Toshimichi Oki

Relative contribution of lean and fat mass component to bone mineral density in males.

Abstract. We investigated the relative contribution of lean body mass (LBM) and body fat mass to bone mineral density (BMD) in 93 healthy Japanese male volunteers (mean age, 33.1 ± 6.9 years; range, 18–54 years). Age, height (Ht), weight (Wt), and body mass index (BMI, Wt/Ht2) were recorded. Body fat mass, percentage of body fat, body fat mass/Ht2, LBM, LBM/Wt, LBM/Ht2, and lumbar spine (L2–L4) and total body BMD (TBBMD) were measured by dual-energy X-ray absorptiometry. On the Pearson correlation test, LBM was positively correlated with L2–L4 BMD. LBM, LBM/Wt, and LBM/Ht2 were positively correlated with TBBMD. However, body fat mass and body fat mass/Ht2 were not correlated with lumbar spine and total body BMD. On the partial correlation test, LBM was still correlated with lumbar spine (r = 0.307, P < 0.05) and total body BMD (r = 0.545, P < 0.0001), irrespective of age and height, whereas body fat mass was not correlated with BMD of these sites (r = −0.069 and −0.169, respectively). We concluded that, in males, LBM is one of the significant determinants of BMD whereas body fat mass is a negligible BMD determinant.

Difference in the effect of adiposity on bone density between pre- and postmenopausal women.

OBJECTIVES Elevated bone mineral density (BMD) in obese women is partially attributable to the higher circulating estrogen levels derived from extraglandular aromatization in adipose tissue. However, it remains unclear whether there is an effect of overall adiposity on BMD in both pre- and postmenopausal women. The difference in the effect of overall adiposity on BMD between pre- and postmenopausal women was investigated. MATERIALS AND METHODS Subjects were 296 premenopausal women with regular menstruation and 233 postmenopausal women. Age, age at menarche, years since menopause (YSM, in postmenopausal women), weight, height, and body mass index were recorded. Total fat mass amount, lean mass amount, and percentage of body fat were measured by whole body scanning with dual-energy X-ray absorptiometry (DEXA). Lumbar spine BMD (L2-L4) was measured by DEXA. In each group, significant determinants of BMD were investigated using univariate and stepwise multiple regression analysis. RESULTS In postmenopausal women, YSM, lean mass amount, total fat mass amount, and height were significant determinants of BMD (R(2)=0.273, P<0.001). In premenopausal women, only two variables including lean mass amount and age at menarche were significant determinants of lumbar spine BMD (R(2)=0.110, P<0.001), but total fat mass amount and percentage of body fat were not significant determinants of BMD. CONCLUSION The effect of overall adiposity on BMD is more prominent in postmenopausal women than in premenopausal women.

Body fat distribution in women with polycystic ovary syndrome

Objective To investigate body fat distribution in women with polycystic ovary syndrome (PCOS). Methods Body weight, body mass index (BMI), and six indices of body fat measured by dual-energy x-ray absorptiometry were compared in 40 women with PCOS and 97 age-matched controls. The possible correlations between the body fat characteristics and serum androgen levels were evaluated in the 40 PCOS women. Body fat distribution was classified into upper- (N = 24) and lower-half body type (N = 16), and androgen levels and the incidence of hirsutism were compared in the two types. Results The BMI, body fat ratio, upper-half body fat ratio, and upper-half/lower-half body fat ratio were significantly higher in PCOS women than in controls. After adjustment for age, height, and body weight, the upper-half/lower-half body fat ratio was still significant (P < .001). The PCOS subjects exhibited a significant positive correlation between the upper-half/lower-half body fat ratio and dehydroepiandrosterone-sulfate (DHEA-S) levels (r = 0.607, P < .01) as well as testosterone levels (r = 0.585, P < .05). Dehydroepiandrosterone-sulfate and testosterone levels were significantly higher in those with the upper-half body type than in those with the lower-half body type (P < .001). After adjustment for confounding variables, only DHEA-S was still significantly higher in this body type (P < .05). Conclusion Serum DHEA-S levels seem to be associated with upper-half body fat distribution in women with PCOS, irrespective of body weight.

The effect of body composition on bone density in pre- and postmenopausal women

OBJECTIVES To investigate the relative contribution of body composition (lean and fat) to bone mineral density (BMD), 196 premenopausal and 128 postmenopausal Japanese women were enrolled. METHODS Total fat mass, total lean mass, lumbar BMD (L2-L4), and total body BMD were measured by dual-energy X-ray absorptiometry (DEXA, Hologic QDR 2000, MA. USA). Physical characteristics were also recorded for each subject. Correlation between BMD and variables were calculated for each of the two groups in single and stepwise regression analyses. RESULTS Total lean mass was significantly higher in premenopausal women than postmenopausal women (P < 0.0001), while body weight, body mass index, and total fat mass were not different between the two groups. In stepwise regression analysis, total lean mass was the most powerful determinant of lumbar BMD and total body BMD in premenopausal women. In postmenopausal women, total fat mass was the most significant determinant of lumbar BMD, while total lean mass was the most significant determinant of total body BMD. CONCLUSIONS These findings suggest that there is a difference between pre- and postmenopausal women in the relative contribution of lean and fat mass. Total lean mass is the most significant determinant of BMD in premenopausal women. On the other hand, total fat mass may have some advantages in maintaining BMD in postmenopausal women.

The effect of menopause on regional and total body lean mass

OBJECTIVES To investigate the effect of menopause on regional and total body lean mass. METHODS Evaluation of 123 healthy premenopausal women (40.6 +/- 10.8 years) and 123 healthy postmenopausal women (61.8 +/- 7.5 years). All subjects were right side dominant. Regional (head, bilateral arms, trunk, and bilateral legs) and total body lean mass were measured using whole-body scanning by dual-energy X-ray absorptiometry. Baseline characteristics including age, height, weight, and menopausal state were recorded. These variables were compared between pre- and postmenopausal women. In all subjects, correlations between regional or total body lean mass and baseline characteristics were investigated using univariate and multiple regression analyses. RESULTS Height, and lean mass of the trunk, bilateral legs and total body were significantly lower in postmenopausal women than in premenopausal women, while lean mass of the bilateral arms did not differ between the two groups. On univariate regression analysis, bilateral arms lean mass was positively correlated with height (P < 0.001). Trunk, bilateral legs, and total body lean mass were inversely correlated with age and menopausal state (P < 0.001), but were positively correlated with height (P < 0.001). After adjusting for age and height, trunk lean mass was still correlated with menopausal state (P < 0.01). CONCLUSIONS Menopause induces lean mass loss, independent of aging and height. Trunk lean mass is more prone to decline with menopause than lean mass of other sites.

Relationship between body fat distribution and bone mineral density in premenopausal Japanese women

Objective To investigate the relationship between body fat distribution and bone mineral density (BMD). Methods Subjects were 282 premenopausal women (mean age ± standard deviation [SD], 38.8 ± 8.5 years; range, 20–51 years) with regular menstrual cycles. Baseline characteristics included age, age at menarche, height, weight, body mass index ([BMI], weight/height2), and parity. Anthropometric characteristics including the ratio of trunk fat mass to leg fat mass (trunk–leg fat ratio), percentage of body fat, and total body lean mass were measured by whole-body scanning with dual-energy x-ray absorptiometry. Lumbar spine BMD (L2–4) was also measured by dual-energy x-ray absorptiometry. Correlations of BMD to baseline and anthropometric characteristics were investigated using univariate and multivariate analysis. Results Although height, trunk–leg fat ratio, and total body lean mass were positively correlated with lumbar spine BMD (r = .18, P < .01; r = .17, P < .01; and r = .25, P < .001; respectively), age at menarche was inversely correlated with BMD (r = −.19, P < .01). On multivariable analysis, trunk–leg fat ratio, height, age at menarche, and total body lean mass were still independently correlated with lumbar spine BMD (P < .05). However, total fat mass was not correlated with BMD. Conclusion Upper body fat distribution rather than overall adiposity is associated with lumbar spine BMD in premenopausal women. Humoral factors associated with body fat mass appear to influence lumbar spine BMD.

Lean body mass and bone mineral density in physically exercising postmenopausal women

OBJECTIVES To investigate whether the relative contribution of body composition (lean and fat mass component) to postmenopausal bone mineral density (BMD) differs between women participating in physical exercise and sedentary women. METHODS Subjects were 45 postmenopausal women participating in regular physical exercise and 89 sedentary controls aged 50-60 years. Baseline characteristics included age, height, weight, body mass index (BMI, Wt/Ht(2)), age at menopause, and years since menopause (YSM). Body fat mass, percentage of body fat, lean body mass, and lumbar spine BMD (L2-4) were measured by dual-energy X-ray absorptiometry. RESULTS Although age, height, weight, BMI, and YSM did not differ between the two groups, lean body mass and lumbar spine BMD were significantly higher (P<0.05 and <0.001, respectively), while body fat mass and percentage of body fat mass were significantly lower in exercising women than in sedentary controls (P<0.05 and <0.05, respectively). In exercising women, BMD was positively correlated with lean body mass (r=0.415, P<0.01) but not with body fat mass (r=0.155, NS). Conversely, in sedentary controls, BMD was correlated with body fat mass (r=0.251, P<0.05) and lean body mass (r=0.228, P<0.05). CONCLUSIONS Lean body mass is a more significant determinant of postmenopausal BMD in physically exercising women than in sedentary women.

The contribution of menopause to changes in body-fat distribution.

Objective: To investigate whether menopause contributes to changes in body‐fat distribution, irrespective of aging or obesity.

Relationship of upper body obesity to menstrual disorders

Background. The purpose of the present study was to investigate the relative contribution of upper and lower body obesity to obesity‐related menstrual disorders.

Relationship of androgens to muscle size and bone mineral density in women with polycystic ovary syndrome.

OBJECTIVE To investigate the relationship of androgens to regional muscle size and bone mineral density (BMD) in women with polycystic ovary syndrome (PCOS). METHODS Seventy‐one amenorrheic and right‐side dominant women with PCOS (mean age ± standard deviation 28.1 ± 6.7 years) were enrolled. Baseline characteristics included age, height, weight, and body mass index (BMI). Regional BMD and lean mass were measured by whole‐body scanning with dual‐energy x‐ray absorptiometry. Serum levels of testosterone, dehydroepiandrosterone sulfate (DHEAS), and androstenedione were measured by radioimmunoassay. Correlations between regional BMD and variables were investigated using a Pearson correlation test and multiple regression analysis. RESULTS Serum testosterone levels correlated significantly with lean mass of the left arm, right arm, trunk, left leg, and right leg (r = .34, P < .05 to r = .50, P < .01). Regional lean mass correlated significantly with respective regional BMD (r = .30, P < .05 to r = .68, P < .001). These relationships remained significant after adjusting for age, height, and weight. Serum testosterone levels were not correlated with BMD of the bilateral arms and lumbar spine. Although serum testosterone levels correlated with leg BMD (r = .34, P < .05 to r = .45, P < .01), significance did not persist after adjusting for respective regional lean mass. CONCLUSION Testosterone influences regional BMD through increasing regional muscle mass in women with polycystic ovary syndrome.