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  1. 1. Growth & Development in Adolescence KN AGARWAL , President Healthcare & Research Association for Adolescents E mail : [email_address]
  2. 2. Growth & Development in Adolescence <ul><li>Succession of events in development of secondary sexual characteristics during puberty is consistent. </li></ul><ul><li>There is individual variation in the age of onset, duration and tempo of Growth. </li></ul>
  3. 3. Ethnic & Sibling variability in the onset and duration of Puberty <ul><li>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. </li></ul><ul><li>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) </li></ul>
  4. 4. Puberty encompasses- - Somatic Growth & Sexual development <ul><li>Adolescent growth spurt, </li></ul><ul><li>Development of secondary sexual characteristics.   </li></ul><ul><li>Attainment of fertility. </li></ul><ul><li>Establishment of individual sexual identity.   </li></ul><ul><li>Timing for Puberty onset has wide variability- </li></ul><ul><li>Girls- 8-12 years and Boys- 9-14 years of age. </li></ul>
  5. 5. Adolescent Growth Spurt <ul><li>Begins distally with enlargement of Hand and Feet, followed by the Arms & Legs and finally by the Trunk and Chest. </li></ul><ul><li>2. Larynx, pharynx and lungs—Voice </li></ul><ul><li>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. </li></ul>
  6. 6. Puberty -GIRLS <ul><li>First sign of ovarian estradiol secretion is breast development “Thelarche”.SMR-B-2 (Breast budding)- GROWTH IN HEIGHT. </li></ul><ul><li>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. </li></ul><ul><li>Change in body shape </li></ul><ul><li>Growth under arm hair followed by secretion </li></ul><ul><li>Menarche follows PHV by 14-18 months. </li></ul><ul><li>Adult size breast </li></ul>
  7. 7. Development of breast and pubic hair in girls - (Indian Data) <ul><li>Development of breast and pubic hair in girls - </li></ul><ul><li>Sexual maturity Breast Pubic hair (Mean age = 13.6yr) </li></ul><ul><li>Stages (SMR) </li></ul><ul><li>1. Preadolescent Pre-adolescent </li></ul><ul><li>2. Bud stage and </li></ul><ul><li>papilla elevated sparse lightly pigmented straight </li></ul><ul><li>as small mould (10.2 yr) around medial border of labia (22%) </li></ul><ul><li>3. Areola enlarged no contour darker, more and curly + (92%) </li></ul><ul><li>separation(11.6 yr) </li></ul><ul><li>4. Areola and papilla form secondary coarse curly </li></ul><ul><li>mound (13.6 yr) abundant (98.8%) </li></ul>
  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.
  9. 10. Puberty- BOYS <ul><li>Adrenarche is the ONSET & CONTINUITY of male PUBERTY </li></ul><ul><li>Testosterone/dihydrotestosterone are needed in large concentration to initiate “GH” via the androgen receptors. (Thus later than girls by 1-2 yr). </li></ul><ul><li>Initiation testicular volume > 4 ml; maximum growth “PHV” (10-11 cm /year) attained at Testicular volume 10-12 ml. (During SMR- G 3-4). </li></ul><ul><li>Testosterone –Deepens the voice and increases body muscle mass (lean body mass). </li></ul>
  10. 13. Development of genitals and pubic hair in boys- <ul><li>B. SMR Penis Scrotum & testes Pubic hair </li></ul><ul><li>1. Preadolescent Testes <4 ml none </li></ul><ul><li>2. Slight or no Enlarged darker scrotum scanty long (60%) </li></ul><ul><li>enlargement(11.3 yr) pigmented Testes>4mm </li></ul><ul><li>3. Longer (12.8 yr) Testes 6-8 ml dark, small, curling +(97%) </li></ul><ul><li>4. Larger, glans + Testes 10-12 ml resemble adult type but less in </li></ul><ul><li>breadth increased scrotum dark quantity and curls(99%) </li></ul><ul><li>(14.1 yr) </li></ul><ul><li>5. Adult size Testes 12 ml spread to medial surface of thigh </li></ul><ul><li>(16.4 yr) </li></ul><ul><li>Facial hair 14.8 yr . </li></ul>
  11. 14. Adolescent Growth Spurt <ul><li>Adolescence Growth - Period extends for 2.5 to 3 years; to cross Sexual Maturity stages 2-5. </li></ul><ul><li>Height gain is 27-29cm in boys & 24-26cm in girls; (1 cm height will need 4500 Kcal) </li></ul><ul><li>Weight gain in both 25-30 kg. </li></ul>
  12. 15. Bone Growth- Completes in Adolescence <ul><li>Quantitatively important bone mineral accretion occurs-increase in bone density during SMR-2 to 4(Cortical bone growth ). </li></ul><ul><li>Bone mineral density- 50% completes during first month of life to puberty onset; 30% in puberty and 20% in late adolescence to adult. </li></ul><ul><li>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 </li></ul>
  13. 16. Brain Growth in Adolescence <ul><li>Early Childhood- Maximum Brain grows as “Frontal circuits”- related to organization and planning. </li></ul><ul><li>Adolescence- Brain grows in the rear of the brain- linked more to language learning and spatial understanding. Thus brain development continues. </li></ul><ul><li>Myelination of the prefrontal cortex continues in adolescence. </li></ul>
  14. 17. SEXUAL DIMORPHISM – <ul><li>Shoulder growth in boys and hip growth in girls. </li></ul><ul><li>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 </li></ul><ul><li>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. </li></ul>
  15. 18. Sexual Dimorphism in Fat Distribution
  16. 19. Growth Monitoring during Adolescence
  17. 20. Assessment stages of SMR
  18. 21. Somatic growth <ul><li>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. </li></ul><ul><li>Cole et al 2000. BMI curves lost sensitivity in puberty. </li></ul><ul><li>Already said sexual growth varies in onset and duration- ethnic, individual & sibling. . </li></ul>
  19. 22. Growth pattern- variations <ul><li>Asian children- Chinese, Japanese, Korean, Taiwanese and Indian have similar linear growth-max difference 1 cm at 17 yr age. </li></ul><ul><li>NCHS and Europeans are taller by >7cm at 50 th and 97 th centile at 17 yr. </li></ul><ul><li>BMI is lower in American-Indians </li></ul>
  20. 25. How to Measure - somatic growth in adolescence <ul><li>Assess sexual maturity. </li></ul><ul><li>Ht,wt, BMI, SFT for age in relation to Sexual Maturity. </li></ul><ul><li>BMI ( kg/m 2 )- “Adolescence”.- SMR related -BMI . </li></ul><ul><li>SFT -triceps+biceps sub scapular + suprailiac in relation to SMR </li></ul><ul><li>Waist/hip ratio >0.8 women; 0.9 men. </li></ul>
  21. 26. REGIONAL DISTRIBUTION OF FAT <ul><li>Central Obesity - Excess abdominal fat(Android)-more associated with hyperglycemia, hyperlipidemia, increased triglycerides, hypertension seen more in South Indians &South Asians </li></ul><ul><li>Peripheral fat around body(Gynoid)- is associated with less morbidity & mortality </li></ul>
  22. 27. For comparison <ul><li>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. </li></ul><ul><li>2. Virani 2005; Ann Hum Biol-Pondicherry 40 yr data-secular growth in 20 yr has plateaued. Indians are shorter than Europeans. </li></ul>
  23. 28. Agarwal’s data 1989-91. <ul><li>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. </li></ul><ul><li>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. </li></ul>
  24. 29. Indian Children – BMI Data
  25. 30. Indian Children – BMI Data
  26. 31. Indian Children Ht & Wt Data
  27. 32. Indian Children Ht & Wt Data
  28. 33. . <ul><ul><ul><li>No age period could be identified for peak height velocity </li></ul></ul></ul><ul><ul><ul><li>Height gain was similar to affluent Indian children in adolescent growth spurt. </li></ul></ul></ul><ul><li>Deficit of early life in height was not corrected. </li></ul><ul><ul><ul><li>Weight gain was 38% of the affluent Indian . </li></ul></ul></ul>Puberty – in Undernourished
  29. 34. Undernourished- early life to adolescent ICMR-1982-96 (Agarwals) <ul><li>Boys had delayed maturation of: </li></ul><ul><li>Genitals by 1.54 yr; </li></ul><ul><li>Pubic hair by 0.82 yr and </li></ul><ul><li>Axillary hair by 0.65 yr . </li></ul><ul><li>Testicular vol. was similar. </li></ul><ul><li>Girls had delayed breast development by 2.19 yr. </li></ul><ul><li>Menarche was delayed by 0.82 yr </li></ul>
  30. 35. Undernourished Adolescents until 17.5 yr of age (To achieve linear growth) <ul><li>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. </li></ul><ul><li>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). </li></ul>
  31. 36. Higher mental functions- undernourished adolescents <ul><li>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). </li></ul>
  32. 37. Soft neurological signs- undernourished adolescents <ul><li>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. </li></ul>
  33. 38. Higher mental functions- undernourished adolescents <ul><li>Reaction time studies by Audio-visual RT apparatus and electromyograph:- showed affects on perceptual abilities, information processing and analytical capabilities (Agarwals-I J M R; 1998). </li></ul><ul><li>Those who became normally nourished still had raised RT, due to early life UN. </li></ul>
  34. 39. BRAIN- MRI studies-in undernourished Adolescent <ul><li>MRI and cognitive evoked potential studies - </li></ul><ul><li>Frontal lobes - Size was reduced & </li></ul><ul><li>Asymmetry of anterior as well as posterior lobes was less pronounced. </li></ul><ul><li>P3 latency was normal, but the P2 and P3 amplitudes were higher suggesting neuronal compensation. </li></ul><ul><li>(Agarwals-Nutr Res 1996). </li></ul>
  35. 40. <ul><li>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. </li></ul><ul><li>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. </li></ul>LESSONS IN THIS AGE GROUP:
  36. 41. Other nutrition related adolescent health issues- <ul><li>Lesions of Atherosclerosis begin to accelerate . </li></ul><ul><li>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. </li></ul><ul><li>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. </li></ul>
  37. 42.   Extremes of nutrition intake <ul><li>i) Overeating resulting in overweight and obesity; Induce rapid growth and early bone maturation; mestural functions; hypertension, diabetes, hyperlipidemia etc. </li></ul><ul><li>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. </li></ul>
  38. 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?
  39. 44. Energy/ Protein/ Fat <ul><li>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 </li></ul><ul><li>Protein 12-14% of energy- Boys 0.34g/cm ht. Girls 0.28g/cm ht. </li></ul><ul><li>Fat -<30% of total Kcal;7% saturated/ 10% polyunsaturated and 10% monounsaturated fat. Cholesterol ideally 200mg/day. </li></ul>
  40. 45. Cont.-Natl. Acad Sci USA-1997-98 <ul><li>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 </li></ul><ul><li>Vitamin C-Collagen synthesis </li></ul><ul><li>Vitamin D for Ca absorption. </li></ul>
  41. 46. THANKS <ul><li>Welcome to write : e-mail </li></ul><ul><li>[email_address] </li></ul>