VAI TPO CUA TI LE VONG EO/ CHIEU pAO JRONG KIEM SOAT TiNH TRANG BEO P H ! Cf TRE EM
Nguyin Thi Thu Hciu^, Nguyin Thi My Diep\ Nguyin Thu Dung^, Mai Quang Huynh Mai \ Nguyin Hodng Thanh Uyen\ Nguyen Thi Kim Hodng',
Nguyin Thi Hoai Phirang^, Nguyen Thi Kieu Thu' Muc tieu: Xac dinh mirc dp chinh xac cua d le vong eo/ chieu cao (WTHR)trong tam soat tinh trang beo phi ciia tre d6n kham tai khoa dinh dudng benh vien Nhi dong 2 va budc dau xac dinh chi so nguong ciia ti lc nay, Phuong phap nghien ciru: Cat ngang, mo ta co phan tich. Mau nghien ciiu g6m 204 tre, 102 beo phi va 102 khong beo phi, dugc chia thanh 6 nhom theo tuoi va gidi, moi nhOm 17 tre (<6 tu6i, 6-<10 tu6i, > 10 tu6i, nam/ mi). K6t qua: WTHR it phu thupc vao tuoi va gidi hon so vdi BMI. Chi so WTHR c6 khac biet d nhirng benh nhan beo phi va khong beo phi d tre nam mpi tu6i, nu < 6 tudi, nu 6 - <10 tu6i. Ricng nhom nu > 10 tuoi thi khong co sir khac biet.
Dien tich dudi dudng cong ROC dSu d khoang 0,96- 0,98, co kha nang phan each rat tot giira beo phi va khong beo phi. Ngudng chSn doan cho nam la 0.501 va nir la 0.489, nu dudi 10 tuoi la 0.502, vdi dp nhay > 96 -100% va dp dac hieu khoang 80%.Ket luan: Cd the xem xet viec sir dung d le vong eo/ chieu cao dS xac dinh dnh trang beo phi d tre em nam cac lira tuoi va nii dudi 10 tudi.
Chi s6 nay it phu thupc vao tu6i va gidi han la BMI, nhung chinh xac, don gian, de sir dung. De CO chi so chinh xac hon, cSn tien hanh nhung nghien cim cd cd mau ldn hon va day du cac mirc dp ciia beo phi va thira can.
Til- khoa: ty le vong eo/vong mong, beo phi, tre em
L D A T V A N D E :
Tinh trang thira can va beo phi ngay cang gia tang d tre em Viet nam va gay ra nhiSu van dS vS sire khde( dau khdp, anh hudng tam ly, hdi chirng chuyen hda, benh ly tim mach , dai thao dudng...), lam hao tdn tiSn cua ciia gia dinh va xa hdi. Viec phat hien sdm thira can d tre giup dua ra nhung khuySn cao sdm ve chS dp dinh dudng va luyen tap hgp ly, giup ngan ngiia diSn biSn dSn beo phi thyc sy. Viee danh gia thira can va beo phi d tre em: chii ySu dya tren chi sd BMI, tuy nhien ehi sd nay phu thudc lira tudi, gidi, can danh gia theo dudng cong
bach phan vi (percentile) nSn khd sti dung dai chiing, nhat la cho ngudi khdng chuyen mdn. Trong cac nghiSn ciiu trudc day, ti le vdng eo/ chieu cao (WTHR) dugc chiing minh la cd mdi lien he vdi nguy ca benh tim mach tdt hon ca BMI ddi vdi ca ngudi ldn lan tre Idn [1,2,3,5].
Gan day, mdt sd nai trSn thS gidi bat dau sii dyng ti le vdng eo/ chiSu cao dS tam soat tinh trang thua can beo phi, viee sii dyng tuang ddi dan gian ( it phy thudc tudi), tuy nhien cac nghiSn ciiu chu yeu trSn ngudi Idn va tre d liia tudi hgc dudng [4,5,6]. O Viet nam chua cd nghiSn cim ve chi sd nay. Chung tdi tien hanh nghiSn
' Dieu duang - Khoa Dinh duang - Benh Vien Nhi dong 2 - TP HCM
^ ThS.Bs - Khoa Dinh dirang - Benh Vien Nhi d5ng 2 - TP HCM ' Bs. - Khoa Dinh duong - Benh Vien Nhi d6ng 2 - TP HCM
" BS.CKH - Khoa Dinh duang - Benh Vien Nhi d6ng 2 - TP HCM ' KTV - Khoa Dinh duang - Benh Vien Nhi d6ng 2 - TP HCM
ciru nay nham tim ra moi liSn quan giua ti IS vdng eo/chieu cao vdi tinh trang beo phi d tre em va chi sd BMI, qua dd budc dau xac dinh tri sd ngudng ciia ti IS nay trong ddi tugng tre thira can beo phi den kham Dinh dudng benh vien Nhi dong II.
DS tai dugc tiSn hanh vdi mue tiSu:
1. Khao sat cac dac diSm dich tS hgc ciia ddi tugng nghien cuu va so sanh sy phy thugc cua ti IS vdng eo/ chieu cao vao tudi va gidi.
2.Khao sat sy tuong quan giiia ti IS vdng eo/ chiSu cao vdi tinh trang beo phi (danh gia bang tri sd BMI).
3.Xae djnh kha nang phan each va diSm cat cua chi sd ti IS vdng eo/
chiSu cao.
II. DOI TUONG VA PHUOTVG PHAP NGHIEN CUU:
1. Doi tu-gng: Cac tre den kham tai phong kham dinh dudng BV Nhi ddng 2 tir 2-15 tudi. Thu thap tiSn ciiu trSn benh an.
* TiSu chuan loai trii-:
- Hd so benh an thu thap khong day dii.
- Benh nhan cd benh li bat thudng gay ra biSn doi vS chi sd co thS: Benh tim mach, benh ly gan than, phii, cd chudng, benh chuySn chuySn hda, suy dinh dudng thS tap cdi nang (CC/T<-3SD), biSn dang xuong.
2. Phuong phap nghien ciiu: Cat ngang , md ta cd phan tich
- Cong thdc tinh cir mdu. Theo cdng thu-c [2]
N = [(Za+ Zp):Cp + 3 Trong do
N = cd mau nghiSn ciru
Za: chgn a (2 tailed) = 0.05 ^ Za = 1,96 Zp: chgn p (2 tailed) = 0,10 (do manh ciia nghiSn ciru la 90%) ^ Zp = 1,282 C = 0 , 5 x l n [ ( I + r ) ; ( I - r ) ]
Theo nghiSn ciru ciia DS Freednian (I), AJCN 2007, 86:33-40 chi sd R(square) = 0,78
TiiihraN=--17
Doi tugng nghien cu-u dugc chia theo tudi (2-<6 tuoi, 6-<10 tudi, > 10 tudi) va gidi (nam, nu), cd nhdm chung la tre khdng beo phi.
Sd mau can : 17 x 3 nhdm tudi x 2 gidi
= 102 tre beo phi va 102 fre khdng beo phi.
* Phuang phap chgn mau: lay mau lien tiSp cho den khi dii cd mau da tinh toan cho mdi nhdm tuoi va gidi, beo phi hoac khdng beo phi.
Danh gia tinh trang beo phi dya vao chi sd BMI: beo phi nSu BMI > 95 percentile theo tudi va gidi. [8]
Vdng eo dugc do d phan nhd nhat ciia byng hoac ngang rdn nSu khong xac dinh dugc vdng nhd nhat ciia bung. ChiSu cao dugc do tu gdt chan dSn dinh dau khi tre dimg thang.
Xii- ly sd lieu bang phan mSm SPSS 10.0 for Window.
III. KET QUA VA BAN LUAN:
1. Dac diem dich te hgc va so sanh su- phu thuoc cua ti le vong eo / chieu cao vao tuoi va gioi.
- Trong 2 nam 2007-2009, cd 266 benh nhan duge khao sat, trong dd 151 benh nhan beo phi va 115 benh nhan khdng beo phi. Sau khi loai eac trudng hgp khdng dil sd lieu va lay miiu liSn tiep cho dii sd benh nhan ciia mdi nhdm, ed 204 benh nhan dugc nhan vao nghiSn ciru.
- Trong 204 mau nghiSn ciru, cd 102 m^u beo phi va 102 mau khdng beo phi. Sy phan bd theo nhdm tudi trong cac nhdm nhu sau:
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nam tuoi
1=beo phi, 2=du can, 3=bt, 4=sdd
Std Dev = n 4t M s a n = 7 6 N - 2(W 00
Hinh 1: Phan bo theo nhom tuoi
Sy phan bd nay phii hgp md hinh benh nhan beo phi den kham tai benh vien Nhl ddng 2, cao nhat d lira tudi 5-12 tuoi, trudc va sau do cd ti IS thap ban. Sy phan bd tudi nay gan tuang ty d ca 2 nhdm beo phi va khdng beo phi. Cac phan bd nay dugc tam chap nhan nhu phan bd chuan.
nam tuoi
Hinh 2: Phan bo tuoi a nhom beo phi nam tuoi
6 0 8 0 10.0 t_
Hinh 3: Phan b6 tuoi ff nhom khong beo phi
1=beo phi, 2=du can, 3=bt, 4=sdd
Hinh 4: Phan bo cua cac nhom nghien ciJ-u
Bdng I: Sy tuong quan giii-a ti le vong eo/ chieu cao (WTHR) vol gidi tinh
Chiso t Ket luan
BMIva 15,916 0,000 BMI phu thuoc giai WTHR 0,186 0,853 nhi§u vao giai
va giai WTHR it phu thuoc vao gioi tinh han
Bang 1 cho thay Sy tuang quan giira ti le vdng eo/ chiSu cao (WTHR) vdi gidi tinh:
So sanh bang phep kiSm independent T test, khac biet eiia chi sd WTHR d cae nhdm nam va nii khdng cd y nghia thdng ke
Bang 2: Sy tuoTig quan gi&a BMI va ti le vong eo/ chieu cao (WTHR) voi tuoi
Chiso t Ket luan
BMIva 1,9 0,032<0,05 BMI phu thuoc giai 0,804 0,656>0,05 nhiiu vao tu6i WTHR va WTHR it phu giai thuoc vao tuoi
han
Bang 2 cho thay: Sy tuang quan giira BMI va ti le vdng eo/ chieu cao (WTHR) vdi tudi: So sanh bang phep kiem 1 way ANOVA, khac biet ciia chi sd WTHR d cac nhdm tudi khdng cd y nghTa thdng kS.
2. Sy tuoTig quan giiia ti le vong eo/
chieu cao vdi tinh trang beo phi (danh gia bang tri so BMI):
Bang 3 : Tuong quan giua ti le vong eo/ chi6u cao voi tinh trang beo phi
Nhom tuoi sig WTHR khac biet 6 nhom
beo phi va khong beo phi (*) Nam < 6 tuoi
Nam 6-<10 tuoi N a m > 10 tuoi Nu < 6 tuoi Nu:6-<10tu6i Nu-> 10 tu6i
1,124 1,592 0,041 6,631 0,284 4,487
0,297 0,216 0,841 0,015 0,598 0,042
6,730 6,200 13,377
9,223 11,636 -0,940
0,000 0,000 0,000 0,000 0,000 0,361
Co su khac biet Co sir khac biet Co su khac bict Co sir khac biet Co sir khac biet Khong CO sir khac biet (*) 5*0 sdnh bdng phep kiem Independent T test.
Bang 3 cho thay chi sd WTHR d nhiing benh nhan beo phi va khdng beo phi cd khae biet d nhdm nam mgi tudi, nii < 6 tudi, nir 6-<10 tudi . Cdn nhdm nii > 10 tudi thi chua thay sy khac biet giiia tre beo phi va khdng beo phi.
Cac nghiSn ciiu khac cho thay ti IS WTHR cd sy khac biet giua nhdm tre beo phi hoac khdng beo phi ndi chung nhung chii ySu trSn ngudi ldn va tre em liia tudi hgc dudng (8-18 tudi)[6,7]. Chua cd nghiSn cim dS cap dSn lua tudi nhd va lai trong nghiSn ciiu ciing khdng chia ra cac nhdm tudi gidng nhu trong nghien ciru cua chung tdi. KSt qua nghiSn cim ciia chiing tdi thi ti le vdng eo/ chiSu cao cua nhdm tre nii trSn 10 tudi la khdng cd sy khac biet d tre beo phi va khdng beo phi danh gia theo BMI. Cd thS vdi nhdm nii, day la liia tudi da budc vao giai doan tiSn day thi va day thi, do dd sy phat triSn cd nhiSu thay ddi so vdi nhung nhdm tudi khac va chiu sy anh hudng ciia hormone, do vay sy tich liiy md d viing eo cd nhiSu bien ddi. Ngay trong khuySn cao sir dung BMI dS danh gia beo phi d tre > 10 tudi, WHO ciing dua ra y kiSn BMI chi mang tinh tham khao [8]. KSt qua nay cho phep
sir dyng ti IS WTHR dS phat hien tinh trang beo phi d tre nam va tre nii- < 10 tudi. Cdn d tre nir > 10 tudi can cd thSm nhii:ng nghiSn cuu sau ban. Tuy nhiSn, trong cac nghien ctiu vS nguy co benli tim mach, ti sd nay dugc coi la cd mdi liSn he chat ehe vdi tinh trang tang md ndi tang d tre 9-13 tudi, tham chi cdn cd tuong quan manh ban chi sd BMI [3], cd tuang quan manh vdi md mau va nguy ca tim mach ban BMI d tre My 5-17 tudi [1], ngudi Dai Loan trudng thanh [4]. Beo phi ehinh la tinh trang tang md trong ca thS gay ra nhung biSn chung vS sire khoe, chu ySu la md ngi tang. Do dd, cd thS khong ed sir khac biet vS WTHR d nhdm tre beo phi va khdng beo phi danh gia theo BMI, nhung WTHR van cd gia tri trong tiSn lugng nguy ea benh tim mach va tinh trang tang md trong ca thS. DS cd kSt luan chinh xac d ngudi Viet nam, can tiSn hanh them cac nghiSn ciiu vdi cd mau Idn ban.
3. Xac djnh kha nang phan each ciia chi s6 ti le vdng eo/ chieu cao ( dya vao danh gia dien tich duoi dudng cong ROC):
ROC Curve
Nhom nam AUC= 0,955
Nhom tre
Nhom nu' AUC= 0,967
[Shorn n i r <
A U C = 0 , 10 tuoi ,988
Bang 4: Xac dmh kha nang phan each cua chi so ti le vong eo/ chieu cao Dien tich duoi duffng
cong ROC (AUC)
SD Khoang tin cay
95%
Ket luan
Nam Nir
Nu-<10 tu6i
0,965 0,967 0,988
0,019 0,021 0,009
0,000 0,000 0,000
0,927-1,002 0,927-1,007 0,971-1,005
Rat tot Rat t6t Rat t6t
Theo dien tich dual duo-ng cong, neu dat 0,9-1 la rat tot, tir 0,8-0,9 la kha, 0,7-0,8 la trung binh. Nhu vay a ca 3 nhom tuoi, duong cong ROC deu co kha nang phan each rat tot giua beo phi va khong beo phi.
4. Xac djnh diem cat ciia chi so ti le vong eo/ chieu cao (theo gioi), qua do dua ra tri so ngu&ng cua tii le nay trong tien doan tinh trang beo phi a tre.
Chi so
Bang 5 WTHR
Xacd nhd iem cat ciia chi so Do nhay (%)
tile vong eo/ chieu Do dac hieu
cao (%)
theo gioi va tuoi
* Nhom nam 0,4686 0,4821 0,4921 0,5015 0,5279
100 98 98 96,1 92,2
72,5 74,5 78,4 80,4 95,1
De nghi chon Nhom nu chung
0,4788 0,4830 0,4899 0,4950 0,5029 0,5186
99 99 100 100 100 96,1
70,6 74,5 80,4 82,4 84,3 86,3
De nghi chon
* Nhom nu < 10 tuoi 0,4893
0,4899 0,4950 0,5029 0,5118 0,5279 0,5298 0,5322
100 100 100 100 100 94,1 94,1 94,1
70,6 73,5 76,5 79,4 82,4 88,2 91,2 94,1
De nghi chon
DS chan doan sdm tinh trang beo phi d tre, can chgn chi sd cd do nhay cao va do dac hieu kha. Nhu vay, chiing tdi dS nghi chgn ngudng chan doan cho nam la 0,501 va nii la 0,489, neu xet nhdm nir dudi 10 tudi la 0,502, dam bao do nhay >
96 -100% va do dac hieu khoang 80%. So sanh vdi nghiSn cim tai Trung qudc, vdi tri sd ngudng dS nghj la 0,485 vdi nam va 0,475 vdi niJ-, ti sd ciia chiing tdi cao ban mdt chiit. DiSu nay cd thS giai thich la do benh nhan beo phi den kham vdi chiing tdi da sd khi da beo phi nhiSu, ddng thdi nhdm tudi ciia chung tdi cting nhd ban, khi eo cua tre cdn to. Trong cdng ddng, nSu cd mau Idn va dai dien dii cac do beo phi, dti cac nhdm tudi, cd thS se xae dinh dugc ti sd chinh xac hon. Ngoai ra trong nghiSn cim tai Trung qudc, nhdm tre ngudi Han va ngudi Uygur cung cd m u c do beo phi va ti IS md khac nhau [7], diSu do chiing td chiing tdc khac nhau se cd nhirng dac diSm khac trong phan bd md.
Do chua cd mdt nghien ciru nao d tre em Viet nam vS ti IS vdng eo/ chiSu cao nSn chiing tdi chua du co sd de so sanh.
IV. K E T LUAN
1. Chi sd ti IS vdng eo/ chiSu cao it phy thudc vao tudi va gidi, cd kha nang phan each rat tdt giiia beo phi va khdng beo phi d tre em nam mgi tudi va nii dudi 10 tudi.
2. Ngudng duge dS nghj cho tre nam la 0,501 va nii la 0,489, nii dudi 10 tuoi la 0,502.
V. KIEN NGHI:
So vdi BMI, da sd mgi ngudi cd thS de dang diing chi sd nay dS tam soat sdm tinh trang beo phi d tre em. De cd chi sd chinh xac ban, can tien hanh nhiing nghien ciiu cd cd mau ldn h a n va day dii cac muc do eua beo phi va thira can.
TAX LIEU THAM KHAO
1. David S. Freedman, Henry S. Kahn, et al,
2007. Relation of body mass Index and waist-to-height ratio to cardiovascular disease risk factors in children and ado- lescents: the Bogaliisa Heart Study. Am J Clin Nutr. 2007 July; 86(1): 33-40 2. Nguyen Do Nguyen (2006), Phuong phap
nghien cim khoa hoac trong y khoa - Bo mon dich tc - DHY dugc HCM; 34-43 3. Mitsuhiko Hara, Emiko Saitou, Fujihiko
Iwata, Tomoo Okada, and Kensuke Harada (2002). Waist-to-heighl ratio is the best predictor of cardiovascular disease risk factors In Japanese schoolchildren. J Atherosclcr Thromb. 9(3): 127-132.
4. K-C Huang, W-Y Lin, L-T Lee, C-Y Chen, H Lol, H-H Hsia, I-L Liu, W-Y Shau and R-S Lin(2002). Four anthropo- metric indices and cardiovascular risk factors in Taiwan" , International Journal
of Obesity, 26, 1060-1068.
5. Masam Sakurai, Katsuyuki Miura, Toshi- nari Takamura, Tsuguhito Ota,Masao Ishizaki, Yuko IVIorikawa, Temhiko Kido,Yuchi Namse, And Hideaki Naka- gawa (2006). Gender Differences in the Association between Anthropometric In- dices of Obesity and Blood Pressure in Japanese. Hypertens Res Vol. 29, No. 2 6. SD Hsieh, H Yoshinaga and T IVIuto
(2003). Waist-to-height ratio, a simple and practical Index for assessing central fat distribution and metabolic risk in Japanese men and women. International journal of obesity. Vol 27, No 5, pp 610-
6 1 6 .
7. Weill Yan, He Bingxian, Yao Hua, et al (2007), Waist-to-Height Ratio is an Ac- curate and Easier Index for Evaluating Obesity in Children and Adolescents.
Obesity 15:748-752 .
8. WHO standard growth charts 2007.
9. Lc Dinh Van. Phan dch dudng bidu dien R.O.C trong nghien cim y hpc. 2008.
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