Growth & Development in Adolescence

1. Growth & Development in Adolescence KN AGARWAL , President Healthcare & Research Association for Adolescents E mail : adolcare@hotmail.com

2. Growth & Development in Adolescence • Succession of events in development of secondary sexual characteristics during puberty is consistent. • There is individual variation in the age of onset, duration and tempo of Growth.

3. Ethnic & Sibling variability in the onset and duration of Puberty • Ethnic- American Blacks enter puberty earlier than Whites: Breast Stage-2 at 8 years of age Blacks 48%(average age 8.8yr; PH- 8.7yr); Whites-only 15%(Av age 9.9yr; PH 10.7 yr). However, “Menarche” same time 12.2yr and 12.8yr, respectively. • Besides racial “Onset of Puberty” is different in an individual child, as well as in case of siblings (Ann Hum Biol 2005; et al Das Gupta)

4. Puberty encompasses- - Somatic Growth & Sexual development • Adolescent growth spurt, • Development of secondary sexual characteristics.   • Attainment of fertility. • Establishment of individual sexual identity.   • Timing for Puberty onset has wide variability- • Girls- 8-12 years and Boys- 9-14 years of age.

5. Adolescent Growth Spurt • Begins distally with enlargement of Hand and Feet, followed by the Arms & Legs and finally by the Trunk and Chest. 2. Larynx, pharynx and lungs—Voice 3. Androgens- a) Sebaceous glands- Acne, b) Optic globe-myopia and c) dental- jaw growth, loss of deciduous teeth eruption of permanent cuspids, premolars, and finally molars.

6. Puberty -GIRLS • First sign of ovarian estradiol secretion is breast development “Thelarche”.SMR-B-2 (Breast budding)- GROWTH IN HEIGHT. • Estradiol is a good stimulator of “GH” it doubles the growth velocity “PEAK HEIGHT VELOCITY’(9-10 cm / yr). Coincident with B-3. Follows B-2 by 1 yr. • Change in body shape • Growth under arm hair followed by secretion • Menarche follows PHV by 14-18 months. • Adult size breast

7. Development of breast and pubic hair in girls- (Indian Data) • Development of breast and pubic hair in girls- • Sexual maturity Breast Pubic hair (Mean age = 13.6yr) • Stages (SMR) • 1. Preadolescent Pre-adolescent • 2. Bud stage and • papilla elevated sparse lightly pigmented straight • as small mould (10.2 yr) around medial border of labia (22%) • 3. Areola enlarged no contour darker, more and curly + (92%) • separation(11.6 yr) • 4. Areola and papilla form secondary coarse curly • mound (13.6 yr) abundant (98.8%)

9. Menarche & linear growth The growth in the post menarche period is limited as girls can gain 5-6 cm in linear growth, only. Thus the maximum gain in height is pre-menarche in SMR- stages –B-2 & B-3.

10. Puberty- BOYS • Adrenarche is the ONSET & CONTINUITY of male PUBERTY • Testosterone/dihydrotestosterone are needed in large concentration to initiate “GH” via the androgen receptors. (Thus later than girls by 1-2 yr). • Initiation testicular volume > 4 ml; maximum growth “PHV” (10-11 cm /year) attained at Testicular volume 10-12 ml. (During SMR- G 3-4). • Testosterone –Deepens the voice and increases body muscle mass (lean body mass).

13. Development of genitals and pubic hair in boys- B. SMR Penis Scrotum & testes Pubic hair 1. Preadolescent Testes <4 ml none 2. Slight or no Enlarged darker scrotum scanty long (60%) enlargement(11.3 yr) pigmented Testes>4mm 3. Longer (12.8 yr) Testes 6-8 ml dark, small, curling +(97%) 4. Larger, glans + Testes 10-12 ml resemble adult type but less in breadth increased scrotum dark quantity and curls(99%) (14.1 yr) 5. Adult size Testes 12 ml spread to medial surface of thigh (16.4 yr) Facial hair 14.8 yr.

14. Adolescent Growth Spurt Adolescence Growth - Period extends for 2.5 to 3 years; to cross Sexual Maturity stages 2-5. Height gain is 27-29cm in boys & 24-26cm in girls; (1 cm height will need 4500 Kcal) Weight gain in both 25-30 kg.

15. Bone Growth- Completes in Adolescence • Quantitatively important bone mineral accretion occurs-increase in bone density during SMR-2 to 4(Cortical bone growth). • Bone mineral density- 50% completes during first month of life to puberty onset; 30% in puberty and 20% in late adolescence to adult. • 1 cm height gain needs Ca-20g; 30% gets absorbed (need 1300 mg/d Natl Acad. Sci. USA-97-98; AJCN 2005;-p 175). Take 4 cups of milk/d. DEFICIECY-FRACTURES

16. Brain Growth in Adolescence • Early Childhood- Maximum Brain grows as “Frontal circuits”- related to organization and planning. • Adolescence- Brain grows in the rear of the brain- linked more to language learning and spatial understanding. Thus brain development continues. • Myelination of the prefrontal cortex continues in adolescence.

17. SEXUAL DIMORPHISM – • Shoulder growth in boys and hip growth in girls. • They start puberty with similar fat and lean body mass content . Girls finally have 27% fat and boys 18%, from 16% . In boys gain in lean body mass is twice than the girls. But girls reduce LBM from 80% to 74%.These changes are due to sex hormones 3. Maintenance cost of lean body mass needs more energy .Thus boys have increased deposition of protein and minerals e.g. Fe/Ca/Zn. Sports- need oxygen & nutrition.

18. Sexual Dimorphism in Fat Distribution

19. Growth Monitoring during Adolescence

20. Assessment stages of SMR

21. Somatic growth • Caineo et al 2004; Ann Hum Biol. p-182- growth measured on daily basis has Stasis, steep changes, and continous growth period with wide individual variation. • Cole et al 2000. BMI curves lost sensitivity in puberty. • Already said sexual growth varies in onset and duration- ethnic, individual & sibling..

22. Growth pattern- variations • Asian children- Chinese, Japanese, Korean, Taiwanese and Indian have similar linear growth-max difference 1 cm at 17 yr age. • NCHS and Europeans are taller by >7cm at 50th and 97th centile at 17 yr. • BMI is lower in American-Indians

25. How to Measure - somatic growth in adolescence • Assess sexual maturity. • Ht,wt, BMI, SFT for age in relation to Sexual Maturity. • BMI (kg/m2)- “Adolescence”.- SMR related -BMI. • SFT-triceps+biceps sub scapular + suprailiac in relation to SMR • Waist/hip ratio >0.8 women; 0.9 men.

26. REGIONAL DISTRIBUTION OF FAT • CentralObesity- Excess abdominal fat(Android)-more associated with hyperglycemia, hyperlipidemia, increased triglycerides, hypertension seen more in South Indians &South Asians • Peripheralfat around body(Gynoid)- is associated with less morbidity & mortality

27. For comparison • Growth data – Somatic and Sexual growth data and the table prepared for ADOLESCENT children; Indian Pediatr 1992 & 2001(-The Growth-2003 CBS Publ. book) are the best available sets on affluent Indian children. 2. Virani 2005; Ann Hum Biol-Pondicherry 40 yr data-secular growth in 20 yr has plateaued. Indians are shorter than Europeans.

28. Agarwal’s data 1989-91. • CDC 2000, did not use the NHANES III –1998-99 data in growth curves, as obesity had significantly increased as compared to 1976-84 data. • Agarwal et al data on affluent children was collected during 1989-1991. In 2002; 2000 boys were re-examined in Delhi by us; there was no secular trend for height, but obesity was observed in 10% as compared to <1% in the 1989-1991 data. In Chandigarh in 2002; we observed that 52% boys and 44% girls had BMI > 95th centile.

29. Indian Children – BMI Data

30. Indian Children – BMI Data

31. Indian Children Ht & Wt Data

32. Indian Children Ht & Wt Data

33. . Puberty – in Undernourished • No age period could be identified for peak height velocity • Height gain was similar to affluent Indian children in adolescent growth spurt. • Deficit of early life in height was not corrected. • Weight gain was 38% of the affluent Indian .

34. Undernourished- early life to adolescent ICMR-1982-96 (Agarwals) Boys had delayed maturation of: • Genitals by 1.54 yr; • Pubic hair by 0.82 yr and • Axillary hair by 0.65 yr . • Testicular vol. was similar. • Girls had delayed breast development by 2.19 yr. • Menarche was delayed by 0.82 yr

35. Undernourished Adolescents until 17.5 yr of age (To achieve linear growth) • Maintain their vital functions by mobilising amino-acids from body muscles as demonstrated by increased serum enzyme activities i.e. LDH, ALP, AST, ALT, CK,CK-MB and CK-mm. • 31- phosphorus magnetic resonance spectroscopy showed that  -ATP and Pi were significantly increased at the cost of Pcr (Phosphocreatinine). These changes simulate myopathic status (Agarwals-Acta Peditar. 1994).

36. Higher mental functions- undernourished adolescents There was deficit in higher mental abilities related to personal and current information, orientation, mental control, logical memory, attention span, visual reproductive and associative learning: impairment in overall memory function in set formation and conditional learning (Agarwals-Acta Paediatr 1995).

37. Soft neurological signs- undernourished adolescents Soft neurological signs observed in preschool years persisted affecting repetitive speed movements more with higher degree of overflow and dysrythmia (Agarwals-Nutr Res 1995). Thus chronic UN affects brain function for finger coordination.

38. Higher mental functions- undernourished adolescents Reaction time studies byAudio-visual RT apparatus and electromyograph:-showed affects on perceptual abilities, information processing and analytical capabilities (Agarwals-I J M R; 1998). Those who became normally nourished still had raised RT, due to early life UN.

39. BRAIN- MRI studies-in undernourished Adolescent • MRI and cognitive evoked potential studies- Frontal lobes- Size was reduced & Asymmetry of anterior as well as posterior lobes was less pronounced. P3 latency was normal, but the P2 and P3 amplitudes were higher suggesting neuronal compensation. (Agarwals-Nutr Res 1996).

40. LESSONS IN THIS AGE GROUP: • No scientific study to show that nutrition supplement will improve the peak height velocity or the total height to compensate the stunting of early life. • N F I-study-(Agarwals- IJMR-1989;) children 6-8 yr of age followed for 2 yr (preadolescent undernourished) with (450-500 kcal & protein10-12g/ day), supplement given 172 days/yr.- did not show any height gain.

41. Other nutrition related adolescent health issues- • Lesions of Atherosclerosis begin to accelerate . • 1997-98 D. R. I.(Natl. Acad Sci, USA)-Folate 400ug/d-Prevents Atherosclerosis, clogging of arteries, heart attack, stroke-and reduce homocystein in smokersJAMA-1995 p1049-57. • Vitamin E-10 IU, Prevents Ca-deposit in Bl. Vs; neutralizes oxidation of bad LDL cholesterol-RBC membrane antioxidant in smokers. LANCET-1996;p786.Cont.

42. Extremes of nutrition intake • i) Overeating resulting in overweight and obesity; Induce rapid growth and early bone maturation; mestural functions; hypertension, diabetes, hyperlipidemia etc. • ii) for social pressure to reach cultural ideals of thinness - excessive dieting e.g. anorexia nervosa- 1% (more in girls) and bulimia-can lead to renal failure, secondary amenorrhea irregular heart rate, bone marrow hypoplasia, osteoporosis and dental erosion.

43. Dieting+ Intensive physical training for-thinness Alters hypothalamic-pitutary axis in adolescent girls – menstural functions altered and bone density reduced. Problems-Missing meals (girls)/reduced frequency/too much carbonated drinks, ice cream, french fries etc - low in macronutrient & micronutrients?

44. Energy/ Protein/ Fat • Needs around 136500Kcal as total cost of adolescent growth spurt.Peak energy needs- In girls with budding of mammary gland(SMR II-III) in boys(SMR-III-IV); 2200 and 3000Kcal resp/d • Protein 12-14% of energy- Boys 0.34g/cm ht. Girls 0.28g/cm ht. • Fat-<30% of total Kcal;7% saturated/ 10% polyunsaturated and 10% monounsaturated fat. Cholesterol ideally 200mg/day.

45. Cont.-Natl. Acad Sci USA-1997-98 • Recommends-B-complex group :Pyridoxine1.3mg, Riboflavin 1.3mg, Niacin 16mg,Thiamin 1.2mg folate 400ug pantothenic acid 5.0mg, Biotin 25ug, Choline 550mg, --Important for cellular energy metabolism • Vitamin C-Collagen synthesis • Vitamin D for Ca absorption.

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