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8/9/2019 Jurnal Body Fat in SPE Risk
1/15
Research ajog.org
OBSTETRICS
Early-pregnancy percent body fat
in relation topreeclampsia risk inobese omenLindsay K. Sween, MD; Andrew D. Althouse, PhD;James M. Roberts, MD
OB!ECTI"E# The p$rpose of this st$dyas to identify differences of early-pregnancy body fat percentage and bodymass inde% &B'I( beteen obese omenthat e%perienced preeclampsia and thoseho did not.
ST)*+ *ESI,# e performed an analysis of the
/renatal E%pos$res and /reeclampsia /re0ention 1
longit$dinal cohort st$dy of preeclampsia
mechanisms in obese and o0ereight omen.
omen completed 2$estionnaires regarding their
health beha0iors3 had hematocrit le0el4 eight and
height4 and aist and hip circ$mferences
meas$red4 and had resistance and reactance
meas$red by bioelectric impedance analysis
machine d$ring the first4 second4 and third
trimesters. Total body ater4 fat mass4 and percent
body fat ere calc$lated ith the $se of pregnancy-
specific form$las. /reeclampsia as assessed ith
the clinical definition and a research definition
&clinical preeclampsia pl$s hyper$ricemia(. 5ogistic
regression models ere constr$cted to analy6e
early-pregnancy B'I and body fat percentage
&meas$red at 78.9 1.8 eeksof gestation( as predictors of preeclampsia o$tcomes.
RES)5TS# Three h$ndred se0enty-
three omen ere incl$ded in the
analysis# 18 omen had
preeclampsia by clinical definition
&:.8;(4 and 7< omen had
preeclampsia by the research
definition &1.:;(. There as no
relationship beteen B'I and
preeclampsia risk in obese omen3
hoe0er4 body fat percentage as
associated signifi-cantly ith
increased risk of both the clinical
definition of preeclampsia and the
research definition. In 91= obese
omen4 a 7; increase in body fat
as associated ith appro%imately
79; increased odds of clinical
preeclampsia and 9ey ords#bioelectricimpedanceanalysis4 body fatpercentage4 bodymass inde%4
obesity4preeclampsia
Cite this article as# Seen 5>4
?ltho$se ?*4 Roberts !'.Early-pregnancy percent
body fat inrelation to
preeclampsiarisk in obese
omen. ?m ! Obstet ,ynecol987@3979#:
8/9/2019 Jurnal Body Fat in SPE Risk
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ealth.
The a$thors report noconflict of interest.
Corresponding a$thor#!ames '. Roberts4 '*.
jrobertsmri.magee.ed$
8889-=1A:FG1D.88 H 987@/$blished by Else0ier Inc.
http#FFd%.doi.orgF78.787DFj.ajog.987
8/9/2019 Jurnal Body Fat in SPE Risk
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a7o.or Obstetrics Research
mellitus, renal disease, other medical complications, or multiple
estations were e(cluded. 6omen were recruited in early
prenancy %rom the outpatient clinics o% Maee"6omens
8ospital in Pittsburh, PA, and had body composi"tion assessed
by bioelectrical impedance in the first, second, and third
trimesters -at appro(imately '9, )9, and +! wee*s o% estation0.
he outpatient clinics ser1e primarily low"income, uninsured,unmarried, blac*, or biracial women; +:+ women had complete
early"prenancy -first trimester0 data and were eliible %or
inclusion in this study.
'eas$rements
6omen completed a uestionnaire reardin their health
beha1iors, repro"ducti1e history, and demoraphic char"
acteristics. Standin heiht and waist and hip circum%erences
were measured twice %or accuracy, and the mean o% the ) 1alues
was used. 6aist circum%erence was measured at the natural waist
with the center o% the na1el as a physical landmar*. 8ip
circum%erence was measured 7ust below the bony promi"nence o% the anterior superior iliac spine. 5arly prenancy M/ was
calculated %rom weiht and heiht measurements at the first 1isit-at '9.+ ).< wee*s o% estation0.
reactancemeasured by a/A machine andthe patientJsheiht, weiht,abdominalcircum%erence,and hemat"ocrit
le1el. 6 durin prenancy wascalculated with theeuation deter"mined by Lu*as*i
et al: -able '0.
6 was thenused to estimatethe weiht o% body%at. 6e deri1ed aneuation %or weiht o% %at massat any estational
ae based on theeuations pro1ided
by 1an Raai7 et al.#
6ater content o% %at %ree mass wascalculated usintwo separateeuations, one %or 9 to '9 wee*s o% estation and one%or '9 to 29 wee*so% estation, thatwere deri1ed %rom=iure ' o% 1an
Raai7 et al.# hese
euations were1alidated aainstdeuterium dilution
spaces: and under"
water weihin.#
8ematocritle1el wasmeasured in bloodsamples that wereobtained by1enipuncture.
/reeclampsiadefinition
6e used )
definitions o% preeclampsia. he
first matches thecurrent American
>ollee o%
?bstetrics and
@ynecoloy
definition when we
bean the study, inwhich a woman
with pre1iously
normal blood
pressure has a
blood pressure
'29 andor
8/9/2019 Jurnal Body Fat in SPE Risk
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random urine sample, a catheteri3ed urine sample with 'þ
protein, or a protein"creatinine ratio M9.+. A 7ury re1iewed the
abstracted medical
records to
determine that
criteria %or
preeclampsia had
been satisfied.
Resistance and reactance were measured
with a Buantum /C ioelec"trical
/mpedance Analy3er -RJL Systems, >linton
ownship, M/0. Measurements were ta*en
with the patient lyin supine with arms at a
+9"deree anle %rom the body and with the
les not touchin so as not to disrupt the
electrical circuit. 5lectrodes were attached
in a tetrapolar arranement, with )electrodes on the dorsal sur%ace o% the riht
%oot and ) electrodes on the dorsal sur%ace
o% the riht hand, ' pro(imally and '
distally. he distal electrodes act as the
ener"atin electrodes that transmit a small,
painless
electrical
current; the
pro(imal
electrodes
recei1e the
electric
current and
measure the1oltae drop
between the
riht hand
and riht
%oot.!
Bodycompositioncalc$lations
/A theoryestimates
total bodywater -60
based ontheresistanceand
T?B5E 7
Bodycompositione2$ation
s"ariable
Total body ater4 5
eight of fat mass4 kg
78 k
98 k
18 k
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Research Obstetrics a7o.or
Statistical methods
aseline data were described with the mean standard de1iation
%or contin"uous 1ariables and percentaes %or cate"oric 1ariables
in the total population and separately by preeclampsia status.
Potential di%%erences between women with normal prenancies or
with pre"eclampsia were e1aluated with the use o% t tests %or
continuous 1ariables -eual 1ariances unless otherwise called %or;uneual 1ariances test used where appropriate0 and c) tests %or cateoric di%%erences -=isher e(act test in cases where e(pected
cell counts were N!0. his study %ocused on early prenancy M/
and body %at percentae as pre"dictors o% preeclampsia outcomes;
there%ore, first"trimester measurements o% M/ and body %at were
used in all primary analyses. ody %at percentae was e(amined
as a %unction o% M/; the Pearson correlation coe% ficient is pre"
sented to assess the linear relationship. Lac*in su% ficient sample
si3e to test appropriately %or interaction between M/ and percent
body %at, we instead assessed the relationship between body %at
and preeclampsia by testin %or di%"%erences in percent body %at
between women with preeclampsia and healthy control sub7ectswithin each o% the 6orld 8ealth ?rani3ation M/ classifications
usin t tests -a test with uneual 1ariance where appropriate0.
Loistic reression models were constructed to analy3e M/ and
body %at percentae as continuous 1ariables and allow ad7ustment
%or a limited selection o% potential con"%ounders. ecause the
Prenatal 5(po"sures and Preeclampsia Pre1ention + study was
desined to compare obese women who did or did not e(perience
preeclampsia, we initially limited our loistic reression models
only to obese women. 6e also per%ormed a secondary analysis
that included all participants because o% the surprisinly hih
rates o% preeclampsia in the lean and o1er"weiht women -by the
clinical defini"tion, :.4
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1alues N .9! were considered statistically preeclampsia ris* by both the researchsinificant. and clinical definition. =or each '$ in"
crease in body %at, the ris* o% clinical
RES)5TS preeclampsia increased ')$ -odds ratioStudy participants were aed )+.: 2.' E?RF, '.')2;
E>/F, '.9'#e'.)290, and the ris* o% years; 4+$ o% them were blac*, and
)9$ o% them were smo*ers -able )0. preeclampsia by the research definition) increased )2$ -?R, '.)+
he a1erae M/ was ++.' :.# *m ;'.9!2e'.2!!0. hese relationships were by study desin, most participants were
o1erweiht -)).9$0 or obese -42.'$0. strenthened slihtly when we ad7usted
@estational diabetes mellitus was the model %or ae, race, and smo*in
more common in women in the both status -able 20. 6e considered models
clinical -4.
which suests that body %at percentae 9.
fi compared with '.)< -/,8ealth ?rani3ation M/ classi cations,
only in the hihest cateory o% obese '.92e'.4'0 %or blac* women. 6e did not
women -M/ M29 *m)0 was the body ha1e a su% ficiently lare sample to
fi %ormally test interaction by race.%at percentae sini cantly hiher in
women who e(perienced preeclampsia 6hen we e(amined these relation"
compared with those women who did ships in all women -includin the lean
not -able +0. and o1erweiht women0, neither M/
6e compared M/ and percent nor body %at percentae was associated
body %at as predictors o% preeclampsia sinificantly with increased ris* o% pre") eclampsia by the clinical definition or
in obese women -M/ +9 *m ;the research definition -able !0, whichable 20. 8iher M/ was associated
sinificantly with hiher ris* %or the suested that the relationship betweenresearch definition o% preeclampsia, but percent body %at and preeclampsianot the clinical definition. he e%%ect was was present only in the obese women.no loner sinificant a%ter ad7ustment hese relationships did not 1ary sinifi"%or ae, race, and smo*in status. /n cantly when we ad7usted %or estational
contrast, there was a sinificant rela" diabetes mellitus, waist circum%erence,tionship between percent body %at and or waisthip ratio.
:
8/9/2019 Jurnal Body Fat in SPE Risk
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! ? - )? R+ 9 8 7 @ ? m er i c an ! o $r n al of O b
s t e t r i c s I , y n e c ol o g y
:
8/9/2019 Jurnal Body Fat in SPE Risk
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O b s t e t r i c s
R e s e ar
c h
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Research Obstetrics a7o.or
I,)RE
The relationship beteen B'I and percentage ofbody fat
opreeclampsia
reeclampsia
:8
A8 RS T 8.DD1
D8
F a t
@8
% B o d
y
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T?B5E 1
*istrib$tion of body fatpercentages
Body mass inde% classification
5ean
O0ereight
Obese class 7
Obese class 9
Obese class 1Seen. /ercent body fat andpreeclampsia risk. ?m ! Obstet ,ynecol987@.
8/9/2019 Jurnal Body Fat in SPE Risk
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:
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a7o.or Obstetrics Research
T?B5E <
Relationships beteen body fat percentage and risk of preeclampsia# obese participants onlyOdds ratio
/redictor O$tcome )nadj$sted =@; confidence inter0al ?dj$steda
=@; confidence inter0al
Body mass inde% Clinical preeclampsia &n O 7=( 7.87A 8.=
=urthermore, this
study was desined
to recruit women
with M/ M+9
*m), and most
studies that ha1e
in1estiated the
relationship
between
preprenancy M/
and preeclampsia
ha1e had small
sample si3es o% women with M/
M+! *m). odnar
et al2 %ound that the
?Rs o%
preeclampsia bean
trendin downward
a%ter M/ +!
*m), althouh
they remained M'.9compared with
M/ )' *m).
Rela"tionship
between M/ and
preeclampsia may
become more ill"
defined at 1ery hihM/s, i1en the
1aryin percent
body %at and body
%at distributions
-e, central,
abdominal,
peripheral, or
1isceral0 betweenobese indi1iduals.
Despite these
possible
e(planations, both
the de1iation %rom
8/9/2019 Jurnal Body Fat in SPE Risk
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the well"established association between increasin M/ and
ele1ated preeclampsia ris* and the un"usually hih incidence o%
preeclampsia amon the lean and o1erweiht women do raise
uestions about the
representa"ti1e
nature o% this
cohort.
T?B5E @
Relationships beteen obesity
metricsand riskofpreeclam
psia# allpatients
/redictor
Body mass inde%
Body fat
Research preeclampsia &n O 7<a ?dj$sted for age4 race4 and smoking stat$s.
Seen. /ercent body fat and preeclampsia risk. ?m! Obstet ,ynecol 987@.
!?)?R+ 987@ ?merican !o$rnal of Obstetrics ,ynecology :
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Research Obstetrics a7o.or
Another challene encountered in this study was the unusually
hih rates o% preeclampsia in the lean and o1erweiht women.
he o1erall rate o% preeclampsia has not chaned dramatically in
our Pittsburh population, which suests that the hih incidence
o% preeclampsia may be an aberrant findin that is related to theintentionally small numbers o% lean and o1erweiht women.
Alterna"ti1ely, the cohort is 4+$ blac* women,%or whom the literature is mi(ed with reards to preeclampsia
ris*.+,'4,':
/n one
study, lean blac* women were more li*ely to e(perience
preeclampsia than lean white women, but the trend re1ersed at
M/ M)! *m).+ hus, the lare number o% blac* women in the
lean cohort may e(plain the hih le1els o% preeclampsia in this
roup. /n our study, when we dichotomi3ed by race, there was no
sinificant relationship between body %at percentae in whiteobese women and preeclampsia ris*, probably because o% a
smaller number o% cases in this subset. /n obese blac* women,
there was a sinificant relationship between increasin body %at
percentae and ris* o% preeclampsia by the research, but not bythe clinical definition. his findin is also probably because o% a
small sample si3e in the research definition subroup and not atrue racial interaction. /t was an un%ortunate limitation o% this
study that the sample o% women who e(peri"enced preeclampsia
was not lare enouh to assess adeuately the impact o% body %at
percentae by race.
here were additional limitations in this study. his cohort had
a small number o% cases -+9 cases by the clinical definition, o% which '2 cases also fit the research definition0, which led to wide
confidence inter1als %or some M/ and
body %at percentae
1alues. =urther, we
did not ad7ust %or
multiple
comparisons in our
reression
modelin, which
allowed the possibility o% a
spurious result
bein interpreted as
positi1e; howe1er,
we belie1ed that
the application o% a
particularly harsh
ad7ustment o% the
sinificance le1el
would ha1e made it
impossible to
detect any e%%ect ina cohort with
relati1ely %ew
cases. 6e ad7usted
the loistic
reression model
%or ae, race, and
smo*in durin
prenancy but
could not account
%or other potential
co1ariates, such as
preprenancy and
prenancy diet and
e(ercise habits.
his study
supports the
relationship o% %at
to preeclampsia.
Subseuent lon"
itudinal,
multicenter trials
with larer case
numbers are
needed to %urther
assess the utility o%
/A"determined
body %at
percentae in the
prediction o% pre"
eclampsia onset. -
REERECES
1. ?merican College
of Obstetricians and
,y- necologists.*iagnosis andmanagement of preeclampsia andeclampsia. ?CO,Committee on
/ractice B$lletins#Obstetrics. ?CO,practice b$lletin no.11. Obstet ,ynecol98893==# 7@=-DA.
2.Roberts !'4
,ammill S./reeclampsia recentinsights.ypertension
988@3lebanoff '?4 ess RB4Roberts !'./repregnancy bodymass inde% and theocc$rrence of se0ere hy-pertensi0e disordersof pregnancy.Epidemi- ology988A37:#91opp
5E4 >ing !C4 ong
4 'ayclin /5. l$id
changes d$ring
pregnancy# $se of
bioimpedance
spectroscopy. ! ?ppl
/hysiol 7==@3A:#781A-
4 Roberts 5'4Bron '?. /lasma$ric acid remains amarker of poor o$tcome in hy-
pertensi0epregnancy# aretrospecti0e cohortst$dy. B!O,9879377=#+4 et
al. )ric acid is as
important as
protein$ria in
identifying fetal risk in
omen ith
gestational hyperten-
sion. ypertension
988@3
8/9/2019 Jurnal Body Fat in SPE Risk
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0ariations on the theme. /lacenta 988=391&s$ppl(#S19-A.
13. B$rton ,!4 oods ?4 !a$nia$% E4 >ingdom !C/.
Rheological and physiological conse2$ences of con0ersion of thematernal spiral arteries for $teroplacental blood flo d$r- ing h$manpregnancy. /lacenta 988=318#