Michiko Koda

Association of polymorphisms in the estrogen receptor α gene with body fat distribution

OBJECTIVE: To examine whether polymorphisms of the estrogen receptor (ER) α gene are associated with body fat distribution.DESIGN: Cross-sectional, epidemiological study of two single-nucleotide polymorphisms, a T → C (PvuII) and an A → G (XbaI), in the first intron of the ERα gene.SUBJECTS: A total of 2238 community-dwelling middle-aged and elderly Japanese population (age: 40–79 y).MEASUREMENTS: The ERα genotypes (by automated fluorescent allele-specific DNA primer assay system), anthropometric variables, fat mass (FM) and percentage FM (%FM) (by dual-energy X-ray absorptiometry).RESULTS: FM and waist were inversely associated with age (r=−0.630 and −0.504, respectively) in women with the GG genotype. On the other hand, waist circumference of the AA genotype was positively correlated with age (r=0.231). Thus, for middle-aged women (40–59 y) with the AG or GG genotype body mass index (BMI), %FM, FM, waist, hip and waist-to-hip ratio (WHR) were larger than those with the AA genotype. In particular, FM and waist were greater by 20% and 9%, respectively, for the GG genotype, compared to the AA genotype. Alternatively, FM and waist were smaller by 18% and 6%, respectively, in older women with the GG genotype, compared to the AA genotype. No effect was found among the A → G polymorphisms for men. For both genders, no difference was found in any variables among the TT, TC and CC genotypes with the exception of BMI of older men (60–79 y).CONCLUSION: No association was found between the ERα gene polymorphisms and body fat distribution in men. For women, the A → G polymorphism, in particular the GG genotype, may contribute to the development of upper-body obesity in middle-aged individuals, but may serve to decrease the whole-body and abdominal fat tissue of older individuals.

Association of the mitochondrial DNA 15497G/A polymorphism with obesity in a middle-aged and elderly Japanese population

Although polymorphism of the mitochondrial DNA 15497guanine/adenine (Mt15497G→A) leads to the Gly251Ser amino acid replacement on human cytochrome b, it is unknown whether functional alteration of the mitochondrion is induced by the Gly251Ser replacement. To see if an association exists between the Mt15497G→A polymorphism and obesity, we examined differences in body size, body composition, and regional body fat distribution between the two genotypes in middle-aged and elderly Japanese individuals (825 women and 906 men). The Mt15497 genotype was determined with an automated colorimetric allele-specific DNA probe assay system using the polymerase chain reaction (PCR) method. The Mt15497G→A polymorphism was detected in 3.5% (n=60) of all subjects: 2.8% (n=23) among women and 4.1% (n=37) among men. After adjusting for age and smoking, we found that body weight, body mass index, waist and hip circumferences, fat mass, fat-free mass, intra-abdominal fat and triglycerides were significantly greater in women with the A allele compared with the G allele (p=0.001–0.025). For men, waist to hip ratio was significantly greater (p=0.032), and waist circumference, intra-abdominal fat and triglycerides had a trend to be significantly greater (p=0.062–0.087) in subjects with the A allele compared with the G allele. These data suggest that the Mt15497 polymorphism may be associated with obesity-related variables and lipid metabolism.

Differences in the relationship between lipid CHD risk factors and body composition in Caucasians and Japanese

OBJECTIVES:To examine differences in the relationship between fat distribution and lipid coronary risk factors in Caucasian and Japanese population and further to determine whether the cut-points for body mass index (BMI) and waist circumference (WC) proposed by WHO and NHLBI are applicable to Japanese population as a predictor of a lipid risk factor abnormality or not.RESEARCH METHODS AND PROCEDURES:Subjects were 895 participants of the Baltimore Longitudinal Study of Aging in the US (BLSA) and 1705 participants of the Longitudinal Study of Aging by the National Institutes for Longevity Science in Japan (NILS-LSA). Subjects were divided into four demographic groups as younger (age<65 y) men and women, and older (age≥65 y) men and women. Blood total cholesterol, triglycerides, LDL- and HDL-cholesterol and anthropometry were measured. Regression coefficients of BMI and WC on risk factors, sensitivity and specificity of the BMI and WC cut-points for blood lipid abnormality, and mean values of blood lipids at BMI or WC cut-points were computed in both populations.RESULTS:Height, weight, WC and BMI were significantly greater in the BLSA than those in the NILS-LSA subjects. Total cholesterol, HDL- and LDL-cholesterol were significantly greater in the NILS-LSA than in the BLSA subjects. Sensitivities of BMI and WC cut-points were much lower in the NILS-LSA than in the BLSA subjects. Specificities of BMI and WC cut-points were higher in the NILS-LSA than in the BLSA subjects. Mean values of triglycerides, total cholesterol, HDL- and LDL-cholesterol at BMI=25 were significantly greater in the NILS-LSA than in the BLSA subjects. At the WC cut-point (94 cm for men, 80 cm for women), mean values of all lipids were significantly greater in the NILS-LSA than in the BLSA subjects with the exception of triglycerides in younger women.CONCLUSIONS:The Japanese subjects have smaller BMI and WC, worse total and LDL-cholesterol levels and better HDL-cholesterol levels compared to Caucasians. Sensitivities of BMI and WC for predicting lipid risk factor abnormality are much lower in Japanese. The cut-points for BMI and WC proposed by WHO and NHLBI may be too high for predicting an abnormality in triglycerides, total and LDL-cholesterol in Japanese. For detecting an abnormal HDL-cholesterol level, the BMI and WC cut-points may not be as beneficial for the Japanese population as for Caucasians.

Men who were thin during early adulthood exhibited greater weight gain-associated visceral fat accumulation in a study of middle-aged Japanese men: Visceral fat and weight gain after age 18

This study aimed to assess the relationship between weight gain from early adulthood and visceral fat accumulation.