Adolescent Physical Development

8/10/2019 Adolescent Physical Development

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Adolescent Physical Development: Uses and Limitations of Growth Charts

Introduction

The second decade of life, from 10 to 0 years of a!e, coincides with the process ofadolescenceand is mar"ed #y n$mero$s physical chan!es% Growth and development thatocc$rs d$rin! p$#ertyaffects all #ody or!ans and systems% &Growin!' in #oth wei!ht and hei!ht(stat$re) is a characteristic feat$re of this sta!e of life, and the p$#ertal &!rowth sp$rt' is the onlypost*natal period in which there is normally an acceleration in the increase of #oth hei!ht andwei!ht% The !rowth sp$rt in hei!ht (&pea" hei!ht velocity') has an onset and d$ration that ishi!hly varia#le from individ$al to individ$al, and is affected #y !enetic, !ender and n$tritionalinfl$ences% +t is followed #y a rapid decrease in the rate at which stat$re increases as the finalad$lt hei!htis approached% The !rowth sp$rt in wei!ht is dependent on the #alance #etweenener!y (caloric) inta"e and o$tp$t% +f ener!y inta"e is si!nificantly less than o$tp$t, $nderwei!htres$lts if ener!y inta"e si!nificantly e-ceeds o$tp$t, overwei!ht or o#esity can res$lt% Thismod$le addresses practical $ses and limitations of the new CDC !rowth charts applied toadolescents% Three cases are presented to ill$strate "ey points%

Objectives

Upon completion of this mod$le, yo$ will #e a#le to:

Descri#e three feat$res of normal !rowth c$rves d$rin! adolescent development

List two differences #etween &early' and &late' developers in p$#erty

Apply data from !rowth charts to appropriately screen, assess and monitor adolescents

Estimated Time Needed to Complete This Module

To read thro$!h te-t: .0 min$tes

To read thro$!h te-t and complete e-ercises: /0 min$tes


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Normal Pubertal DevelopmentThe application of !rowth charts to adolescents re$ires an $nderstandin! of normal !rowth anddevelopment d$rin! p$#erty% ore than .0 years a!o, 2ames Tanner and associates #e!andescri#in! the normal physical chan!es that occ$r d$rin! p$#erty% Tanner has noted that &theonly thin! that is constant a#o$t p$#erty is chan!e'% 3esides the o#vio$s differences of the!enitalia and secondary se- characteristics #etween males and females, there are also

differences #etween individ$als who develop early compared to those who develop later in theirteena!e years% This conte-t of chan!e m$st #e appreciated when $sin! !rowth charts inadolescents%

Tanner and collea!$es serially meas$red and photo!raphed a lar!e n$m#er of normal 3ritishmales and females to determine the physical chan!es that adolescents e-perience as they !rowfrom #oys to men and from !irls to women% 4ive reco!ni5a#le sta!es of p$#ertal chan!es(called Tanner 6ta!es, or 6e-$al at$rity 7atin!s**67), have #een descri#ed for males andfor females% 4or #oys, the three physical elements of se-$al mat$rity ratin! are the si5e of thetestes, the len!th of the penis, and the development of p$#ic hair% The two physical elements ofse-$al mat$rity ratin! for !irlsare #reast and p$#ic hair development%

+n addition to the chan!es !enitalia and p$#ic hair, adolescents e-perience a se$ence ofevents d$rin! p$#erty% 4or !irls, a rapid increase in the velocity at which their stat$re increasesd$rin! the p$#ertal &!rowth sp$rt' (pea" hei!ht velocity) occ$rs a#o$t a year after the onset of#reast development, !enerally aro$nd a!e 1% This phase is represented in the !irls stat$re*for*a!e c$rve as a sli!ht $pward inflection point at a#o$t 10 years of a!e, followed #y a morerapid increase in stat$re $ntil a#o$t 1 years of a!e, when the slope of the stat$re c$rvereaches its ma-im$m% Another inflection point can #e seen aro$nd 18 years of a!e, when theslope of the stat$re c$rve noticea#ly falls downward and the c$rve event$ally flattens o$tentirely as the final ad$lt hei!ht is reached%

6how each of these points in a !raphic on the 90 thtile line: inflection $pward at 10 years old,pea" hei!ht velocity at 1 years of a!e, inflection downward at 18 years of a!e, final ad$lt hei!ht

#y 0 years of a!e% This wo$ld re$ire five consec$tive views of the same stat$re*for*a!e chartfor !irls, #$t wo$ld not re$ire the learner to clic" on anythin!% The effect wo$ld #e li"e addeds$ccessive overlays on a transparency, each &new' chart addin! a new element to the previo$schart: 1) stat$re*for*a!e c$rve with 90thtile hi!hli!hted, ) add arrow at $pward inflection point,at 10 years of a!e, 8) add arrow at pea" hei!ht velocity, at 1 years of a!e, .) add arrow atdownward inflection, at 18 years of a!e, 9) final ad$lt hei!ht, aro$nd 1; years of a!e% + wo$lds$!!est this #ein! one whole screen, not somethin! people scroll down to !et to% Alternatively,yo$ may want to have the screen split in two, with the te-t on the left and the chart on the ri!htthat follows the te-t%

3reast development #e!ins (thelarche) aro$nd 11 years of a!e, and menses !enerally #e!in(&menarche') a#o$t two years after the onset of #reast development, at an avera!e a!e of a#o$t

1%9 to 18 years of a!e% 7ecent data s$!!ests that !irls may #e e-periencin! thelarche earlierthan previo$sly tho$!ht, on avera!e aro$nd 10 years of a!e for white !irls and < years of a!efor #lac" !irls% =owever, a n$m#er of pediatric endocrinolo!ists have called the validity of thesest$dies into $estion and these st$dies have not demonstrated a dramatic decrease in the a!eof menarche% >Add the word &thelarche' #etween 10%9 and 11 years of a!e, and the word&menses' #etween 1%9 and18 year a!e span on the chart a#ove?% Altho$!h not demonstratedon the charts, it is "nown that earlier p$#ertal development is associated with more rapidincrease in stat$re and wei!ht than avera!e, while later p$#ertal development is associated witha less rapid increase in stat$re and wei!ht%


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6imilar to !irls, #oys demonstrate an $pward inflection in the slope of stat$re at the #e!innin! oftheir !rowth sp$rt, followed #y a more rapid increase in stat$re, #$t the pea" hei!ht velocityocc$r a#o$t years later than for !irls, aro$nd 1. years of a!e% Unli"e females, males cancontin$e to !row to the end of the stat$re c$rves at a!e 0, altho$!h the increment in hei!htafter a!e 1; is $s$ally not more than 1 cm% The increase in hei!ht in males is d$e to andro!ens

prod$ced #y the testes, so the !rowth sp$rt in stat$re is preceded #y an increase in the si5e ofthe testes% These same andro!ens also ca$se the penis to len!then and widen%

6how a !raphic similar to the one a#ove for !irls with the to 0 year old #oys stat$re*for*a!echart: 1) stat$re*for*a!e c$rve with 90thtile hi!hli!hted, ) add arrow at pea" hei!ht velocity, at1. years of a!e, 8) add arrow at final ad$lt hei!ht, aro$nd 0 years of a!e% Then add the word&testes enlar!e' aro$nd 11%9 years of a!e and penis len!thens and widens aro$nd 18 years ofa!e%

D$rin! p$#erty, there is not a distinct sp$rt in wei!ht !ain as there is in stat$re, and thevaria#ility of wei!ht is !reater than for stat$re, leadin! to a widenin! &spread' over time in wei!ht#etween the hi!her and lower percentiles #etween 10 and 0 years of a!e% +n addition, d$rin!

p$#erty the composition of the tiss$es that ma"e $p #ody wei!ht chan!es over time in differentways for females and males%

@arly in p$#erty, females slow their acc$m$lation of total #ody fat, #$t d$rin! their pea" hei!htvelocity they accelerate their acc$m$lation of fat and lean #ody tiss$e, leadin! to an increase inwei!ht that pea"s $st prior to menarche% After that time, the rate at which wei!ht is addedslows, with an inflection point aro$nd 18 years of a!e% There is a lar!e difference #etween therate at which wei!ht is !ained at the e-tremes of percentiles% 3etween the a!e of 1 and 18,!irls at the 9thtile !ain less than ; l#s, while those at the


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Clinical Pearls: Pubertal Growth and Developmentreast development% Tr$e #reast development in #oth females (thelarche) and males

(!ynecomastia) is d$e to !rowth of !land$lar tiss$e, not fat% 4or adolescents who are appear to#e developin! #reast tiss$e, it is important to differentiate #etween !land$lar tiss$e (firmer andsomewhat tender tiss$e immediately $nder the areola) and fat (increase in fat in the #reasttiss$e, alon! with fat in other sites of the #ody)% 6ome overwei!ht adolescents may not #e

developin! se-$ally, #$t merely increasin! the amo$nt of fat in their #reast tiss$e% +f a pre*p$#ertal !irl or #oy is already overwei!ht, sheEhe can #e e-pected to !ain wei!ht even morerapidly when sEhe event$ally does !o thro$!h p$#erty%

!ei"ht% 3etween ; and 1. years of a!e, !irls tend to !ain wei!ht more rapidly than#oys, #$t the 90thtile 3+ meas$res for !irls and #oys are nearly identical% A !irl at the 90thtile !ains fo$r times as m$ch wei!ht #etween 10 and 1. years of a!e as she does #etween 1/and 0 years of a!e (.0 compared to 10 po$nds)% After 1. years of a!e, wei!ht contin$es toincrease, #$t at a decreased rate% 3eca$se #oys have their !rowth sp$rt a#o$t two years laterthan !irls, the ma-im$m rate of wei!ht !ain for #oys is #etween 1 and 1/ years of a!e% A #oyat the 90thtile in wei!ht !ains a#o$t .9 po$nds over those fo$r years, while he !ains an

additional 0 po$nds #etween 1/ and 0 years of a!e%

#ei"ht% Until 10 years of a!e, #oys and !irls !row in stat$re at nearly identical rates%Aro$nd 10 years of a!e, !irls at the 90thtile #e!in to !row taller more rapidly than #oys% The!rowth rate for !irls contin$es to #e !reater than #oys #etween 10 and 18 years of a!e% After 18years of a!e, the hei!ht sp$rt of !irls !enerally is completed and the #oys hei!ht sp$rt is in itsearly phase% Therefore, #y 1. years of a!e #oys are taller than !irls, on avera!e% Girls!enerally !ain no more than inches in hei!ht after the onset of menstr$al periods% =owever,males can contin$e to !row in hei!ht in their early 0s% 3y the time that ad$lt hei!ht is reached,the 90thtile for hei!ht is a#o$t / inches hi!her for males than for females% Th$s, the avera!ead$lt male is a#o$t F0 inches and the avera!e ad$lt female is a#o$t /. inches tall%

Normal Chan"es in od$ Mass Inde% &MI' Durin" (dolescence

Trac)in" o* MI3+ decreases d$rin! early childhood, reaches a nadir (the so*called reboundpoint) #etween .and F years of a!e, and then increases to 0 years of a!e% These chan!es in 3+ referenceval$es with advancin! a!e reflect normal chan!es in #ody composition d$rin! p$#erty% 4at*free#ody mass increases in #oth se-es, #$t its acc$m$lation is more mar"ed in #oys than in !irlsafter 18 years of a!e% 3ody fat contin$ally increases in !irls d$rin! most of the second decade,while #oys tend to decrease fat after a!e 1.% The s$m total of chan!es in fat*free and fat #odymass res$lt in the n$merator (wei!ht), while the s$m total of the chan!es in stat$re res$lt in thedenominator (hei!ht)in the e$ation for 3+% These normal chan!es m$st #e considered

when interpretin! data for individ$al adolescents, as well as for !ro$ps of adolescents%

The increase in 3+ is nearly linear in #oys d$rin! the second decade of life in all #$t thehi!hest percentiles (in which the line #ecomes sli!htly conve- $pward) The 3+ percentiles foradolescent !irls, on the other hand, are all sli!htly conve- $pward% 2$st as wei!ht and hei!httend to follow a percentile &channel', so does 3+% This &trac"in!' of 3+ can #e $sed to identifychan!es in !rowth that may indicate an $nderlyin! pro#lem or call for some "ind of intervention%


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+ower ,an"es o* MI+n the lower ran!es, 3+ tends to increase more slowly in #oth adolescent #oys and !irls% At the9thtile, 3+ increases at the rate of a#o$t 0%9 $nitEyear d$rin! most of the second decade%

#i"her ,an"es o* MI+n the hi!her ran!es, 3+ tends to increase more rapidly in #oth #oys and !irls% At the


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Case -.: /se o* "rowth charts *or assessin" pre0pubertal "rowth durin" adolescence

andy is a 1 year old female who has #een a #allet dancer since a!e /% At her health

s$pervision visit, she wei!hs // l#s (8rdtile) and is 9; inches tall (9thtile)% =er 3+ is 18%;(B8rdtile for a!e)% 6he has no evidence of #reast or p$#ic hair development, and e-presses nointerest in &!rowin! $p' #eca$se she does not want to &!et fat'% 6he has heard her danceteachers ma"e comments a#o$t other st$dents in her dance class !ainin! wei!ht too $ic"ly%

6he eats a low*fat diet #eca$se her mother was fo$nd to have a hi!h cholesterol and Type ++dia#etes associated with moderate o#esity, wei!hin! 1F9 po$nds at /. inches tall% 4ather is aF0 inch tall competitive r$nner, who is a self*descri#ed &fitness fanatic'%

=er !rowth c$rves are shown, side #y side, stat$re on left and wei!ht on ri!ht% 6he was at the90thtile for stat$re and 9thtile for wei!ht till a!e 10: avera!e hei!ht, #$t thin% Then, the slopeof her wei!ht c$rve #e!an to decrease more than her stat$re c$rve% + wo$ld add points for heryearly chec"*$ps, so that the learner sees the c$rve on the chart, with all points #ein! on ornear the 90thtile for stat$re and 9thtile for wei!ht% =er 3+ chart co$ld #e shown #elow thestat$re and wei!ht charts% 6ince there were no 3+ charts availa#le $ntil this year, she will onlyhave one point on it, from this visit, at 18%;%

Disc$ssion% andys case ill$strates three "ey points in the application of !rowth charts topre*p$#ertal adolescents%

1) andy has not yet reached her ad$lt hei!ht, #eca$se she has not yet #e!$n p$#erty and hasnot !one thro$!h her !rowth sp$rt% 4inal ad$lt hei!ht can #e affected #y many factors, incl$din!n$trition and illness, #$t her genetic potentialwith respect to hei!ht, can #e estimated from her

mid-parental height formula: (4athers hei!ht H others hei!ht I 9) % +n andys case, that

wo$ld #e (F0H/.*9)J/.%9 inches for her e-pected ad$lt hei!ht% +f she were to contin$e to

!row alon! the 9thtile, her final ad$lt hei!ht wo$ld #e /%9 inches, inches less thanotherwise e-pected% Altho$!h this may not #e important to andy at this time, it may #ecomeimportant to her later% hen pointed o$t to adolescents, s$ch red$ction of !rowth potential may#e a motivatin! factor for adolescents to improve their n$trition% The data from the CDC !rowthcharts are an important element of her health s$pervisionassessment, #$t co$ld also #e $sedto motivate chan!in! her eatin! #ehavior to allow an adolescent to reach herEhis e-pectedstat$re% +mprovin! n$trition wo$ld not necessarily res$lt in increased stat$re,

) andys fall in wei!ht and hei!ht indicate that her !rowth has slowed more than e-pected,similar to what is called &fail$re to thrive' in yo$n!er children (lin" with Peters mod$le on thistopic)% This co$ld possi#ly d$e to inade$ate caloric inta"e relative to increased ener!y needsd$rin! p$#erty% +t definitely deserves attention, since it is not part of healthy !rowth anddevelopment at this a!e%

=er interest in #allet and in &not !rowin! $p', may have led to her limitin! her food inta"ethro$!h dietin!% Also, it is clear that she is hearin! messa!es from her dance teacher a#o$t not!ainin! wei!ht too $ic"ly% This may have started as early as 10 years of a!e, since her !rowthc$rves #e!an to fall off aro$nd that time% 4rom a clinical perspective, that #e a time when herpeers may have #e!$n p$#ertal development and &!rowin! $p', which co$ld incl$de !ainin!more than 10 po$nds of wei!ht ann$ally% The CDC !rowth charts can th$s #e $sed to identifythe effects of s$#tle chan!es in the diet that may not #e apparent in day*to*day livin!, especiallyin #$sy ho$seholds%


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8) =er family history of a mother who is overwei!ht and has diet*related medical complications,and a father who is a &fitness fanatic', are additional ris" factors for andy possi#ly developin!dysf$nctional eatin! ha#its, possi#ly even an eatin! disorder% Bright Futures in Practice:Nutritionemphasi5es a family*oriented approach to n$trition that is especially important wheneatin! pro#lems arise% An adolescents !rowth and development always needs to #e assessedin the conte-t of her family and her environment%

Case -1: /se o* "rowth charts to screen *or e%cessive wei"ht "ain durin" adolescence

2ose is a 19 year old male who has asthma and a decreased level of activity #eca$se of

e-ercise*ind$ced whee5in!% =is favorite activity is playin! video!ames on the comp$ter% =ishas had episodic health care, !enerally related to asthma attac"s% hen he enrolls in his hi!hschool health clinic, his wei!ht is 1/0 l#s (


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sho$ld #e screened for family history, #lood press$re, total cholesterol, lar!e chan!e in 3+over time and concerns a#o$t wei!ht% +f any of these factors are positive, an in*depth medicalassessment in indicated% An in*depth medical assessment is also indicated for adolescents

whose 3+ is


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Case -2: /se o* "rowth charts to monitor wei"ht *luctuation durin" adolescence

Don is an 1; year old male wants to lose wei!ht to ma"e his colle!e li!htwei!ht freshman

crew team, since he does not thin" he is !ood eno$!h to ma"e the heavywei!ht team% =e$nderwent early p$#erty and !ained a lar!e amo$nt of wei!ht #etween 11 and 18 years of a!e,which he maintained thro$!ho$t hi!h school% D$rin! those two years, his stat$re increased #y10 inches, from 9/ to // inches tall% =e has #een &!ettin! in shape for the season' #y eatin! a

#alanced, low*fat diet, and e-ercisin! re!$larly (aero#ic and resistance trainin!), and hasdropped his wei!ht from 00 to 1;0 l#s% =owever, he wants to decrease his wei!ht to 199l#s, ata hei!ht of F1 inches, so that he can try o$t as a li!htwei!ht%

6how his stat$re and wei!ht charts li"e in cases 1 and , and 3+ chart #elow, with earlyp$#ertal !rowth sp$rts and fall*off in wei!ht over past ei!ht months

Disc$ssion% Dons case ill$strates three "ey points in the application of !rowth charts to

adolescents whose wei!ht fl$ct$ates d$rin! adolescence%

1) Dons !oal of !oal of wei!hin! 199 l#s at F1 inches wo$ld res$lt in a 3+ of 1%/% This wo$ld#e a &healthier' 3+ than he had at 18 years of a!e (1F0 l#s and // inches, 3+ F%9)%=owever, the way in which an o#ese individ$al red$ces hisEher hi!h 3+ m$st #e e-aminedclosely, and every effort sho$ld #e made to maintain the lower 3+ once it is attained% There isevidence in ad$lts that havin! a 3+ fl$ct$ate #etween hi!h and lower val$es (&yo*yo') may #eassociated with !reater mor#idity and mortality than maintainin! a moderately elevated 3+% +tappears as if Don is approachin! &!ettin! in shape' $sin! healthy means of red$cin! ener!yinta"e and increasin! activity% =owever, attemptin! to reach an artificial !oal esta#lished #y acompetitive sport co$ld #e a pro#lem, if his athletic performance #ecomes compromised #y atoo*low wei!ht%

) 3eca$se the form$la for 3+ (wt in "! >ht in m?) does not consider #ody composition,

athletes who have a hi!her than avera!e amo$nt of lean #ody mass (m$scle) may have ahi!her than e-pected 3+, #$t not #e o#ese% This co$ld res$lt in a &false positive' la#el ofo#esity, $sin! 3+ c$toffs% =owever, it is $s$ally possi#le to identify on physical e-aminationadolescents whose hi!h 3+ is d$e to e-treme m$sc$larity rather than e-cessive fat tiss$e%The $se of triceps s"infold thic"ness in this sit$ation can help confirm the clinical impression ofnormal #ody fat stores (=imes, et al% Nalidity of anthropometry in classifyin! yo$ths as o#ese%+nt 2 #es 18:1;8*1


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,e*erences

3arlow 6@, Diet5 =% #esity @val$ation and Treatment: @-pert Committee 7ecommendations%Pediatrics 1

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Adolescent Physical Development