Familial resemblance of radial bone mass between premenopausal mothers and their college-age daughters

Summary The influences of heredity and environmental factors on radial bone mass were evaluated in 84 premenopausal mothers with their biological daughters (ages 18–22). Mid- and distal radial bone mineral content (BMC) and density (BMD) were assessed using single-photon absorptiometry. As a group, the daughters (mean age 18.6 years) had 5–10% less bone mass at both the distal and midradial sites than their mothers (mean age 44.2 years). Familial resemblance estimates showed significant relationships between mothers and daughters for mid-and distal BMC and BMD after considering the influence of body mass index (BMI). Daughters with a maternal family history of osteoporosis had 6–7% lower but nonsignificant values of mid- (P=0.086) and distal BMC (P=0.075) compared to values of women with a negative family history, whereas mothers with a positive family history had 3–4% lower (NS) values of distal and mid-BMC compared to those of mothers with a negative family history after adjustment for BMI. Multiple regression analyses showed BMI to be the most important determinant of the bone values of the mothers, and both BMI and dietary calcium intake were found to be significant for the daughters. The findings of this study suggest that hereditary contributions from the mothers play an overwhelmingly critical role in the accrual of bone mass by their daughters by ages 18–22, but that environmental influences on bone consolidation during the premenopausal decades may be more important in promoting optimal (peak) bone mass and thereby may help to delay the postmenopausal onset of osteoporotic fractures.     

Adiponectin is a predictor of bone mineral density in middle-aged premenopausal women

Summary

Adipose-modulated biochemical signal that explains some of the association between fat mass and bone mineral density (BMD) is adiponectin. The results demonstrated an independent association between adiponectin and BMD, while the influence of adiponectin on bone mineral content is mediated by fat free mass in middle-aged women.

Introduction

Positive association between fat mass (FM) and bone mineral density (BMD) is mediated by biochemical factors.

Methods

The relationship between plasma adiponectin concentration and BMD in 98 sedentary premenopausal women aged 38–49 years with a body mass index range of 20.0–42.1 kg/m² was examined. Different body composition and blood biochemical parameters were measured to adjust for possible confounding variables.

Results

The association between adiponectin and BMD values (total BMD: ß?=??0.919; p?=?0.0001, femoral neck BMD: ß?=??0.925; p?=?0.0001 and lumbar spine BMD: ß?=??0.912; p?=?0.0001) was independent of the influences that measured body composition, hormonal and insulin resistance factors may exert on BMD (p??0.21).

Conclusions

Adiponectin is an independent predictor of BMD, while its independent contribution to the interindividual variance in measured values is only modest. The influence of adiponectin on total BMC is mediated or confounded by FFM in middle-aged premenopausal women.

     

Health and hormonal characteristics of premenopausal women with lower bone mass

Summary A study of clinical renal and endocrinologic status was undertaken to determine whether the lowest maximal bone mass observed in premenopausal women, aged 20–40 years, was a result of undiagnosed disease or represented a continuum of measurement in young adult women. A clinical sample (n=53) was generated from an epidemiologic cross-sectional study (n=535) designed to characterize correlates of maximal bone mass. Cases were 28 premenopausal women whose femoral bone mass as in the lowest 5th percentile of the distribution, <0.75 g/cm² at the femoral neck. Controls were 25 randomly selected premenopausal women whose femoral bone mass was within 1 SD of the mean of the femoral bone mass distribution. There was no indication of increased frequency of disease among the cases as compared with the controls. No occult hypogonadism, thyrotoxicosis, hyperparathyroidism, myeloma, or renal insufficiency was observed to explain lower bone mass measurement. However, cases had significantly lower estradiol levels (75 versus 106 pg/ml,P<0.05) and higher luteinizing hormone levels (3.8 versus 3.1 mIU/ml,P<0.07) than controls. Though preliminary, these findings suggest that lower estradiol levels may contribute to significant differences in bone mass even among healthy women at the time of maximal bone accumulation.     

Age-related loss of trabecular bone in premenopausal women: A biopsy study

Summary We measured the trabecular bone volume (TBV) of 62 iliac crest biopsies taken from women admitted to lymphoma protocols at Stanford University between 1970–1981. All subjects were active, cycling premenopausal women, with bone marrows that were negative for tumor. Disease status was stage III or less in 90% of the subjects. Trabecular bone volume was negatively correlated with age, and the annual predicted loss of bone was 0.14–0.18% TBV, or 0.7% of the original bone volume. In addition, there was a substantial range of normal TBV at any given age, evident even during adolescence. This study demonstrates that TBV is lost from iliac crest throughout adult life. The large spread in TBV indicates further that factors operating during adolescence or even earlier may have an important impact on skeletal mass.     

Association between bone mineral density,lean mass,and fat mass among healthy middle-aged premenopausal women: a cross-sectional study in southern Sri Lanka

Associations between lean mass, fat mass, and bone mass have been reported earlier; however, most of those studies have been done in Caucasian populations, and data from Asian countries, especially those in South Asia, are limited. We examined the associations between lean mass, fat mass, bone mineral density (BMD), and bone mineral content (BMC), determined by dual-energy X-ray absorptiometry technology, in a group of healthy, middle-aged, premenopausal female volunteers. The mean (SD) age of the women (n = 106) was 42.1 (6.1) years and the mean (SD) body mass index was 24.3 (3.6) kg/m². Total body BMD, total body BMC, and BMD in total spine, total hip, and femoral neck showed statistically significant partial correlations (adjusted for age) with total fat mass (r = 0.19–0.43, P < 0.05) and lean body mass (r = 0.28–0.54, P < 0.05). Truncal fat mass correlated positively with total body BMC and BMD at total hip and femoral neck (r = 0.33–0.40, P < 0.001). When a stepwise regression model was fitted, lean mass remained the strongest predictor of total body BMD, total body BMC, and total spine BMD (regression coefficients = 0.004–0.008 g/cm² per 1-kg change in lean mass, P < 0.001). Similarly, crude BMD and BMC increased across the tertiles of lean mass (P trend < 0.05). We show that lean mass is the strongest predictor of total body BMC and BMD at different sites, although positive correlations with fat mass also exist.     

Deterring bone loss by exercise intervention in premenopausal and postmenopausal women

Summary This study investigated the efficacy of 4 years of exercise intervention in deterring bone loss in middle-aged women, and is a correction and extension of previously published data. Sixty-two control subjects (mean age 50.8) and 80 exercise subjects (mean age 50.1) completed a 4-year study. Subjects exercised three times a week, 45 minutes per session. Bilateral radius, ulna, and humerus bone mineral content (BMC) and width (W) were measured on each subject 11 times over the 4-year period. The two groups did not differ initially in age, height, or weight, but the control group had a greater maximum VO₂ (ml/kg/min) than the exercise group. Slopes and intercepts of the bone variables vs. time were determined for each subject, and these values were used for between-group comparisons of loss. The control group BMC and BMC/W declined significantly in all three bones in both arms. The exercise group rate of decline was significantly less than that of the control group for 12 of the 18 bone variables. The greatest effect of the exercise intervention was on the ulna and radius. Exercise subjects lost significantly less than control subjects in left and right ulna and radius BMC and BMC/W, and left ulna and radius W. Lesser differences between groups were observed in the humerus. BMC and W loss rates of the left humerus were reduced in the exercise group, with no difference between exercise and control subjects in the other humerus variables. To determine if menopausal status influenced the response to exercise, we analyzed the difference between groups for premenopausal and postmenopausal subjects separately. Regardless of menopausal status, exercise subjects had lower bone loss rates than control subjects. In both premenopausal and postmenopausal subjects, exercise reduced bone loss significantly for 10 of the 18 bone variables. It can be concluded that physical activity significantly reduces bone loss in the arms of middle-aged women.     

Bone mineral density in Norwegian premenopausal women

The aims of this study were: 1) to determine bone mineral density (BMD) in different age groups, 2) to determine the prevalence of low BMD, and 3) to determine the possible association between BMD and a number of risk factors in Norwegian premenopausal women. BMD of the lumbar spine (L₂–L₄), total body, and the hip (total femur, femur neck, and trochanter) were measured using dual-energy X-ray absorptiometry (Prodigy, Lunar) in 145 randomly selected women aged 13–39 years. Information on other factors thought to influence BMD was obtained through questionnaire and a clinical interview. The group aged 25–29 years had the highest mean BMD in the total body, lumbar spine, and total femur while the group aged 13–19 years had the highest mean BMD in the femur neck and the trochanter. The mean BMD values of Norwegian premenopausal women were 3.4–5.1% higher than US/European reference data (P<0.05). Five percent of the study sample aged 20–39 years were defined with low BMD (Z-score <–2) using the standard values from this study. Weight-bearing physical activity, body weight, body height, and age were positively associated with BMD, whilst menstrual dysfunction and previous pregnancy were associated with lower BMD in some of the measurement sites. The results show that the factors associated with BMD are extensive, and the strategies to prevent low BMD have to be multifactorial. A follow-up study should be conducted on the study sample to investigate actual mean BMD values and BMD changes through time.     

Walking at work and bone mineral density of premenopausal women

The objective of this cross-sectional study was to determine whether habitual physical activity such as daily walking at work affects bone mineral density (BMD) in healthy premenopausal women. Thirty-one letter or newspaper carriers and 30 sedentary (non-exercising) office workers were screened out from 167 subjects working in the public post office and a private newspaper publishing company. BMD was measured with a dual-energy X-ray densitometer at the lumbar spine (L2–4), femoral neck, distal femur, patella, proximal tibia, calcaneus and distal radius. In addition, maximal isometric strength, cardiorespiratory fitness, anthropometry, 4-day dietary record and daily occupational work load were assessed. During one work shift the carriers' mean walking distance was 5926 m, with 68 flights of stairs walked, and their mean heart rate was 105 beats/min (114 beats/min during the delivery). The corresponding figures for the office workers were significantly lower: 1895 m, 10 flights and 82 beats/ min, respectively. Neither the BMD values adjusted for body mass index (kg/m²) and calcium intake nor the indices of physical performance capacity showed significant differences between the groups. Consequently, habitual daily walking and stair climbing by healthy premenopausal women appeared to be insufficient exercise stimulus to increase considerably the BMD or aerobic and muscular fitness above the values found in a comparable group of sedentary office workers.     

Spinal bone mineral loss in estrogen-replete,calcium-replete premenopausal women

After peak bone mass in women is attained, the benefits of increased dietary calcium or supplemental calcium are uncertain. In a longitudinal, 4-year study we have investigated the effect of calcium intake on bone mineral in a group of 41 premenopausal women, aged 38–42 years at entry. Skeletal density was measured four times during the 4-year follow-up; spinal trabecular bone density (STBD) was measured by quantitative computed tomography, and midradius bone mineral density (RBMD) was measured by single photon absorptiometry. At baseline, no differences in bone density were observed among subjects in the highest and lowest quartiles of habitual dietary intake. Overall, STBD declined –0.86±0.15% per year (p<0.001), but RBMD did not decline. Total calcium intake (dietary calcium plus supplemental calcium) did not correlate with the rate of STBD loss. Serum estradiol level did not decrease during the study, and bone loss did not correlate with the mean estradiol level. We conclude that premenopausal women in the fifth decade lose about 1% of spinal trabecular mineral yearly, in spite of a normal serum estradiol level and ample calcium intake.     

Bone mineral density,sex steroids,and mineral metabolism in premenopausal smokers

Smoking is related to decreased bone mass and increased risk of osteoporotic fractures. However, the harmful effects of smoking on bone have not been well characterized. The purpose of this study was to assess the repercussions of smoking on bone mass in premenopausal women, and the relationship between these effects and parameters of mineral metabolism and hormone profile. We measured bone mineral density (BMD) in 101 premenopausal women (47 smokers, 54 nonsmokers) with dualenergy X-ray absorptiometry (DeXA) of the proximal femur and lumbar spine. In a subgroup of the sample (16 smokers, 15 nonsmokers) we measured biochemical indicators of mineral metabolism and hormone profile. BMD in the femoral neck, Ward's triangle, and the intertrochanter region was significantly lower in smoker (P<0.05) than in nonsmokers. Concentrations of sex hormone-binding globulin were higher, and free testosterone index (FTI) was lower (P<0.05) in smokers. We found no significant differences between the groups in parameters of mineral metabolism. Concentrations of dehydroepiandrosterone sulfate and free testosterone index were directly correlated with values of BMD in different sites. Our findings show that smoking by premenopausal women is associated with decreased BMD and characteristic changes in the hormone profile.     

Age and anthropometric determinants of radial bone mass in premenopausal caucasian women: A cross-sectional study

A sample of 181 healthy premenopausal Caucasian women, 20 to 50 years of age, was part of a cross-sectional study on the determinants of radial bone mineral content (BMC), bone width (BW) and areal bone mineral density (BMD) at two sites, the distal (Dis) or 5 mm-site (about 50% cancellous tissue) and the mid-radial (Mid) site (over 90% cortical tissue), as measured by single photon-absorptiometry. Women in their 20s (n=45) had significantly lower DisBMC and DisBW values than women in their 30s (n= 65) or 40s (n=71). No such trends were noted for any of the mid-radial measurements with increasing age. With age, height and weight included in the same regression equation, age remained the only significant positive predictor of all three distal variables, while height was the only significant positive predictor of the mid-radial variables. Body weight was not associated with any of the bone variables in this model. A low lean body mass (LBM) or low body mass index (BMI) was consistently correlated with significantly lower bone values at both radial sites. These data suggest that peak bone mass (PBM), for the distal and largely cancellous portion of the radius, was achieved later in adulthood (30s) than the mid-radial or mostly cortical portion of the radius in which PBM was achieved much earlier, probably in late adolescence.     

Peak bone mass, bone loss and risk of fracture

Both peak bone mass and bone loss contribute to subsequent fracture risk. Other variables such as architectural abnormalities, microdamage, geometric properties, and trauma probably contribute as well. Until the contribution of these other potentially important risk factors can be quantified, it will be difficult to determine precisely the relative importance of peak bone mass and subsequent bone loss in the etiology of fractures.     

One-year psoas training can prevent lumbar bone loss in postmenopausal women: A randomized controlled trial

Summary On the premise that bone response to exercise is locally controlled [1], we conducted a randomized trial to evaluate the effects of a 1-year training of psoas muscles (treatment group: TG) versus a 1-year training of deltoid muscles (control group: CG) on the lumbar trabecular bone mineral density (TBMD). TBMD was measured with computed tomography scan. Seventy-eight subjects were included and 67 completed the study. Intention to treat analysis revealed no significant change in TBMD from 0 to 12 months. Data analysis in the 67 remaining women, including both assiduous and nonassiduous subjects, revealed greater bone loss in CG than in TG although the difference was not significant. Similar analysis in a subgroup of subjects who performed the exercises assiduously (TG: n = 23, CG: n = 26) showed that the mean bone loss of all four vertebrae from 0 to 12 months was significantly greater in the CG (–8.87 ± 12.75 mg/cm³, mean ± SD) than in the TG (0.14 ± 11.21 mg/cm³, mean ± SD,P = 0.01). These results suggest that continuous 1-year psoas training can prevent lumbar bone loss in postmenopausal women and support the hypothesis of local action of physical activity.     

The association between vitamin D receptor gene polymorphisms and bone mineral density at the spine,hip and whole-body in premenopausal women

The genetic influence on bone mineral density (BMD) is thought to be mediated in part by alleles at the vitamin D receptor (VDR) locus. In order to assess the effect of VDR on BMD in premenopausal women, we studied 470 healthy white subjects, aged 44–50 years, participating in the Women's Healthy Lifestyle Project. Each participant was genotyped for theBsmI polymorphism at the VDR gene locus. BMD at the lumbar spine, hip and whole-body, and the whole-body soft tissue composition, were measured cross-sectionally using a Hologic QDR 2000 densitometer. The presence of a polymorphic restriction site at the VDR gene locus was specified asb, whereas absence of this site wasB. The frequency distribution of the VDR genotype was:bb, 20.6%;Bb, 39.1%; andBB, 40.2%. Spinal BMD (mean±SD) was significantly lower in women with VDR genotypeBB (1.038±0.11 g/cm²) as compared with those with genotypebb (1.069±0.12 g/cm²,p<0.05). Trochanter BMD was 2.7% lower in those with genotypeBB versusbb (0.685±0.10 g/cm² vs 0.708±0.09 g/cm²). A similar trend was shown at each subregion of the hip, but not at the whole-body. In premenopausal women, allelic status at the VDR locus contributed to variations in spinal and trochanteric BMDs, but the absolute difference in BMDs was small, amounting to 0.26 and 0.23 standard deviations, respectively. It is concluded that in this population of healthy premenopausal women there was a significant association between polymorphisms at the VDR gene locus and both spinal and trochanteric BMDs, yet no association was demonstrated for the whole-body BMD.     

Is postmenopausal bone loss an age-related phenomenon?

Summary Forearm bone mineral content (BMC), an index of skeletal mineralization, and lean body mass (LBM), an index of the muscle mass in the body, were calculated in 574 healthy, white subjects, aged 20–89 years. In women, there was no significant change in BMC with age until the menopause. Thereafter, a significant decline averaging 15% per decade was found up to the age of 70 years, after which it was 10% per decade. In men, there was a significant overall decline of about 4% per decade from the age of 20. When BMC was corrected for LBM, the age-related fall in men disappeared, while remaining without a significant trend in premenopausal women. This was, however, not the case in women after the menopause, where a significant decline of about 12% per decade was noted. These data clearly demonstrate that the major contribution to the well-known bone loss in postmenopausal women is not a simple age-related phenomenon. The development of osteoporosis must be due to some additional bone-diminishing effect on the female skeleton, most likely the absence of estrogen.     

Effects of high-impact exercise on bone mineral density: a randomized controlled trial in premenopausal women

Introduction: The purpose of this randomized controlled study was to assess the effects of high-impact exercise on the bone mineral density (BMD) of premenopausal women at the population level. Materials and methods: The study population consisted of a random population-based sample of 120 women from a cohort of 5,161 women, aged 35 to 40 years. They were randomly assigned to either an exercise or control group. The exercise regimen consisted of supervised, progressive high-impact exercises three times per week and an additional home program for 12 months. BMD was measured on the lumbar spine (L1–L4), proximal femur, and distal forearm, by dual-energy X-ray absorptiometry at baseline and after 12 months. Calcaneal bone was measured using quantitative ultrasound. Results: Thirty-nine women (65%) in the exercise group and 41 women (68%) in the control group completed the study. The exercise group demonstrated significant change compared with the control group in femoral neck BMD (1.1% vs –0.4%; p=0.003), intertrochanteric BMD (0.8% vs –0.2%; p=0.029), and total femoral BMD (0.1% vs –0.3%; p=0.006). No exercise-induced effects were found in the total lumbar BMD or in the lumbar vertebrae L2–L4. Instead, L1 BMD (2.2% vs –0.4%; p=0.002) increased significantly more in the exercise group than in the control group. Calcaneal broadband ultrasound attenuation showed also a significant change in the exercise group compared with the control group (7.3% vs –0.6%; p=0.015). The changes were also significant within the exercise group, but not within the control group. There were no significant differences between or within the groups in the distal forearm. Conclusions: This study indicates that high-impact exercise is effective in improving bone mineral density in the lumbar spine and upper femur in premenopausal women, and the results of the study may be generalized at the population level. This type of training may be an efficient, safe, and inexpensive way to prevent osteoporosis later in life.     

Age-Related Decline in Trabecular and Cortical Density: A 5-Year Peripheral Quantitative Computed Tomography Follow-Up Study of Pre- and Postmenopausal Women

This 5-year prospective study assessed changes in trabecular and cortical volumetric bone density at the non-weight-bearing radius and weight-bearing tibia among clinically healthy pre- and postmenopausal women. Altogether 79 premenopausal (mean age ± SD at baseline 33 ± 2 years) and 108 postmenopausal (68 ± 2 years) women participated in the baseline and follow-up measurements. Trabecular density (TrD) of the distal radius and tibia and cortical density (CoD) of the radial and tibial shafts were assessed by peripheral quantitative computed tomography (pQCT). Repeated measures analysis of variance was used to analyze differences of means and mean changes between the age groups. As expected, TrD and CoD values were greater among premenopausal than postmenopausal women. Changes in radial TrD were similar in both age groups: mean (95% confidence interval) TrD of the distal radius declined by 3.0 mg/cm³ (−0.9 to 7.0) and 5.1 mg/cm³ (1.8–8.5) in the younger and older age groups, respectively. The respective declines in TrD of the distal tibia were 4.1 mg/cm³ (2.1–6.0) and 2.8 mg/cm³ (1.2–4.3). Decline in CoD was greater in the older than younger age group at both the radial and tibial shafts (P < 0.001). The mean absolute declines in radial CoD were 33.3 mg/cm³ (27.9–38.7) and 49.4 mg/cm³ (44.9–53.9) in younger and older women, and the declines in tibial CoD were 16.5 mg/cm³ (12.6–20.2) and 28.1 mg/cm³ (25.0–31.2), respectively. In conclusion, volumetric TrD in the weight-bearing tibia and non-weight-bearing radius showed similar age-related declines among pre- and postmenopausal women, while the decline in CoD was greater among postmenopausal women.     

Effects of 1-year treatment with ipriflavone on bone in postmenopausal women with low bone mass

Ipriflavone (IP) (7-isopropoxyisoflavone), a synthetic isoflavone derivative, is active in both inhibiting bone resorption and enhancing osteoblast function. This property suggested its clinical use in the treatment of involutional osteoporosis, and in the prevention of postmenopausal bone mass loss. Forty postmenopausal women with low bone mineral content were enrolled and randomly treated for 12 months with IP 600 mg/day or placebo (PL), according to a double-blind, parallel group design. All patients wee also given an oral calcium supplementation (1 g/day). Bone mineral density (BMD) was measured at the spine (L₂–L₄) by dual-energy X-ray absorptiometry. Bone metabolism markers (serum calcium, phosphate, osteocalcin, and alkaline phosphatase, and urinary calcium, phosphate, and hydroxyproline) were assessed at the same times. After 12 months, a reduction of BMD was evidenced in the PL-treated group, at both the spine (–2.2%, P<0.01 vs baseline) and the forearm (–1.2%). In the IP-treated group, an increase of BMD was obtained (+1.2%, P<0.01 vs placebo, at the spine; +3%, not significant, at the forearm). Bone markers were in the normal range for postmenopausal women; no statistically significant modificantions were observed during the treatment period. Three patients were withdrawn from the treatment in the IP-treated group, and two in the PL-treated group for gastrointestinal disturbances. In the other women, the tolerance of the drug was good and the complicance with the oral treatment was excellent.     

The effect of calcium supplementation and tanner stage on bone density,content and area in teenage women

One hundred and twelve Caucasian girls, 11.9±0.5 years of age at entry, were randomized into a 24-month, double-masked, placebo-controlled trial to determine the effect of calcium supplementation on bone mineral content, bone area and bone density. Supplementation was 500 mg calcium as calcium citrate malate (CCM) per day. Controls received placebo pills, and compliance of both groups averaged 72%. Bone mineral content, bone mineral area and bone mineral density of the lumbar spine and total body were measured by dual energy X-ray absorptiometry (DXA). Calcium intake from dietary sources averaged 983 mg/day for the entire study group. The supplemented group received, on average, an additional 360 mg calcium/day from CCM. At baseline and after 24 months, the two groups did not differ with respect to anthropometric measurements, urinary reproductive hormone levels or any measurement of pubertal progression. The supplemented group had greater increases of total body bone measures: content 39.9% versus 35.7% (p=0.01), area 24.2% versus 22.5% (p=0.15) and density 12.2% versus 10.1% (p=0.005). Region-of-interest analyses showed that the supplemented group had greater gains compared with the control group for bone mineral density, content and area. In particular, in the lumbar spine and pelvis, the gains made by the supplemented group were 12%–24% greater than the increases made by the control group. Bone acquisition rates in the two study groups were further compared by subdividing the groups into those with below- or above-median values for Tanner score and dietary calcium intake. In subjects with below-median Tanner scores, bone acquisition was not affected by calcium supplementation or dietary calicum level. However, the calcium supplemented subjects with above-median Tanner had higher bone acqusition rates than the placebo group with above-median Tanner scores. Relative to the placebo group, the supplemented group had increased yearly gains of bone content, area and density which represented about 1.5% of adult female values. Such increases, if held to adult skeletal maturity, could provide protection against future risk of osteoporotic fractures.