Body
Mass
Index Criteria of Central Obesity for Male Japanese
Tohoku J. Exp. Med.,New
2006,
83-86
208,
83
New Body Mass Index Criteria of Central Obesity for
Male Japanese
NAOKO HORIE,1 HIDEAKI KOMIYA,1,2 YUTAKA MORI3 and NAOKO TAJIMA4
1
Department of Exercise Physiology, Utsunomiya University, Utsunomiya,
Japan,
2
Department of Public Health, Dokkyo University, School of Medicine, Tochigi,
Japan,
3
Department of Internal Medicine, National Hospital Organization Utsunomiya
National Hospital, Kawachi-machi, Japan, and
4
Division of Diabetes and Endocrinology, Department of Internal Medicine,
The Jikei University School of Medicine, Tokyo, Japan
HORIE, N., KOMIYA, H., MORI, Y. and TAJIMA, N. New Body Mass Index Criteria of
Central Obesity for Male Japanese. Tohoku J. Exp. Med., 2006, 208 (1), 83-86 ── In
recent years, intra-abdominal visceral fat leads to obesity-related complications. A simple
indicator that reflects the mass of visceral fat is also needed to enable practical screening
of patients. The present study was designed to establish new body mass index (BMI) criteria of central obesity for male Japanese. The subjects were 516 men aged from 19 to 80
years old who were examined at the physical examination center in the regular health
check conducted by their company. Correlations between visceral fat area (VFA) or subcutaneous fat area (SFA) and BMI in the subjects were investigated. Receiver Operating
Characteristics (ROC) curve was used to find out the optimal cut-off values of BMI to predict central obesity. We compared the percentile ranks corresponding to VFA of 100 cm²,
BMI of 25 kg/m2 and new BMI criteria to check to see whether the present BMI criteria
classify correctly Japanese men as central obesity. Further evidence for the effectiveness
of BMI for VFA is needed. The correlation coefficient between VFA or SFA and BMI was
0.59 or 0.67, respectively. At the cut-off for BMI that maximized sensitivity and specificity for predicting central obesity was 24 kg/m². Moreover, the percentile value corresponding to VFA of 100 cm², BMI of 24 kg/m², and BMI of 25 kg/m² was the 53, 50 and 61 percentile, respectively. It is necessary to lower a cut-off point for central obesity from BMI
of 25 kg/m² to 24 kg/m². ──── VFA; ROC curve; optimal cut-off value of BMI; percentile
© 2006 Tohoku University Medical Press
Body mass index (BMI) is an index widely
used to define obesity. The World Health
Organization (WHO) sets the value ≧ BMI 30
kg/m² as obesity (World Health Organization
1998). However, with the obesity value defined
by the WHO as ≧ BMI 30 kg/m², no more than
2-3% Japanese population are consider as obesity
(Yoshiike et al. 1998). Moreover, Japanese with
Received July 4, 2005; revision accepted for publication October 24, 2005.
Correspondence: Hideaki Komiya, Department of Exercise Physiology, Utsunomiya University, 350 Mine,
Utsunomiya 321-8505, Japan.
e-mail: [email protected]
83
84
N. Horie et al.
even mild obesity tend to have obesity-related
complication (Egusa et al. 1993; Fujimoto et al.
1995). From these findings, in 2002, the Japan
Society for the Study of Obesity (JASSO) proposed that those with value ≧ BMI 25 kg/m²
should be considered as obese (The Examination
Committee of Criteria for “Obesity Disease” in
Japan, Japan Society for the Study of Obesity
2002).
In recent years, it is suggested that adipocytes secrete various biologically active proteins
which influence arteriosclerotic cardiovascular
disease (Funahashi et al. 1999; Manabe et al.
1999). The National Cholesterol Education
Programme’s Adult Treatment Panel III (NCEPATP III) outlined specific diagnostic criteria for
the diagnosis of the metabolic syndrome (Expert
Panel on Detection, Evaluation, and Treatment of
High Blood Cholesterol in Adults 2001). This is
probably suggested that central obesity is the centerpiece of the metabolic alterations.
The aim of the present study was to determine new BMI criteria of central obesity among
the Japanese.
order to predict central obesity among the Japanese by
using Receiver Operating Characteristics (ROC) curve.
Moreover, in this study, we compared the percentile
ranks corresponding to VFA of 100 cm², BMI of
25 kg/m² and new BMI criteria to check to see whether
the present BMI criteria classify correctly Japanese men
as central obesity.
RESULTS
We found that the relative frequency of BMI,
TC, Glu and VFA was little high compared with
the data in Japanese adult men. BMI closely correlated with SFA (0.67), but had a correlation with
VFA (0.59). The BMI corresponding to VFA of
100 cm² was 24 (Fig. 1). The cutoffs for BMI
corresponding to the criterion value with the best
tradeoff (maximizing the sum of the sensitivity
and specificity) are presented in Table 2. The sensitivity and specificity were 0.7654 and 0.7363 at
BMI of 24 kg/m². Moreover, the percentile value
corresponding to VFA of 100 cm², BMI of 24 and
25 kg/m² was the 53, 50 and 61 percentile, respectively.
MATERIALS AND METHODS
Our study subjects comprised 516 men (aged ranged
from 19 to 80) who visited the physical examination center, from 2001 to 2004. Physical and laboratory examinations included height, body weight, BMI, waist circumference (W), total cholesterol (TC), triglycerides
(TG), HDL cholesterol (HDL-c), blood glucose (Glu),
and blood pressure. BMI was calculated as weight (Kg)
divided by the square of height (m). Blood sampling and
blood pressure measurement were performed early in the
morning in fasting conditions. Computed tomography
(CT) images taken at the navel level were used for evaluation of visceral fat area (VFA) and subcutaneous fat area
(SFA). The measurement is according to the Tokunaga
et al.’s method (1983) in which the VFA-SFA ratio is calculated as the V/S ratio. All subjects were fully informed
of the procedures, risk and discomforts involved in performing the CT scan of the abdomen. And the measurements were carried out in accordance with the 1964
Declaration of Helsinki.
Correlation coefficients were used to quantify the
relation between the VFA or SFA and BMI. We also
aimed to find out the optimal cut-off value of BMI in
Fig. 1. ROC curve for prediction of central obesity
for BMI.
*
■, indicate cut-off value of BMI 24.
New Body Mass Index Criteria of Central Obesity for Male Japanese
85
TABLE 1. The physical characteristics and the criteria for determination
Variables*
Mean ± S.D.
Criteria**
Relative frequency (%)
BMI (kg/m²)
W (cm)
TC (mmol/liter)
TG (mmol/liter)
HDL-c (mmol/liter)
Glu (mmol/liter)
SBP (mmHg)
DBP (mmHg)
VFA (cm²)
SFA (cm²)
24.4 ± 3.6
81.8 ± 9.8
5.4 ± 0.9
1.7 ± 1.1
1.4 ± 0.4
6.5 ± 1.9
130.0 ± 17.5
78.6 ± 11.8
96.6 ± 47.9
121.4 ± 54.6
≧ 25 kg/m²
39.5
≧ 5.69 mmol/liter
38.2
35.5
14.9
19.8
26.6
16.3
47.1
≧ 1.69 mmol/liter
< 1.03 mmol/liter
≧ 6.99 mmol/liter
≧ 140 mmHg
≧ 90 mmHg
≧ 100 cm²
BMI, body mass index; W, waist circumference; TC, total cholesterol; TG, triglycerides; HDL-c,
HDL cholesterol; Glu, blood glucose; SBP, systolic blood pressure; DBP, diastolic blood pressure;
VFA, visceral fat area; SFA, subcutaneous fat area.
**
Criteria, based on the Japan Society for the Study of Obesity in 2000.
*
TABLE 2. ROC analysis for prediction of central obesity for BMI
BMI 23
BMI 23.5
BMI 24
BMI 24.5
BMI 25
BMI 25.5
BMI 26
Sensitivitya
Specificityb
False positivec
False negatived
Concordance rate (%)
0.9012
0.8272
0.7654
0.6996
0.6584
0.5720
0.4527
0.5421
0.6630
0.7363
0.7949
0.8388
0.8755
0.9084
0.4579
0.3370
0.2637
0.2051
0.1612
0.1245
0.0916
0.0988
0.1728
0.2346
0.3004
0.3416
0.4280
0.5473
71
74
75
75
75
73
69
Central obesity who were classified correctly as central obese by BMI present the true-positive cases.
Non-central obese subjects classified correctly as non-central obese represent the true-negative cases.
c
Non-central obese subjects classified as central obese represent false-positive cases.
d
Central obese subjects classified as non-central obese represent false-negative cases.
a
b
DISCUSSION
Today, VFA can be measured accurately with
CT (Tokunaga et al. 1983). However, the techniques are expensive and are not widely used outside large clinical or research settings. More
recently, it has been suggested that the waist circumference itself may be a better indicator for
central obesity. However, the waist circumference is not routinely measured in every clinic.
Thus, the purpose of the current study is to establish a new BMI criteria of central obesity.
ROC curve means that the index and plot is
useful as a screening test if it is drawn near the
upper left-hand corner. Therefore it can be practically assumed that the BMI screening criterion is
24. If we used the cut-off value of BMI equal to
25, about 34% of central obesity would be considered to be false-negative. Moreover, the percentile value corresponding to VFA of 100 cm², BMI
of 24 kg/m², and BMI of 25 kg/m² was the 53, 50
and 61 percentile, respectively. With the use of
the standard value of BMI of 25 kg/m², Japanese
men are not classified correctly as central obesity.
86
N. Horie et al.
It is necessary to lower a cut-off point for central
obesity from BMI of 25 kg/m² to 24 kg/m².
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