Influence of body com p sition on the bone m ass of
postm enopausaI w om en
U n i d a d e d e D i a g n ó s t i c o e D e n s i t o m e t r i a Ó s s e a , D e p a r t a m e n t o d e F i s i o l o g i a e B i o f í s i c a d o I C B - U S P à n d D e p a r t a m e n t o d e G i n e c o l o g i a d e O b s t e t r í c i a d a S a n t a C a s a d e S ã o P a u l o - S ã o P a u l o , B r a z i lA im s :T o in v e s tig a te th e in flu e n c e o f b o d y w e ig h t (B W ), fa t m a s s (F M ) a n d le a n m a s s (L M ) o n th e b o n e m in e ra l d e n s ity (B M D ) o f s e v e ra l a re a s o f th e s k e le to n . P a rtic ip a n ts : S ix ty o n e w h ite p o s tm e n o p a u s a l w o m e n (5 0 .1:t4 .8 y e a rs ). M e a s u re m e n ts : M e a s u re m e n t o f B M D b y d u a l e n e rg y x -ra y a b s o rp tio m e try . T h e re s u lts w e re a n a ly z e d b y lin e a r re g re s s io n a n d th e s lo p e s o f e a c h c u rv e w e re c o m p a re d . R e s u lts : T h e re s u lts s h o w e d th a t th e c o rre la tio n s b e tw e e n B W , F M a n d L M to B M D w e re p o s itiv e , w h ils t th e c o rre la tio n s b e tw e e n a g e a n d y e a rs s in c e m e n o p a u s e to B M D w e re n e g a tiv e . L M w a s th e m a in fa c to rth a t in flu e n c e d B M D in a lm o s t a li a re a s . C o n c lu s io n s : F M a n d L M p re s e n t a p o s itiv e e ffe c t o n B M D , a lth o u g h L M is th e m a in d e te rm in a n t o f b o n e m a s s . M o re o v e r, h ig h e r v a lu e s o f L M a n d F M p re s e n t a p ro te c tiv e e ffe c t a g a in s t th e re d u c tio n o f B M D c o m b in e d w ith m e n o p a u s e . T h e re fo re p o s tm e n o p á u s a l w o m e n w ith lo w B W , e s p e c ia lly lo w L M , p re s e n t s e rio u s ris k fo r d e v e lo p in g o s te o p o ro s is .
U N IT E R M S : B o d y c o m p o s itio n . B o n e m a s s . B o n e m in e ra l d e n s ity . P o s tm e n o p a u s e .
IN T R O D U C T IO N .
O
b o n e m a ss a n d d e te rio ra tio nste o p o ro sis is a d ise a se c h a ra c te riz e do f m ic ro a rc h ite c tu reb y re d u c e d o f b o n e tissu e , le a d in g to th e in c re a se o f b o n e fra g ility a n d fra c tu re riskl. T h is p a th o lo g y is in c re a sin g ly re a c h in g a h ig h p e rc e n ta g e o f th e w o rld 's p o p u la tio n , c o n sid e rin g th a t its c lin ic a I p re se n ta tio n in c lu d e s fra c tu re s, e sp e c ia lly th e C o lle s, p ro x im a l fe m u r a n d v e rte b ra e2•
P re v e n tio n h a s b e e n re c o g n iz e d a s th e b e st a p p ro a c h to th is d ise a se3
, w ith . th e sk ill o f p re d ic tin g th e o c c u re n c e o f
A d r e s s fo r c o r r e s p o n d e n c e :
A n to n io C . B ia n c o
D e p a rta m e n to d e F is io lo g ia e B io fís ic a , IC B -U S P A v . P ro f. L in e u P re s te s , 1 5 2 4
S ã o P a u lo /S P - B ra s il - C E P 0 5 5 0 8 -9 0 0
o ste o p o ro sis b e in g o f th e u tm o st im p o rta n c e in th e se le c tio n o f p a tie n ts fo r p re v e n tiv e tre a tm e n r. T h e d e v e lo p m e n t o f p re c ise te c h n iq u e s fo r m e a su rin g b o n e m a ss h a s id e n tifie d p a tie n ts w h o p re se n t h ig h risk fo r o ste o p o ro tic fra c tu re s. F u rth e rm o re , th e se te c h n iq u e s h a v e p e rm itte d th e in v e stig a tio n o f se v e ra l fa c to rs w h ic h in flu e n c e b o n e m in e ra l d e n sity (B M D )5 .
V a rio u s p ro sp e c tiv e stu d ie s h a v e sh o w e d th a t th e risk fo r fra c tu re s p ro g re ssiv e ly a n d c o n tin u a lly in c re a se s a s B M D d e c re a se s6-8• D e c re a se d b o n e m a ss d e te c te d d u rin g
a g in g c a n b e th e c o n se q u e n c e o f lo w p e a k b o n e m a ss re a c h e d d u rin g y o u th9
, a s w e ll a s o f ra p id d e te rio ra tio n o f
b o n e m a sslO
, o r b o th o f th e m . In th e c a se o f w o m e n , th e d e c re a se in b o n e m a ss b a sic a lly h a p p e n s d u e to a g in g , n o rm a l fo r b o th se x e s, a n d d e fic ie n c y o f e stro g e n a sso c ia te d w ith th e m e n o p a u sell
. B e sid e s th e se tw o fa c to rs, b o n e lo ss se e m s to b e in flu e n c e d b y se v e ra l fa c to rs lik e ra c e , h e re d ity , p h y sic a l a c tiv ity a n d a lso b o d y c o m p o sitio n I2-14• H o w e v e r, h a rd ly a n y th in g is k n o w n a b o u t th e in flu e n c e o f th is la tte r
M A R O N E , M .M .S .; G O U V E IA , C .H .A .; L E W IN , S .; M A L V E S T IT I, L .F .; B IA N C O , A .C . -In flu e n c e o f b o d y c o m p o s itio n o n th e b o n e m a s s o f p o s tm e n o p a u s a l w o m e n
facto r o n b o n e 1 0 ssI5 -1 7 .M an y stu d ies h av e d em o n strated th at b o d y w eig h t is p o sitiv ely asso ciated w ith b o n e m ass
l8-2 1 ,b u t n ev erth eless th ere is a certain co n tro v ersy w ith reg ard to th e in d ep en d en t effects o f its m ain co m p o n en ts: lean an d fatty tissu e. S o m e stu d ies h av e sh o w ed th at th e q u an tity o f fat is th e m ain d eterm in an t o fb o n e d en sity 2 1 ,2 2 ,w h ile o th ers co n sid er it to b e th e lean tissu e2 3 . T h e cu rren t stu d y aim s: (i) to id en tify w h at actio n th e co m p o n en ts o f so ft, lean an d fatty tissu es h av e o n th e b o n e m ass o f w o m en in th e p o stm en o p au sal p erio d , u tilizin g th e d u al en erg y X -ray ab so rp tio m etry m eth o d ; an d (ii) to ev alu ate th e effects o f b o d y co m p o sitio n o n th e d ecrease in b o n e m ass d u e to th e m en o p au se.
P A T I E N T S A N D M E T H O D S
Patients
S ix ty o n e p o stm en o p au sal w o m en w ere stu d ied . M en o p au se w as d efin ed as cessatio n o f m en stru atio n fo r at least 6 m o n th s, an d th e clim acteric p erio d w as lim ited to 1 0 y ears. A ll th e w o m en w ere w h ite an d p resen ted 5 0 .1 :t4 .8 y ears o f ag e. N o o n e su ffered fro m sy stem ic d iseases o r w as u sin g an y m ed icam en t w h ich co u ld in flu en ce th e b o n e o r so ft tissu es. T h is p o p u latio n w as recru ited fro m am o n g G y n eco lo g y o u tp atien ts, an d all p atien ts v o lu n tarily ag reed to p articip ate in th is stu d y .
Bone Mineral Oensity (BMO) measurement
T h e sites w h ere B M D w asm easu red in clu d ed to tal sk eleto n , lu m b ar sp in e, fem o ral n eck , W ard 's trian g le, g reater tro ch an ter, arm s, leg s, p elv is an d h ead , b y m ean s o f d u al en erg y X -ray ab so rp tio m etry (D E X A ) in D P X -L eq u ip m en t (L u n ar C o rp ., M ad iso n , W I, E U A ). T h e B o n e M in eral C o n ten t (B M C ) m easu rem en t o f th e en tire b o d y w as also u tilized ih o u r stu d y . A ll th e p atien ts w ere ex am in ed th ro u g h
medium scan mode,
at 7 .8 crn ls; th e size o f th e sam p le w as 1 .2 x 1 .2 m m , at 1 /6 4 s in terv als; an d a co llim atio n so u rce o f 1 .6 8 m m . O u r ex p erien ce sh o w s th at th e v ariatio n co efficien t o f th ese m easu rem en ts w as lo w er th an 1 .5 % in all b o n e areas.Body Composition
measurement
T h e h eig h t w as m easu red b y a stad io m eter an d th e b o d y w eig h t (B W ) b y a F ilizo la electro n ic b alan ce. M ass m easu rem en t o f so ft b o d y sectio n s, ie lean an d fatty tissu es, w as also o b tain ed th ro u g h D E X A . R esu lts v ery sim ilar to
th o se o b tain ed th ro u g h th is m eth o d , u sin g w eig h t scales an d an th ro p o m etric m easu rem en ts o f cu tan eo u s fo ld s, sh o w th at it is a reliab le m eth o d fo r d eterm in in g b o d y co m p o sitio n 2 4 . T h is tech n iq u e u tilizes an x -ray so u rce at tw o lev eIs o f en erg y . T h e atten u atio n o f th ese en erg ies b y th e lean , fatty o r b o n e tis su es is d ifferen t, w h ich allo w s th e m ass calcu latio n fo r each sectio n . T h e v ariatio n co efficien t o f fat (F M ) an d lean (L M ) m ass m easu rem en ts w as lo w er th an 3 % .
Body composition
influence
on
BMO
W e ex am in ed th e in flu en ce fro m th e ab so lu te v alu es o f L M , F M , B W an d h eig h t, as w ell as ag e an d y ears 'sin ce m en o p au se (Y S M ), o n B M D o f d ifferen t b o n e areas, an d o n B M C o f th e en tire b o d y . In o rd er to m in im ize b o d y size d ifferen ces an d id en tify th e p ro p o rtio n o f lean an d fatty tissu es an d co n seq u en tly its in flu en ce o n B M D , w e calcu lated fat m ass (F M I) an d lean m ass (L M I) in d ex es, d iv id in g th e F M an d L M ab so lu te v alu es (k g ) b y th e sq u are o f each p atien t's h eig h t (h ); resp ectiv ely F M /h 2 an d L M /h 2 . A n o th er p aram eter u tilized w as th e b o d y m ass in d ex , B M I (B W /h 2 ). T h e d ata w ere an aly zed th ro u g h lin ear reg ressio n : th e ab so lu te v alu es an d th e resp ectiv e an th ro p o m etric p aram eters in d ex es w ere p lo tted ag ain st th e B M D o f all b o n e areas. T h e slo p es w ere co m p ared fo r each site, to d etect w h ich p aram eter h as g reater in flu en ce o n B M D .
C o n sid erin g th at th e B M D is calcu la~ ed b y d iv id in g th e b o n e m in eral co n ten t (g ) b y sk eleto n area (cm 2 ), w e o b serv e th at th is m easu rem en t d o es n o t reflect a real d en sity , sin ce
it
d ep en d s o n th e b o d y size, an d fo r th at reaso n th e taller in d iv id u aIs p resen t o v erestim ated b o n e d en sity 2 5 . S o m e research ers h av e su g g ested th at th e d iv isio n o fB M D b y th e p atien t h eig h t is th e b est an d m o st co n v en ien t ex p ressio n fo r th e real b o n e d en sity 2 1 . F o r th ese reaso n s, th e all-areas B M D /h w as also u tilized .Analysis of body composition
influence
on
bone mass
decrease in relation to years since menopause
F o r th e ab so lu te v alu es o f F M , L M e B W an d fo r each an th ro p o m etric in d ex (B M I, L M I, an d F M I), th e to tal g ro u p o f w o m en w as d iv id ed , u tilizin g th e m ed ian o f each p aram eter, in to tw o p o p u latio n s: P I e P 2 , resp ectiv ely th e lo w er an d h ig h er ab so lu te v alu es o r in d ices o f F M , L M o r B W . T h e B M D m easu rem en ts o f d ifferen t b o n e areas w ere co rrelated w ith Y S M , an d afterw ard s w e d id lin ear reg ressio n s to estim ate th e sp eed o f b o n e m ass d ecrease (slo p e - g /cm 2 /y ear). F in ally , th e slo p e o f th e P 1 an d P 2 straig h t lin es w ere co m p ared in o rd er to in v estig ate w h eth er th e p o p u latio n s w ith lo w er o r h ig h er an th ro p o m etric
M A R O N E , M . M . S . ; G O U V E I A , C . H . A . ; L E W I N , 5 . ; M A L V E S T I T I , L . F . ; B I A N C O , A . C . -I n f lu e n c e o f b o d y c o m p o s it io n o n t h e b o n e m a s s o f p o s t m e n o p a u s a l w o m e n
la b ia 1
C h a ra e te ristie s o f th e p o p u la tio n stu d ie d
p a ra m e te rs d iffe re d re la tin g to th e d e c re a se in b o n e m a ss a sso c ia te d w ith th e m e n o p a u se y e a rs.
la b le 2
B M D V a lu e s a n d Z -se o re o f a re a s stu d ie d
F M - fa tty m a ss, L M - le a n m a ss a n d B M I, F M I a n d L M I
a re re sp e ctive ly b o d y , fa tty a n d le a n m a ss in d ice s
W e u tilize d a cu to ff o f -2 .5 sta n d a rd d e via tio n s b e lo w th e
yo u n g a d u lt a ve ra g e fo r o ste o p o ro sis, a n d sta n d a rd
d e via tio n b e tw e e n -1 a n d -2 .5 fo r o st~ o p e n ia .
In te rva l Z -S co re R a n g e
0 .8 9 -1 .3 3 -2 .2 7 a -3 .4 0 0 .7 4 -1 .4 6 -1 .6 4 a -3 .2 2 0 .5 2 -1 .2 0 -1 .0 6 a -2 .4 4 0 .4 1 -1 .2 1 -1 .1 1 a -3 .3 3 0 .4 9 -1 .0 6 -0 .9 3 a -0 .4 3 0 .8 4 -,1 .3 1
0 .7 3 -1 .0 8 0 .8 6 -1 .3 6 1 .6 9 -2 .6 1
Correlation of body composition
with
BMD
A s T a b le 3 sh o w s, th e re w e re sig n ific a n t c o rre la tio n s b e tw e e n B M D a n d a n th ro p o m e tric p a ra m e te rs in a lm o st a ll a re a s. H o w e v e r, h e ig h t o n ly h a s in flu e n c e o n B M D o f th e sp in e . T h e b o d y in d e x re su lts (B M I, F M I a n d L M I) h a rd ly d iffe re d fro m th e re su lts o f a b so lu te v a lu e s o f F M , T a b le 1 sh o w s th e c h a ra c te ristic s o f th e w o m e n stu d ie d in te rm so f v a ria tio n , a v e ra g e a n d m e d ia n o f a n th ro p o m e tric p a ra m e te rs, a s w e ll a s a g e a n d m e n o p a u sa l y e a rs. B y u tiliz in g a c u to ff o f -2 .5 sta n d a rd d e v ia tio n s b e lo w th e a v e ra g e fo r y o u n g a d u lts fo r o ste o p o ro sis, a n d sta n d a rd d e v ia tio n o f b e tw e e n -1 a n d -2 .5 fo r o ste o p e n ia , 2 6 % o f th o se w o m e n p re se n te d o ste o p o ro sis a n d 7 4 % o ste o p e n ia in th e sp in e , w h ic h c o rre sp o n d s to th e risk fo r fra c tu re in th is a re a a t th is sta g e in th e life o f th e m a jo rity o f p a tie n ts w h o w e re c o n sid e re d in th is stu d y2 6 . B e sid e s th is, a ll th e w o m e n p re se n te d o ste o p e n ia in th e fe m o ra l n e c k . T a b le 2 sh o w s th e p a tie n ts' d e n sito m e tric c h a ra c te ristic s. It is c le a r th a t th e p o p u la tio n a l sa m p le u tiliz e d in th is stu d y h a s b o th n o rm a l a n d o ste o p o ro tic w o m e n , w h ic h is ty p ic a l fo r a p o p u la tio n o f p o stm e n o p a u sa l w o m e n .
R E S U L T S
M e d ia n
5 1
2 .2 5 1 .5 6 6 4 .0 2 5 .8 2 2 .9 9 .1 0 3 7 .5 1 5 .2
~ n te rva l
3 8 -6 2 0 .5 0 -1 0 1 .4 4 -1 .7
4 0 -9 3 1 8 .5 -3 8 .3
7 .0 -4 3 .0 2 .9 -1 9 .7 2 7 .8 -4 9 .7 1 2 .8 -1 8 .9
A ve ra g e :t S .O .
5 0 .1 :t 4 .8 3 .5 :t 3 .0 1 1 .5 6 :t 0 .1 6 4 .2 :t 1 0 .9 2 6 .3 :t 4 .5 2 2 3 .8 :t 7 .7 3 9 .7 6 :t 3 .3 0 3 7 .4 :t 4 .0 7 1 5 .3 :t 1 .4 4
A ve ra g e :tS O
1 .1 2 1 :t0 .0 9 5 1 .0 7 9 :t0 .1 6 2 0 .8 9 7 :t0 .1 4 5 0 .7 6 7 :t0 .1 6 9 0 .7 4 3 :t0 .1 2 6 1 .0 8 7 :t0 .1 1 6 0 .9 1 9 :t0 .0 8 2 1 .1 0 7 :t0 .1 1 0 2 .1 4 0 :t0 .2 2 5
B M O
T o ta l ske le to n
S p in e (L 2 -4 )
F e m u ra l N e ck
W a rd
T ro ch a n te r
P e lvis
A rm s
L e g s
H e a d A g e (ye a rs)
C lim a cte riu m (ye a rs)
H e ig h t (m )
W e ig h t (K g )
B M I
F M (kg )
F M I
L M (kg )
L M I
la b ia 3
C o rre la tio n in d e x (r) b e tw e e n B M D fro m se ve ra l b o n e a re a s a n d a n th ro p o m e trie e o m p o n e n ts
B M O
T o ta l B o d y
L 2 -L 4
F e m u ra l N e ck
P e lvis
A rm s
L e g s
W a rd
T ro ch a n te r
H e a d
T o ta l B M C
F M
0 .3 3d 0 .2 1 0 .2 1 0 .4 5a 0 .2 3 0 .2 2 0 .2 6 ' 0 .1 8 0 .2 7 ' 0 .3 4d
F M I
0 .3 5d 0 .2 3
0 .1 0 0 .5 0 a
0 .2 0 0 .2 1 0 .1 3 0 .1 6 0 ;3 2e
0 .3 9b
L M
0 .4 2a 0 .3 9b 0 .3 8c
0 .4 9a 0 .5 1a 0 .3 7C 0 .3 6a 0 .3 9b 0 .2 5 0 .6 7a
L M I
0 .4 1b 0 .2 2 0 .3 0e
0 .4 8a
0 .4 3a
0 .2 9f 0 .2 9f 0 .3 6c
0 .2 8f 0 .4 6a
W e ig h t
0 .4 9a
0 .4 1 b 0 .3 0c
0 .6 3a
0 .4 1a
0 .3 8b 0 .3 1e
0 .3 2e
0 .3 7C 0 .6 7a
B M I
0 .4 5a
0 .2 8 ' 0 .2 1 0 .5 8a
0 .1 0e
0 .3 0e
0 .2 3 0 .2 7 ' 0 .3 7c
0 .4 9a
H e ig h t
0 .1 1 0 .3 2e
0 .1 8 0 .1 3 0 .2 3 0 .1 9 0 .1 7 0 .1 2 0 .0 1 0 .4 2a
F M - fa tty m a ss, L M - le a n m a ss a n d B M I, F M I a n d L M I a re re sp e ctive ly b o d y, fa tty a n d le a n m a ss in d ice s. T h e
sta tistica l va lu e s o f co rre la tio n s a re in d ica te d :
a p < 0 .0 0 1 b 0 .0 0 1 < p < 0 .0 0 2
C
'
0 .0 0 2 < p < 0 .0 0 S
d 0 .0 0 S < p < 0 .0 1 e0 .0 1 < p < 0 .0 2
f 0 .0 2 < p < 0 .O S
M A R O N E , M .M .S .; G O U V E IA , C .H .A .; L E W IN , S .; M A L V E S T IT I, L .F .; B IA N C O , A .C . -In flu e n ce o f b o d y co m p o sitio n o n th e b o n e m a ss o f p o stm e n o p a u sa l w o m e n
T a b le 4
C o rre la tio n in d e x (r) b e tw e e n B M D /h fro m b o n e a re a s a n d a n th ro p o m e tric c o m p o n e n ts
B M D /h F M F M I L M L M I W e ig h t B M I
T o ta l B o d y 0 .3 8c 0 .4 2a 0 .1 9 0 .4 6a 0 .3 8b 0 .5 1a L 2 -L 4 0 .3 2d 0 .3 0e 0 .2 8f 0 .2 7f 0 .3 7c 0 .3 5a F e m u ra l N e c k 0 .1 5 0 .1 4 0 .2 7f 0 .3 4d 0 .2 4 0 .2 5b P e lv is 0 .5 3a 0 .5 6a 0 .3 1
e 0 .5 3a 0 .5 5a 0 .6 4a A rm s 0 .2 6f 0 .2 8f 0 .3 0e 0 .5 0a 0 .3 2d 0 .4 0a L e g s 0 .2 7f 0 .2 9f 0 .1 8 0 .3 5d 0 .3 0f 0 .3 8a
W a rd 0 .1 7 0 .1 6 0 .2 7f 0 .3 2e 0 .2 7f 0 .2 6a
T ro c h a n te r 0 .1 9 0 .2 1 0 .2 8f 0 .4 0b 0 .2 8f 0 .3 1 a H e a d 0 .3 1e 0 .3 7c 0 .0 6 0 .3 2e 0 .2 8f 0 .4 2a F M - fa tty m a s s , L M - le a n m a s s a n d B M I, F M I a n d L M I a re re s p e c tiv e ly b o d y , fa tty a n d le a n m a s s in d ic e s . T h e s ta tis tic a l v a lu e s o f c o rre la tio n s a re in d ic a te d :
a p < 0 .0 0 1 b 0 .0 0 1 < p < 0 .0 0 2 C0 .0 0 2 < p < 0 .0 0 s
d 0 .0 0 S < p < 0 .0 1
e0 .0 1 < p < 0 .0 2
f 0 .0 2 < p < 0 .O S
L M a n d B W . F M p o s i t i v e l y a n d s i g n i f i c a n t l y i n f l u e n c e d B M D o f t h e e n t i r e b o d y , p e l v i s , W a r d 's t r i a n g l e a , n d h e a d , a n d t h e s t r o n g e s t c o r r e l a t i o n o c c u r r e d f o r t h e p e l v i s . H o w e v e r , w h e n t h a t p a r a m e t e r w a s c o r r e c t e d f o r h e i g h t ( F M I ) , m o s t o f t h e c o r r e l a t i o n s t e n d e d t o b e c o m e w e a k e r . L M p r e s e n t e d s i g n i f i c a n t c o r r e l a t i o n w i t h a l l s i t e s a n a l y z e d , e x c e p t t h e h e a d , c o n s i d e r i n g t h a t t h e g r e a t e s t c o r r e l a t i o n i n d i c e s o c c u r r e d i n t h e a r m s a n d p e l v i s . T h e u t i l i z a t i o n o f t h e l e a n m a s s i n d e x ( L M I ) b a r e l y m o d i f i e d t h e r e s u l t s , e x c e p t i n t h e s p i n e , w h e r e t h e J e a n t i s s u e d i d n o t a f f e c t b o n e m a s s s i g n i f i c a n t I y . T h e B M I a n d B W p r e s e n t e d p o s i t i v e c o r r e l a t i o n w i t h B M D i n a l I a r e a s , a n d f o r t h e s e t w o p a r a m e t e r s t h e c o r r e l a t i o n w a s s t r o n g e r i n t h e p e l v i s . I t i s c l e a r t h a t t h e p e I v i s w a s t h e b o n e a r e a w h i c h p r e s e n t e d t h e g r e a t e s t c o r r e l a t i o n s w i t h a l m o s t a l l p a r a m e t e r s .
T a b l e 4 s h o w s t h a t t h e c o r r e l a t i o n o f B M D w i t h h e i g h t h a r d l y m o d i f i e d t h e r e s u l t s e x h i b i t e d i n T a b l e 3 , a l t h o u g h t h e c o r r e l a t i o n c o e f f i c i e n t s t e n d e d t o i n c r e a s e f o r F M , F M I , L M I , a n d B M I , a n d d e c r e a s e f o r L M a n d B W .
9 7
57
n
P C (K g )
C o l u n a l o m b a r ( L 2 - L 4 )
1 . 7 1 . 5 1 . 3 1 . 1 0 . 9 0 . 7
0 .5
3 7
57
77
97
P C (K g )
C o l o d o F ê m u r
1 . 4
~ . N
a
1 . 2~
'-ti 1
~ 0 . 8 ~ 0 . 6
0 . 4 3 7
1 . 4
1 . 5 1 . 2
1 . 3 1
1 . 1 0 . 8
« = 0 . 0 1 4 0 . 9 « = 0 . 0 1 6
0 . 6
•
R = O .3 8 0 . 7 R = O .3 90 . 4 0 . 5
25
35
4 555
25
3 5 4 5 5 5L (g ) L (g )
4 0 1 . 7
1 . 5 1 . 3
1 .1
0 . 9 0 . 7 0 . 5
1 0 2 0 3 0 4 0
o
1 0 2 0 3 0F (k g ) F (k )
F ig u re 1 - C o rre la tio n o f fe m o ra l B M D a n d s p in e (L 2 -L 4 ) w ith th e w e ig h t (B W ), le a n a n d fa tty m a s s e s . T h e c u rv e s re p re s e n t lin e a r re g re s s io n s fro m th e re s u lts o b ta in e d .
0 . 4 O 1 . 4 1 . 2 1
0 . 8 0 . 6
M A R O N E , M .M .S .; G O U V E IA , C .H .A .; L E W IN , S .; M A L V E S T IT I, L .F .; B IA N C O , A .C . -In flu e n c e o f b o d y c o m p o s itio n o n th e b o n e m a s s o f p o s tm e n o p a u s a l w o m e n
la b ia 5
C o m p a ris o n b e tw e e n le a n (L M ) a n d fa t m a s s e s (F M ) a n d b o d y w e ig h t (B W ) in flu e n c e s o n B M D o f
s k e le ta l a re a s
B M D (a re a s ) L M x F M
P
L M x W e ig h tp
F M x W e ig h tp
T o ta l' B o d y > 0 .0 5 < p < 0 .1 0 > 0 .0 5 < p < 0 .1 0 > > 0 .5 0 L 2 -L 4 > 0 .0 2 < p < 0 .0 5 * > 0 .0 5 < p < 0 .1 0 > > 0 .5 0
F e m u ra l N e c k > 0 .0 2 < p < 0 .0 5 * > 0 .0 2 < p < 0 .0 5 * < > 0 .5 0 P e lv is > 0 .0 5 < p < 0 .1 0 > 0 .0 2 < p < 0 .0 5 * < > 0 .5 0
A rm s > 0 .0 0 2 < p < 0 .0 0 5 * > 0 .0 0 2 < p < 0 .0 0 5 * > > 0 .5 0 L e g s > 0 .0 5 < p < 0 .1 0 > 0 .0 5 < p < 0 .1 0 > > 0 .5 0 W a rd > 0 .1 0 < p < 0 .2 0 > 0 .0 5 < p < 0 .1 0 < > 0 .5 0
T ro c h a n te r > 0 .0 0 2 < p < 0 .0 5 * > 0 .0 2 < p < 0 .0 5 * > > 0 .5 0 H e a d < 0 .2 0 < p < 0 .5 0 < 0 .2 0 < p < 0 .5 0 < > 0 .5 0
T o ta l B M C > < 0 .0 0 1 * > < 0 .0 0 1 * > 0 .2 0 < p < 0 .5 0
T h e re s u lts w e re o b ta in e d fro m s lo p e c o m p a ris o n fo r e a c h c o rre la tio n ; "p " re p re s e n ts s ta tis tic a l v a lu e le v e is .
R e g a r d in g th e in v e s tig a tio n o f th e a n th r o p o m e tr ic c o m p o n e n t w ith g r e a te s t in f lu e n c e o n B M D , T a b le 5 s h o w s th a t th e le a n tis s u e te n d e d to b e th e m o s t im p o r ta n t p a r a m e te r in a ll b o n e a r e a s , e x c e p t in th e h e a d . B W a n d F M d id n o t p r e s e n t d if f e r e n t e f f e c ts to e a c h o th e r . F ig u r e 1 illu s tr a te s th e s e c o r r e la tio n s f o r th e f e m o r a l n e c k a n d s p in e . I t is p o s s ib le to o b s e r v e th a t in b o th th e f e m o r a l n e c k a n d L 2 -L 4 , th e g r e a te s t s lo p e s o c c u r r e d in th e r e la tio n s h ip b e tw e e n L M a n d B M D . T h e c o m p a r is o n b e tw e e n in d ic e s a ls o s h o w e d th a t th e le a n tis s u e ( L M I ) is th e m o s t im p o r ta n t p a r a m e te r . H o w e v e r , w h e n th e s a m e c o m p a r is o n s w e r e m a d e r e la tin g to B M D I h , th e te n d e n c y f o r le a n tis s u e to b e th e m o s t im p o r ta n t c o m p o n e n t r e m a in e d , b u t d id n o t r e a c h th e s ig n if ic a n c e lim it in a n y a r e a o f th e s k e le to n .
Influence of age and years since menopause
o nbone
mineral density
I n a lI b o n e a r e a s w e o b s e r v e d lo w e r B M D a s th e p a tie n ts ' a g e s in c r e a s e d . H o w e v e r , th a t c o r r e la tio n w a s o n ly s ig n if ic a n t in W a r d 's tr ia n g le , w h e r e th e r e w a s a d e c r e a s e o f a b o u t 1 .2% p e r y e a r . I n o th e r a r e a s , b o n e lo s s r a n g e d f r o m 0 .1 to 0 .7 % . O n th e o th e r h a n d , th e r e la tio n s h ip A M to B M D w a s s ig n if ic a n t in a lm o s t a ll b o n e a r e a s , w ith th e e s tim a te d r a te s o f b o n e d e n s ity d e c r e a s e r a n g in g f r o m 0 .6 to 2 .6 % p e r y e a r . A s c a n b e o b s e r v e d in T a b le 6 , th e s p e e d o f b o n e m a s s d e c r e a s e d if f e r e d b e tw e e n th e d is tin c t s ite s a n a ly z e d , w ith th e h e a d , W a r d 's tr ia n g le , s p in e a n d f e m o r a l n e c k b e in g th e a r e a s w h ic h p r e s e n te d g r e a te r d e c r ~ a s e in b o n e m a s s . F ig u r e 2 d e m o n s tr a te s th is c o r r e la tio n f o r th e s p in e , w h e r e th e r e w a s a B M D d e c r e a s e o f a p p r o x im a te ly 1 4 .4 m g /c m2 p e r y e a r .
Influence of body composition
o nbone mass decrease in
relation to years since menopause
T a b le 7 s h o w s th a t w o m e n w ith lo w e r F M , L M a n d B W p r e s e n te d g r e a te r d e c r e a s e in B M D in a lm o s t a ll a r e a s , w h e n c o m p a r e d w ith th o s e th a t p r e s e n te d h ig h e r v a lu e s o f th e s e p a r a m e te r s . T h e u tiliz a tio n o f b o d y c o m p o s itio n in d ic e s ( B M I , F M I a n d L M I ) le d to v e r y s im ila r r e s u lts . R e g a r d in g B M C o f th e e n tir e s k e le to n , w e d id n o t f in d s ig n if ic a n t d if f e r e n c e s b e tw e e n th e p o p u la tio n s w ith h ig h e r o r lo w e r q u a n tity o f e a c h a n th r o p o m e tr ic p a r a m e te r ( B W , F M a n d L M ) .
D IS C U S S IO N
T h e r e s u lts in d ic a te th e p o s itiv e in f lu e n c e o f B W o n B M D o f p o s tm e n o p a u s a l w o m e n , a s w e ll a s its m a in c o m p o n e n ts , le a n a n d f a tty m a s s . T h is in f lu e n c e c o n tin u e d e v e n w h e n w e tr ie d to m in im iz e th e s c a le e f f e c ts th r o u g h th e a n th r o p o m e tr ic in d ic e s ( B M I , F M I , a n d L M I ) a n d B M D / h . F u r th e r m o r e , w e f o u n d th e le a n m a s s to b e th e m o s t im p o r ta n t d e te r m in a n t o f b o n e m in e r a l d e n s ity , w h ic h m e a n s th a t s lim m e r p o s tm e n o p a u s a l w o m e n , a n d e s p e c ia lly th e le s s m u s c u la r o n e s , a r e a t g r e a te r r is k o f d e v e lo p in g o s te o p o r o s is . O n th e o th e r h a n d , w e o b s e r v e d th a t th e h ig h e r th e v a lu e s o f B W a n d its c o m p o n e n ts ( F M a n d L M ) a r e , th e lo w e r th e e s tim a te d r a te o f b o n e lo s s a s s o c ia te d w ith th e m e n o p a u s e . I n s p ite o f p o o r k n o w le d g e o f m e c h a n is m s in v o lv e d in th e r e la tio n o f b o d y c o m p o s itio n to B M D d u r in g th e c lim a c te r ic p e r io d , w e h a v e p u t f o r w a r d s o m e h y p o th e s e s .
M A R O N E , M .M .S .; G O U V E IA , C .H .A .; L E W IN , S .; M A L V E S T IT I, L .F .; B IA N C O , A .C . -In flu e n c e o f b o d y c o m p o s itio n o n th e b o n e m a s s o f p o s tm e n o p a u s a l w o m e n
Slope indicates the estimated speed of bone mass loss.
Table 6
C orrelation betw een B M O and m enopausal years
Referring
to the Iean mass, it is understood
that the
mechanicaI stress generated by muscular contraction, which
results in stimulus for bone formation,
is the way that this
lean mass can positively
interfere in the bone mass. This is
evident
in
the
case
of
individuaIs
subjected
to
immobilization,
for whom there is a large and fast decrease
in bone mass27. M oreover,
men present higher BM D than
women,
and this is partly
due to men presenting
higher
muscular
mass. In evidence
for this is the fact that the
difference
in bone density
between
the sexes disappears
when
BM D
is corrected
for the muscular
mass28,29. In
addition,
the bone loss associated
with ageing is partially
related to the muscular
mass decrease,
since the correction
of BM D for the lean mass also annuls the bone loss related
to age
30•
. Regarding
the fatty
mass,
one
quite
acceptable
explanation
is the greater mechanical
stress resulting
from
the increased muscular activity for the action of supporting
and/or
locomotion
of more
corpulent
women,
which
stimulates
bone formation
as already mentioned.
The high
production
of estrone
by the adipocytes
from
adrenal
androgens in more obese women was suggested a long time
ago as a factor protecting
against mass loss associated
with
the menopause.
However, recent studies have showed that
the relation estrone to BM D is much less than that of fat to
BM D22. Furthermore,
the fact that there is equal influence
of fatty mass in premenopausal
women
suggests
that it is
not
the
principal
mechanism
responsible
for
this
correlation21,22, especially
because
these
women
hardIy
depend
at all on estrogen
produced
by the adipocytes.
Another endocrine
mechanism
that has been suggested
to
explain the FM effect is the hyperinsuIinemia
which comes
from obesi ty, in view of the fact that insulin has an anaboIic
effect on bone tissue. However, in spite of finding positive
correlations
between
bone density and circuIating
insulin
leveIs in postmenopausal
women, we did not find convincing
10
8
6
4
2
o
1.7
.•...
1.5
u
1.3
....•.•.
1.1
c
0.9
0.7
0.5
Figure 2 -C orrelation of spine B M D (L2-L4) w ith the c1im acteric period. There w as abone m ass decrease of approxim ately 14.4 m g/ cm2/year (slope). The correlation coefficient w as 0.27 (0.02<p<0.05).
A reas S lope
R
p(m g/cm2/year)
Total B ody -9.2 0.31 0.01 <p<0.02* S pine (L2-4) -14.4 0.33 0.02<p<0.05* Fem ural N eck -11.4 0.24 0.05<p<0.10 W ard -20.0 0.35 0.002<p<0.005* Trochanter -7.10 0.17 0.10<p<0.20 P elvis -8.10 0.21 0.10<p<0.20* A rm s -6.0 0.23 0.05<p<0.10 Legs -9.97 0.27 0.02<p<0.05* H ead -23.1 0.31 0.01 <p<0.02*
p
<0.001 * <0.001 * 0.02<p<0.05* 0.01 <p<0.02* >0.50 <0.001 * <0.001 * 0.10<p<0.20 >0.50 >0.50 W eightP 1>P 2 P 1>P 2 P 1>P 2 P 1>P 2 P 1>P 2 P 1>P 2 P 1>P 2 P 1>P 2 P 1<P 2 P 1>P 2
p
<0.001 * <0.001 * 0.002<p<0.005* 0.002<p<0.005* >0.50 <0.001 * <0.001 * <0.001 * 0.002<p<0.005* >0.50p
<0.001 * <0.001 * 0.20<p<0.50 0.05<p<0.10 <0.001 * <0.001 * >0.50 0.05* 0.20<p<0.50* >0.50 FMP 1>P 2 P 1>P 2 P 1<P 2 P 1<P 2 P 1>P 2 P 1>P 2 P 1=P 2 P 1>P 2 P 1>P 2 P 1>P 2
Table 7
C om parison of bone m ass reduction through .the m enopausal years, in populations w ith low er (P 1) or higher (P 2) FM , LM or B W
LM
P 1>P 2 P 1>P 2 P 1>P 2 P 1>P 2 P 1>P 2 P 1>P 2 P 1>P 2 P 1>P 2 P 1>P 2 P 1>P 2 B M O areas
Total B ody L2-L4
Fem ural N eck W ard
Trochanter P elvis A rm s Legs H ead Total B M C
The results w ere obtained from slope com parison of P 1 vs. P 2 for each bone area.
M A R O N E , M .M .S .; G O U V E IA , C .H .A .; LE W IN , S .; M A LV E S TITI, L.F.; B IA N C O , A .C . -Influence of body com position on the bone m ass of postm enopausal w om en
Table 8
Correlations between body composition
measurements
H e ig h t W e ig h t B M I F a t F M I L e a n
W e ig h t 0 .2 4b
B M I -0 .1 8 0 .8 3a
F a t 0 .0 5 0 .9 3a 0 .8 4a
F M I 0 .1 7 0 .8 6a
0 .9 4a 0 .9 7a
L e a n 0 .4 9a O '.7 8a 0 .5 8a 0 .5 1a 0 .4 0a
L M I -0 .1 6 0 .7 1a
0 .7 9a
0 .5 4a 0 .5 7a
0 .7 8a
T h e d a ta a re c o rre la tio n c o e ffic ie n ts . T h e s ig n ific a n t c o rre la tio n s a re in d ic a te d .
a p < O .0 0 1 b O .0 2 < p < O .0 5
e v id e n c e to e s ta b lis h h y p e r in s u lin e m ia a s th e m e c h a n is m r e s p o n s ib le f o r th e r e la tio n f a t to B M D 3 1 . M o r e o v e r , th e r e is s o m e g e n e tic e v id e n c e f o r th e r e la tio n F M to B M D , in w h ic h th e r e w o u ld b e c r o s s e d h e r e d i ty o f th e s e a ttr ib u te s 3 2 ,3 3 .
A ll th e s a m e , th e r e s u lts f o u n d in th e c u r r e n t s tu d y d e m o n s tr a te th a t th e m e c h a n ic a l s tr e s s w h ic h c o m e s f r o m m u s c u la r c o n tr a c tio n is th e m o s t im p o r ta n t d e te r m in a n t o f b o n e d e n s ity . E v id e n c e o f th is c a r n e f r o m th e h ig h c o r r e la tio n o f B M D o f th e a r m s w ith L M , a n d th e a b s e n c e o f c o r r e la tio n w ith F M . C o n s id e r in g th a t th is a r e a d o e s n o t c a r r y m u c h w e ig h t, a n d it is a lm o s t c o n tin u a lly m o v in g , th a t is to s a y , u n d e r p e r m a n e n t in f lu e n c e f r o m m u s c u la r a c tiv ity , w e th in k th a t th e m e c h a n ic a l s tr e s s f o s te r e d b y m u s c u la r c o n tr a c tio n is th e d e te r m in a n t f a c to r f o r B M D o f th is a r e a , e s p e c ia lly b e c a u s e th e m o s t o b e s e w o m e n p r e s e n te d th e s a m e r a te o f b o n e m a s s lo s s in th e a r m s , w h e n c o m p a r e d w i th th e s lim m e s t o n e s .
O n th e o th e r h a n d , th e h e a d w a s in f lu e n c e d b y th e f a t, b u t it w a s n o t s ig n if ic a n tly in f lu e n c e d b y L M , a s w o u ld b e p r e d ic te d , c o n s id e r in g th a t th is a r e a h a s lo w m u s c u la r a c tiv ity a n d o b v io u s ly d o e s n o t s u f f e r w e ig h t lo s s . H o w e v e r , a n o th e r in te r e s tin g r e s u lt w a s th a t th e h ig h e s t r a te o f b o n e lo s s , c a u s e d b y th e e s tr o g e n d e f ic ie n c y ( m e n o p a u s e ) , o c c u r s
in th e h e a d ( - 2 3 .1 m g /c m2
/y e a r ) . T h is s u g g e s ts th a t th e la c k o f p r o te c tiv e e f f e c t f r o m m e c h a n ic a l s tr e s s in th is s ite c o u ld p a r tia lly e x p la in th e m o r e a c c e n tu a te d lo s s in th e h e a d , a n d o n c e a g a in p r o v id e s e v id e n c e f o r th e im p o r ta n c e o f , th e m u s c u la r c o m p o n e n t o n b o n e tis s u e .
A n o th e r d e ta il th a t s h o w s th e le a n tis s u e a s th e m a in d e te r m in a n t o f b o n e m a s s w a s th e p o s itiv e a n d s ig n if ic a n t c o r r e la tio n b e tw e e n B M D a n d L M in a r e a s th a t s u p p o r t w e ig h t, a n d w h ic h a r e a f f e c te d b y m u s c u la r a c tiv ity , s u c h a s th e f e m o r a l n e c k a n d le g s ; a n d th e a b s e n c e o f c o r r e la tio n o f B M D f r o m th e s e a r e a s w ith f a t m a s s . I n a d d itio n , w o m e n w ith m o r e le a n m a s s p r e s e n te d le s s b o n e m a s s lo s s in th e s e a r e a s , w h ils t g r e a te r f a t m a s s d id n o t o f f e r th is p r o te c tiv e e f f e c t in th e f e m o r a l n e c k a g a in s t o s te o p e n ia a s s o c ia te d w ith th e m e n o p a u s e .
W ith r e g a r d to th e a g e e f f e c t a n d m e n o p a u s e y e a r s o n b o n e m a s s lo s s , w e d id n o t f in d s ig n if ic a n t in f lu e n c e o f c h r o n o lo g ic a l a g e d u r in g th e f ir s t te n y e a r s o f m e n o p a u s e . O n th e o th e r h a n d , th e d e c r e a s e o f B M D is s tr o n g ly r e la te d to th e c lim a c te r ic p e r io d , e s p e c ia lly in th e h e a d , s p in e ( L 2 -L 4 ) a n d W a r d 's tr ia n g le . T h e s e r e s u lts s e e m to s h o w , in a c c o r d a n c e w ith o th e r tr a n s v e r s a l s tu d ie s3 4, th a t a g e h a s a n o s te o p e n ic e f f e c t in d e p e n d e n t o f th e m e n o p a u s a l y e a r s . A ll th e s a m e , c o n s id e r in g th a t Y S M p r e s e n ts a p o s itiv e c o r r e la tio n w ith a g e , w e th in k th a t th e d e te r io r a tio n in b o n e m a s s d u r in g th e c lim a c te r iu m is d u e to a g e in g e f f e c ts in , a d d itio n to th e e s tr o g e n d e f ic ie n c y e f f e c ts th a t c o m e f r o m
o v a r ia n d e a th . H Q w e v e r , th e m e n o p a u s a l p e r io d w a s s h o w n to b e th e m o s t im p o r ta n t d e te r m in a n t o f b o n e d e n s ity r e d u c tio n .
I n c o n c lu s io n , b o th th e f a tty a n d le a n m a s s e s p o s itiv e ly a f f e c t B M D , b u t th e la tte r c o m p o n e n t is th e m a in d e te r m in a n t o f b o n e m in e r a l d e n s ity . T h e c lim a c te r ic p e r io d , n o t th e a g e in g , is th e p r e d o m in a n t c a u s a tiv e f a c to r f o r b o n e m a s s lo s s d u r in g th e f ir s t te n y e a r s a f te r th e m e n o p a u s e . H o w e v e r , g r e a te r q u a n titie s o f le a n a n d f a tty m a s s e s h a v e a p r o te c tiv e e f f e c t a g a in s t th is r e d u c tio n o f B M D . T h e s e r e s u lts s h o w th a t s lim m e r w o m e n , e s p e c ia lly th o s e w ith le s s m u s c u la r m a s s , p r e s e n t h ig h e r r is k f o r d e v e lo p in g o s te o p o r o s is d u r in g th e p o s tm e n o p a u s a l p e r io d .
M A R O N E , M .M .S .; G O U V E IA , C .H .A .; L E W IN , S .; M A L V E S T IT I, L .F .; B IA N C O , A .C . -In flu e n c e o f b o d y c o m p o s itio n o n th e b o n e m a s s o f p o s tm e n o p a u s a l w o m e n
Objetivo: Investigar a influência do peso corporal (PC), massa gorda (FM) e massa magra (LM) na densidade mineral óssea (BMD) de várias regiões do esqueleto. Participantes: Sessenta e uma mulheres brancas na pós~menopausa (50.1 :t:4.8 anos). Mensuração: Medida do BMD através da densitorTl~Via duo ..energética. Os resultad2s foram analisados através de regressão linear e os slopes de cada ..9urva foram compar~dq~ ..Resultados: Mostraram qU~~ê correlações PC-, FM- e Lry1-BMDforam positivas, enquanto que as correlações idade- e ..ªngsge c1imatério-BMDforam negativo~. ~M.foi o principal fator que influenciou o BMD em quase todas as regiÕ~s ós?eas~ConcILJ~.ª~:FME?LM apresentam efeitq P?sitivon.c.>BM.D,entretanto, Lty1é o principal determinante da massa óssea." Além
90
mais, rnª.i()r~s valpresd~.LMe F'Mtêmum.~f~itopr()tetor na diminuiç~o do BMD decorrente da menopaus,L P()rtanto, .mulheres nqçli.ITlª!érioçom baixo PC,especialmente, bai~oLM apresentam maior risco de desenvolver osteoporose. . .REFERENCES
1. C onsensus developm ent eonferenee - Profilaxis and . treatm ent of osteoporosis. A m 1 M ed 90: 107 -110, 1991. 2. Stevenson, lC ; M arsh, M S. A n atlas of osteoporosis - The
eneyelopaedia of visual m edieine series. The Parthenon publishing group, U SA , N ew lersey, 1992.
3. R iggs, B L; M elton 111,Ll. The prevention and treatm ent of osteoporosis. N Engl 1 M ed 9:620-627, 1992.
4. Lindsay, R . Prevention of osteoporosis. In: Favus, M .J. -Prim er of the M etabolie B one D iseases and D isorders of M ineral M etabolism . N ew Y ork, R aven Press, 240-244, 1993. 5. W orld H ealth O rganization. A ssessm ent offraeture risk and its applieation to sereening for postm enopausal osteoporosis: teehnieal report series. W H O , G eneva, 1994.
6. G ardnell, P; 10hnell, O ; N ilsson, B E. The proteetive value of bone loss for fragility fraetures in w om en: a longitudinal study over 15 years. C aleif Tisue Itern 49:90-94, 1991. 7. H ui, SL; Slem enda, C W ; 10hnson, C C . A ge and bone m ass
as predietors of fraeture in a prospeetive study. 1 C lin Invest 81: 1804-1809, 1988.
8. R oss, PD ; W asnieh, R D ; V ogel, 1M . D eteetion of prefraeture spinal osteoporosis using bone m ineral absorptiom etry. 1 B one M iner R es 3: 1-11, 1988.
9. O tt, SM . B one density in adoleseents. N Engl 1 M ed 325: 1646-1647, 1991.
10. H ui, SL; Slem enda, C .W ; 10hnson, C C . The eontribution of bone loss to potm enopausal osteoporosis. O steoporosis Intern 1 :30-34, 1990.
11. Stevenson, lC ; Lees, B ; D evenport, M ; C ust, M P; G anger, K F. D eterm inants of bone density in norm al w om en: risk. faetors for future osteoporosis. B r M ed 1 298:924-928, 1989.
12. B rew er, V ; M eyer, B ; K eele, M S; U pton, Sl; H agan, R D . R ole of exereise in preventing involutional bone loss. M ed Sei Sports Exereise 15:445-449, 1983.
13 C ohn, SH ; A besam is, C ; Y m asura, S; A loia, lF; Zansi, I; Ellis, K J. C om parative skeletal m ass and radial bone m ineral eontent in blaek and w hite w om en. M etabolism 26: 171-178,
1977.
14. Poeoek, N A ; Eisrnan, lA ; H opper, lL; Y eates, M G ; Sam brook, PN ; Ebert, S. G enetie determ inants ofbone m ass in adults. 1 C lin Invest 80:706-710, 1987.
15. H arris, S; D allal, G E; D aw son-H ughes, B . Influenee ofbody w eight on rates of ehange in bone density of the spine, hip, and radius in postm enopausal w om en. C aleif Tissue Int. 50:19-23,1992.
16. R igs, B L; W ahner, H W ; M elton 111,Ll; R iehelson, LS; ludd, H L; O fford, K P. R ates of bone loss in the appendieular and axial skeletons of w om en. 1 C lin Invest 77: 1187 -1191, 1986. 17. Trem ollieres, FA ; Pouilles, 1M ; R ibot, C . V ertebral
postm enopausal bone loss is redueed in overw eight w om en - a longitudinal study in 155 early postm enopausal w om en. 1 C lin Endoerinol M etab 77:683-686, 1993.
18. C undy, T; Evans, M ; R obert, H ; W attie, D ; A m es, R ; R eid, I. B one density in w om en using depot m edroxyprogesterone aeetate for eontraeeption. B r M ed 1 303: 13-16, 1991.
19. G am baeeiani, M ; Spinetti, A ; Sim one, L; C appagli, B ; M affei, S; Taponeeo, F; Fioretti, P. The rei ative eontributions of m enopause and ageing to postm enopausal vertebral osteopenia. 1 C lin Endoerinol M etab 77:1148-1151,1993.
20. N ordin; B EC ; N eed, A G ; B rigdes, A ; H orow itz, M . R elative eontributions ofyears sinee m enopause, age, and w eight to vertebral density in postm enopausal w om en. 1 C lin Endoerinol M etab 74:20-23, 1992.
MARONE, M.M.S.; GOUVEIA, C.H.A.; LEWIN, 5.; MALVESTITI, L.F.; BIANCO, A.C. -Influence of body composition on the bone mass of postmenopausal women
2 1 . R e id , IR ; P la n k , L D ; E v a n s, M C . F a t m a ss is a n im p o rta n t d e te rm in a n t o f w h o le b o d y b o n e d e n sity in p re m e n o p a u sa l w o m e n b u t n o t in m e n . J C lin E n d o c rin o l M e ta b 7 5 :4 5 -5 1 , 1 9 9 2 .
2 2 . R e id , IR ; A m e s, R ; E v a n s, M C ; S h a rp e , S ; G a m b le , G ; F ra n c e , JT ; L im , T M T ; C u n d y , T F . D e te rm in a n ts o f to ta l b o d y a n d re g io n a l b o n e m in e ra l d e n sity in n o rm a l p o stm e n o p a u sa l w o m e n - a k e y ro le fo r fa t m a ss. J C lin E n d o c rin o l M e ta b 7 5 :4 5 -5 1 , 1 9 9 2 .
2 3 . B e v ie r, W C ; W isw e ll, R A ; P y k a , G ; K o z a k , K C ; N e w h a ll, K M ; M a rc u s, R . R e la tio n sh ip o fb o d y c o m p o sitio n , m u sc le stre n g th , a n d a e ro b ic c a p a c ity to b o n e m in e ra l d e n sity in o ld e r m e n a n d w o m e n . J B o n e M in e ra l R e s 4 :4 2 1 -3 2 ,1 9 8 9 . 2 4 . O g le , G D ; A lle n , JR ; H u m p h rie s, IR J; L u , P W ; B rio d y ,
JN ; M o rle y , K ; H o w m a n -G ile s, R ; C o w e ll, C T . B o d y -c o m p o sitio n a sse ssm e n t b y d u a l-e n e rg y x -ra y a b so rp tio m e try in su b je c ts a g e d 4 -2 6 y . A m J C lin N u tr 6 1 :7 4 6 -7 5 3 , 1 9 9 5 .
2 5 . A d a m i, S ; K a n is, JA . A sse ssm e n t o f in v o lu tio n a l b o n e lo ss: M e th o d o lo g ic a l a n d c o n c e p tu a l p ro b le m s. J B o n e M in e r R e s 1 0 :5 1 1 -5 1 7 , 1 9 9 5 .
2 6 . K a n is, JA ; M e lto n , J; C h ristia n se n , C ; Jo h n sto n , C C ; K h a lta e v , N . T h e d ia g n o sis o f o ste o p o ro sis. J B o n e M in e r R e s 9 : 1 1 3 7 -1 1 4 1 , 1 9 9 4 .
2 7 . S te w a rd , A F ; A d le r, M ; B y e rs, C .M ; S e g re , G V ; B ro a d u s, A E . C a lc iu m h o m e o sta sis in im m o b iliz a tio n : A n e x a m p le
o fre so rp tiv e h y p e rc a lc iu ria . N E n g I J M e d 3 0 6 : 1 1 3 6 -1 1 4 0 , 1 9 8 2 .
2 8 . B o n jo u r, JP ; T h e in tz , G ; B u c h , B ; S lo sm a n , D ; R iz z o li, R . C ritic a I y e a rs a n d sta g e s o f p u b e rty fo r sp in a l a n d fe m o ra I b o n e m a ss a c c u m u la tio n d u rin g a d o le sc e n c e . J C lin E n d o c rin o l M e ta b 7 3 :5 5 5 -5 6 3 , 1 9 9 1 .
2 9 . B u c h s, B . e t a I. D e n sité m in e ra le o sse u se d e la c o lo n n e lo m b a ire , d u c o l e t d e la d ia p h y se fe m o ra u x d 'u n e c h a n tillo n d e la p o p u la tio n g e n e v o ise . S c h w e iz M e d W o c h e n sc h r
1 2 2 :1 1 2 9 -1 1 3 6 ,1 9 9 2 .
3 0 . D o n a ld so n , L J; C o o k , A ; T h o m p so n , R G . In c id e n c e o f fra c tu re s in a g e o g ra p h ic a lly d e fin e d p o p u la tio n . Jo u rn a I E p id e m io l C o m m u n ity H e a lth 4 4 :2 4 1 -2 4 5 , 1 9 9 0 .
3 1 . R e id , IR ; E v a n s, M ; C o o p e r, G JS ; A m e s, R W ; S ta p le to n , J. C irc u la tin g in su lin le v e Is a re re la te d to b o n e d e n sity in n o rm a l p o stm e n o p a u sa l w o m e n . A m e r P h y sio l S o c ie ty 2 8 :E 6 5 5 -E 6 5 9 , 1 9 9 3 .
3 2 . B o u c h a rd , C ; T re m b la y , A ; D e sp ré s, J; e t a I. T h e re sp o n se to lo n g -te rm o v e rfe e d in g in id e n tic a l tw in s. N E n g l J M e d 3 2 2 : 1 4 7 7 -1 4 8 2 , 1 9 9 0 .
3 3 . S tu n k a rd , A J; H a rris, JR ; P e d e rse n , N L ; M c C le a rn , G E . T h e b o d y m a ss in d e x o f tw in s w h o h a v e b e e n re a re d a p a rt. N E n g l M e d 3 2 2 : 1 4 8 3 -1 4 8 7 , 1 9 9 0 .
3 4 . N ila s, L ; C h ristia n se n , C . B o n e M a ss a n d its re la tio n sh ip to a g e a n d th e m e n o p a u se . J C lin E n d o c rin o l M e ta b 6 5 :6 9 7 -7 0 2 , 1 9 8 7 .
M A R O N E , M . M . S . ; G O U V E I A , C . H . A . ; L E W I N , S . ; M A L V E S T I T I , L . F . ; B I A N C O , A . C . -I n f l u e n c e o f b o d y c o m p o s i t i o n o n t h e b o n e m a s s o f p o s t m e n o p a u s a l w o m e n
