all lower measured 25(OH)D. Do not use vitamin D to diagnose or treat allergy/autoimmune disease outside indication-specific guidance. ^[20]

Thresholds used in the local study:

• Sufficiency: > 50 nmol/L
• Insufficiency: 25–50 nmol/L
• Deficiency: < 25 nmol/L (serum total 25(OH)D) ^[1]

These were the study's analytical categories, not universal screening targets. Assay, population and clinical indication matter; avoid labelling a healthy child from a single threshold detached from local guidance. ^[20]

Risk factors: being a girl, low family income, multiparous mother, no vitamin supplementation, sunscreen application, maternal smoking history. A dose-response pattern exists — the more risk factors, the higher the probability of vitamin D insufficiency. ^[1]

Occurrence of multiple risk factors is the main reason for higher risk of vitamin D insufficiency among breastfed infants ^[1]

The lecture presents a dose-response table showing odds ratios for vitamin D insufficiency by breastfeeding status and cumulative risk factor count ^[1]:

The bar chart shows a steep association as risk factors accumulate, especially in exclusively breastfed groups, but the very large odds ratios likely have wide uncertainty and do not prove that breastfeeding caused deficiency. The practical response is supplementation, not discouraging breastfeeding.

Clinicians should provide practical supplementation instructions and identify children with additional risks. ^[1]

Do not prescribe deliberate direct sun exposure to an infant as a substitute for the recommended supplement; Hong Kong guidance advises shade because infants are vulnerable to UV injury. After 12 months, diet and safe outdoor activity usually contribute, with supplementation considered for limited sun exposure, dark skin/covering clothing, obesity, or liver/kidney and other relevant disease. ^[21]

The differential of short stature complements the FTT framework:

• Non-pathological ( > 90%): Genetic short stature, constitutional delay
• Pathological proportionate: Chronic illness (weight < height centile), endocrine (weight > height centile)
• Pathological disproportionate: Rickets, skeletal dysplasia

• 2024 MCQ Q92: 5-year-old girl, height < 3rd centile, webbed neck, low-set ears → Turner syndrome (syndromic short stature) ^[6]
• 2024 MCQ Q93: 7-year-old with CP, weight-for-height < 3%, chronic cough → choking on feeding (aspiration due to swallowing dysfunction → inadequate intake + recurrent aspiration pneumonia) ^[6]
• 2022 MCQ Q87: Dehydrated toddler with gastroenteritis → fluid management scenario (connects to the lecture's point about rapid ileal/colonic emptying → dehydration risk in infants) ^[7]