Lipoprotein Metabolism, Insulin Resistance, and Adipocytokine Levels in Japanese Female Adolescents With a Normal Body Mass Index and High Body Fat Mass

Noriaki Kishimoto, Koichi Okita, Shingo Takada, Ichiro Sakuma, Yasuaki Saijo, Hitoshi Chiba, Kojiro Ishii, Reiko Kishi, Hiroyuki Tsutsui
2009 Circulation Journal  
besity is defined as an excessive accumulation of body fat and has been established as a risk factor for diabetes, hypertension, hyperlipidemia, ischemic heart disease and cerebrovascular disease. 1,2 The incidence of obesity in Japan has been increasing every year and is currently reported to be 28.9% for men and 23.1% for women, 3 which is lower than in Western countries, but the percentage of obesity in Japanese men of all generations has increased 1.5-fold over the past 20 years, probably
more » ... 0 years, probably because of the Westernization of lifestyle, particularly the consumption of high-fat food and lack of exercise. Obesity evaluated by body mass index (BMI) in Japanese women older than 60 years has increased, whereas that in women aged in their 20 s to 50 s has been disproportionately decreasing. 4,5 Does this mean that obesity in young Japanese females is decreasing? However, a higher BMI is not always consistent with excess body fat mass (BFM), thus an exact evaluation of the body composition of Japanese female adolescents is needed and was the aim of the present study, which was designed to both determine whether young women with a normal BMI have a normal body fat mass and to assess their lipid profiles, lipoprotein metabolism, insulin resistance and adipocytokine levels. Methods Study Subjects The study subjects were 157 healthy women students (mean age, 21 years) from Hokkaido University. Women who had endocrine disease, diabetes mellitus, hyperlipidemia, or hypertension were excluded. This study conformed to the principles of the Declaration of Helsinki, and written informed consent was given by each subject. The protocol was approved by the Ethics Committee of Hokkaido University Graduate School of Education. Body Fat Composition All subjects were measured for height, weight, waist circumference (at the slimmest part of the waist as viewed from the front) and hip circumference (at the widest part). BMI was calculated as body weight (kg)/(height in m) 2 . A normal BMI was defined as 18.5-25 kg/m 2 . 6 In addition, BFM, central fat mass (CFM), peripheral fat mass (PFM) and lean body weight (LBW) were measured by dual energy X-ray absorptiometry (DEXA) with a QDR-2000 (Hologic Inc, Boston, MA, USA). 7 The body fat percentage was calculated as BFM (kg)/weight (kg) and the range of Background: The prevalence of obesity is gradually increasing in Japan, but in women aged in their 20 s to 50 s it has been disproportionately decreasing. However, the exact body composition of this subset of the population has not been elucidated. Methods and Results: Body composition was determined using whole-body dual energy X-ray absorptiometry and metabolic parameters in 157 Japanese female university students (21.1±1.9 years); 31 women had a normal body mass index (BMI), but an increased body fat mass (BFM). Only the 31 had significantly higher low-density lipoprotein-cholesterol levels (90.5 vs 99.0 mg/dl, P<0.01) and leptin concentration (7.0 vs 4.6 ng/ml, P<0.05) and lower high-density lipoprotein-cholesterol (80.4±15.1 vs 73.5±14.5 mg/dl, P<0.01) than females with normal BMI and normal BFM. Conclusions: A considerable number of young Japanese women with a normal BMI have excess BFM and relatively higher lipid and leptin levels. These findings may provide an important basis for future epidemiological surveys and studies. (Circ J 2009; 73: 534 -539)
doi:10.1253/circj.cj-08-0381 pmid:19145038 fatcat:czunrito6vd2pm3zm2qmntzjqa