Growth & Development in Adolescence KN AGARWAL ,

Growth & Development in Adolescence KN AGARWAL ,

Growth & Development in Adolescence KN AGARWAL , President Healthcare & Research Association for Adolescents E mail : [email protected] Growth & Development in Adolescence 1. Succession of events in development of secondary sexual characteristics during puberty is consistent. 2. There is individual variation in the age of onset, duration and tempo of Growth.

Ethnic & Sibling variability in the onset and duration of Puberty 1. 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. 2. 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) Puberty encompasses- - Somatic Growth & Sexual development 1. Adolescent growth spurt, 2. Development of secondary sexual characteristics.

3. Attainment of fertility. 4. Establishment of individual sexual identity. 5. Timing for Puberty onset has wide variability- 6. Girls- 8-12 years and Boys- 9-14 years of age. Adolescent Growth Spurt 1. Begins distally with enlargement of Hand and Feet, followed by the Arms & Legs and finally by the Trunk and Chest. 2. Larynx, pharynx and lungsVoice 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.

Puberty -GIRLS 1. First sign of ovarian estradiol secretion is breast development Thelarche.SMR-B-2 (Breast budding)- GROWTH IN HEIGHT. 2. 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. 3. Change in body shape 4. Growth under arm hair followed by secretion 5. Menarche follows PHV by 14-18 months. 6. Adult size breast Development of breast and pubic hair in girls- (Indian Data)

Development of breast and pubic hair in girlsSexual 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 separation(11.6 yr) 4. Areola and papilla form secondary mound (13.6 yr)

darker, more and curly + (92%) coarse curly abundant (98.8%) 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. Puberty- BOYS 1. 2.

3. 4. 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).

Development of genitals and pubic hair in boysB. SMR Penis Scrotum & testes Pubic hair 1. 2. Preadolescent Testes <4 ml Slight or no Enlarged darker scrotum enlargement(11.3 yr) pigmented Testes>4mm 3. Longer (12.8 yr) 4. Testes 6-8 ml Larger, glans + Testes 10-12 ml breadth increased scrotum dark (14.1 yr) 5.

Adult size Testes 12 ml none scanty long (60%) dark, small, curling +(97%) resemble adult type but less in quantity and curls(99%) spread to medial surface of thigh (16.4 yr) Facial hair 14.8 yr.

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 & 2426cm in girls; (1 cm height will need 4500 Kcal) Weight gain in both 25-30 kg. Bone Growth- Completes in Adolescence 1. Quantitatively important bone mineral accretion occurs-increase in bone density during SMR-2 to 4(Cortical bone growth). 2. Bone mineral density- 50% completes during first month of life to puberty onset; 30% in puberty and 20% in late adolescence

to adult. 3. 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 Brain Growth in Adolescence 1. Early Childhood- Maximum Brain grows as Frontal circuits- related to organization and planning. 2. Adolescence- Brain grows in the rear of the brain- linked more to language learning and spatial understanding. Thus brain development continues. 3. Myelination of the prefrontal cortex continues in adolescence.

SEXUAL DIMORPHISM 1. Shoulder growth in boys and hip growth in girls. 2. 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. Sexual Dimorphism in Fat Distribution 18

16 Triceps 14 Subscapular Girls SFT(mm) 12 Boys 10

Triceps 8 Subscapular 6 4 2 0 0 5 10 Age (Years)

15 20 Growth Monitoring during Adolescence Assessment stages of SMR Somatic growth 1. Caineo et al 2004; Ann Hum Biol. p-182growth measured on daily basis has Stasis, steep changes, and continous growth period with wide individual variation. 2. Cole et al 2000. BMI curves lost sensitivity in puberty.

3. Already said sexual growth varies in onset and duration- ethnic, individual & sibling.. 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 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. REGIONAL DISTRIBUTION OF FAT Central Obesity- Excess abdominal fat(Android)-more associated with hyperglycemia, hyperlipidemia, increased triglycerides, hypertension seen more in South Indians &South Asians Peripheral fat around body(Gynoid)- is associated with less morbidity & mortality

For comparison 1. 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. Agarwals 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. Indian Children BMI Data PERCENTILES FOR BODY MASS INDEX (BMI) (BOYS 2-18 YEARS) 30.00 adOlCARE 28.00 95th

26.00 85th B M I (K g /m ^ 2 ) 24.00 75th 22.00 50th 20.00

18.00 16.00 14.00 12.00 10.00 0 5 10

AGE 15 20 Indian Children BMI Data PERCENTILES FOR BODY M ASS INDEX (BM I) (GIRLS 2-17 YEARS) 30.00 adOlCARE 28.00 95th 26.00

B M I ( K g /m ^2 ) 24.00 85th 75th 22.00 50th 20.00 25th

18.00 10th 5th 16.00 14.00 12.00 10.00 0 2

4 6 8 10 AGE 12 14 16 18

20 Indian Children Ht & Wt Data PERCENTILES FOR HEIGHT AND WEIGHT (BOYS 2-18 YEARS) adOlCARE 200 97t h 90t h 75th 50t h 25t h 10th 3rd

180 HEIGHT (cm ) 160 140 120 100 97t h 80 WEIGHT(kg)

80 90t h 75t h 50t h 60 60 25t h 10t h 3rd 40

40 20 0 0 2 4 6 8

10 AGE 12 14 16 18 20 Indian Children Ht & Wt Data PERCENTILES FOR HEIGHT AND WEIGHT

(GIRLS 2-17 YEARS) adOlCARE 97th 180 90th 75th 50th 25th 10th 3rd 160 HEIGHT (cm )

140 120 100 80 80 97th 60 90th WEIGHT (kg)

60 75th 50th 40 25th 10th 40 3rd 20 0

0 2 4 6 8 10 AGE 12

14 16 18 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 . 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 Undernourished Adolescents until 17.5 yr

of age (To achieve linear growth) Maintain their vital functions by mobilising aminoacids 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). Higher mental functionsundernourished 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). Soft neurological signsundernourished 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. Higher mental functionsundernourished adolescents

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). Those who became normally nourished still had raised RT, due to early life UN. BRAIN- MRI studies-in undernourished Adolescent MRI and cognitive evoked potential studiesFrontal 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). 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. 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 cholesterolRBC membrane antioxidant in smokers. LANCET-1996;p786. Cont. 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. 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? Energy/ Protein/ Fat Needs around 136500Kcal as total cost of adolescent growth spurt.Peak energy needsIn 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. 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. THANKS Welcome to write : e-mail [email protected]

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