Discordance in the decline in regional lean and bone mass with advancing age.

AIM: To investigate whether regional mineral-free lean mass (lean mass) and bone mineral density (BMD) decrease equally with advancing age. METHODS: Subjects were 420 premenopausal women and 239 postmenopausal women with right-side dominance. Age, height, weight, and body mass index were recorded. Lean mass of the arms, trunk and legs were measured by dual-energy X-ray absorptiometry (DEXA). BMD of the same segmental regions was measured by DEXA. RESULTS: Trunk and bilateral leg lean mass were inversely correlated to age (r = -0.240, P < 0.0001, -0.167, P < 0.0001, and -0.183, P < 0.0001, respectively), but arm lean mass did not decrease with aging. Regional lean mass was positively correlated to regional BMD (r = 0.284-0.449, P < 0.0001). BMD was inversely correlated to age in all segmental regions (r = -0.586 to -0.449, P < 0.0001). CONCLUSIONS: Decline in regional lean mass and decline in BMD with advancing age are discordant. Arm lean mass may not contribute to 'age-related decline' in arm BMD, because arm lean mass does not decrease with advancing age in the general population of women.

Age-related change in the strength of correlation of lumbar spine bone mineral density with other regions.

OBJECTIVES: To investigate whether the strength of correlation of lumbar spine bone mineral density (BMD) with other regions differs with age. METHODS: Subjects were 336 premenopausal women aged 20-49 years and 218 postmenopausal women aged 50-69 years with right-side dominance. Age, height, weight, and years since menopause (YSM) were recorded. Subjects were classified into five subgroups at 10-year increments. BMD of the arms, lumbar spine (L2-4), pelvis, legs, and total body were measured by dual-energy X-ray absorptiometry (DEXA). RESULTS: Regional and total body BMD did not differ among women aged in their 20s, 30s, and 40s. However, in women aged over 50, regional and total body BMD gradually decreased with age. The strength of correlation of lumbar spine BMD with the left arm, right arm, left leg, right leg, and total body BMD gradually increased with advancing age (r=0.422-0.715, 0.376-0.714, 0.476-0.721, 0.491-0.734, and 0.642-0.800, respectively). However, the strength of correlation of lumbar spine BMD with pelvis BMD remained unchanged (r=0.512-0.622). CONCLUSIONS: Correlation of lumbar spine BMD with extremities BMD gradually strengthens with advancing age, while higher correlation of lumbar spine BMD with pelvis BMD remains unchanged. When lumbar spine BMD is predicted using values at sites such as forearm BMD, we should consider the patient's age.

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

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/Ht(2)) were recorded. Body fat mass, percentage of body fat, body fat mass/Ht(2), LBM, LBM/Wt, LBM/Ht(2), 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/Ht(2) were positively correlated with TBBMD. However, body fat mass and body fat mass/Ht(2) 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.

Inverse relationship between the changes in trunk lean and fat mass during gonadotropin-releasing hormone agonist therapy.

OBJECTIVE: The aim of the present study was to investigate the relationship between the changes in lean and fat mass during gonadotropin-releasing hormone agonist (GnRH agonist) therapy. METHODS: Subjects were 24 premenopausal women (mean age, 39.5+/-9.4 years; range, 32-52 years) with uterine leiomyomas. They were given GnRH agonist (leuprorelin acetate, 3.75 mg) monthly for 4 months. Age and height were recorded. Body weight, regional and total body composition, and the ratio of trunk fat mass to leg fat mass (trunk-leg fat ratio) were assessed by whole body scanning with dual-energy X-ray absorptiometry. Changes in these variables were investigated. Relationships between the changes in regional lean and fat mass were investigated using Pearson's correlation test. RESULTS: Trunk fat mass significantly increased from 8616+/-3538 to 9265+/-3526 g (P<0.01) and trunk-leg fat ratio significantly increased (1.02+/-0.39 to 1.07+/-0.39, P<0.05). Trunk lean mass significantly decreased from 18,509+/-2602 to 17,916+/-2402 g (P<0.01). However, body weight, and lean and fat mass component in the extremities did not change. Change in trunk fat mass was inversely correlated with change in trunk lean mass (r=-0.439, P<0.05), but such relationships were not observed in arm and leg regions. CONCLUSION: Inverse relationship between the changes in trunk lean and fat mass is observed during GnRH agonist therapy.

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. METHODS: Women with polycystic ovary syndrome (PCOS) were excluded from the study. Eighty-three obese women with a body mass index (BMI, Wt/Ht2) of more than 25 kg/m2 were classified into two groups according to their menstrual status: one with menstrual disorders (n = 39; mean age +/- standard deviation, 31.6 +/- 4.9 years) and the other group (controls) with regular menstruation (n = 44; 32.2 +/- 4.4 years). Age, age at menarche, height, weight, and BMI were recorded. Trunk fat mass, leg fat mass, the ratio of trunk to leg fat mass amount (trunk-leg fat ratio), body fat mass, and the percentage of body fat were measured by whole-body scanning with dual-energy X-ray absorptiometry. Baseline characteristics and anthropometric variables were compared between the two groups. RESULTS: Trunk-leg fat ratio in women with menstrual disorders was 1.48 +/- 0.29, which was significantly higher than that in controls (1.25 +/- 0.38, p < 0.01). Trunk fat mass was also significantly higher in women with menstrual disorders than in controls (14.9 +/- 4.1 kg vs. 12.9 +/- 3.8 kg, p < 0.05). However, BMI, percentage of body fat, body fat mass, and leg fat mass did not differ between the two groups. Age, age at menarche, height, and weight did not differ between the two groups. CONCLUSION: Upper body, but not lower body, obesity is associated with menstrual disorders.