Determinants Of Peak Bone Mass Research Articles

Screening for Bone Mineral Density and Assessment Knowledge Level of Low Peak Bone Risk Factors and Preventive Practices Among Kuwaiti Future Mothers.

BackgroundAttaining greater peak bone mass (PBM) prior to the onset of bone loss is getting increasing public health attention as healthy strong bones are essential to maintain our life. Females are more susceptible to bone loss. Knowledge and awareness about low peak bone mass and its related risk factors are important contributors to its preventive behavior.ObjectiveTo screen apparently healthy young Kuwaiti future mothers for low bone mineral density (BMD) and to assess their knowledge level about determinants of PBM and preventive practices.MethodsA cross-sectional comparative study on 445 eligible women aged 18–35 years (either students or employees from Kuwait University) was performed. Data on socio-demographic and lifestyle variables were obtained by a semi-structured questionnaire. Their knowledge was assessed using the modified Osteoporosis Knowledge Assessment Tool (OKAT). Bone mineral Density (BMD) was measured using Quantitative Ultrasonography (QUS).ResultsMore than half (59.3%) of females had poor knowledge. A statistically significant relation was noted between the overall knowledge score and age, college, occupation, and socioeconomic class (P<0.05 for each). Only 13.9% have low Z-score by QUS. By logistic regression, less carbonated beverages and coffee consumption positively affect BMD, while inadequate exercises level, indoor exposure to sunlight, and less frequency of brisk walking negatively affect BMD.ConclusionUnacceptable knowledge score significantly associated with BMD Z-score status. More attention should be devoted to education programs targeting adolescents and young females to promote knowledge about PBM and practice towards accrual and maintenance of bone health.

The Determinants of Peak Bone Mass

The Determinants of Peak Bone Mass

Body fat in children does not adversely influence bone development: a 7‐year longitudinal study (EarlyBird 18)

Both negative and positive associations have been reported between body fat and bone density. Extra mechanical loading from excess fat may lead to greater bone mass. Excess ectopic fat may lead to bone demineralisation through inflammatory pathways. Longitudinally collected data from narrow-angle beam densitometry gives a novel insight into bone growth through adolescence. There is no evidence of a deleterious effect of body fat on children's growing bones after adjustment for height and age. Body fat, mediated by puberty, is associated with larger bones in boys and bones that are both denser and larger in girls. Bone growth is an important determinant of peak bone mass and fracture risk, but there is limited data on the impact of fat-on-bone development at a time when childhood obesity is reaching epidemic proportions. Accordingly, we explored the effect of body fat (BF) on bone growth over time in the context of age, pubertal tempo and gender. A cohort of 307 children was measured biannually from 9-16 years for height and weight, and every 12 months for percent BF, bone area (BA), bone mineral content and areal bone mineral density (aBMD) by dual-energy X-ray absorptiometry. Pubertal tempo was determined quantitatively by age at peak height velocity. Percent BF increased and then fell in the boys, but increased throughout in the girls. aBMD and BA increased in both genders (P < 0.001). Greater BF was associated with higher aBMD and BA in girls (P < 0.001), but only BA in boys (P < 0.001). The extra aBMD associated with increased BF was greater in older girls. The rise in aBMD and BA was associated with earlier puberty in both genders (P < 0.001). The impact of BF on aBMD was greater in later puberty in girls (0.0025 g cm(-2) per 10% BF at 10 years versus 0.016 g cm(-2) per 10% BF at 14 years, P < 0.001). Greater BF is associated with larger bones, but also denser bones in girls. The effects of fat and puberty are complex and gender specific, but BF of contemporary UK children does not appear to be deleterious to bone quality.

Endochondral bone growth, bone calcium accretion, and bone mineral density: how are they related?

Endochondral bone growth in young growing mammals or adult mammals with persistent growth plates progresses from proliferation, maturation and hypertrophy of growth plate chondrocytes to mineralization of cartilaginous matrix to form an osseous tissue. This complex process is tightly regulated by a number of factors with different impacts, such as genetics, endocrine/paracrine factors [e.g., PTHrP, 1,25(OH)(2)D(3), IGF-1, FGFs, and prolactin], and nutritional status (e.g., dietary calcium and vitamin D). Despite a strong link between growth plate function and elongation of the long bone, little is known whether endochondral bone growth indeed determines bone calcium accretion, bone mineral density (BMD), and/or peak bone mass. Since the process ends with cartilaginous matrix calcification, an increase in endochondral bone growth typically leads to more calcium accretion in the primary spongiosa and thus higher BMD. However, in lactating rats with enhanced trabecular bone resorption, bone elongation is inversely correlated with BMD. Although BMD can be increased by factors that enhance endochondral bone growth, the endochondral bone growth itself is unlikely to be an important determinant of peak bone mass since it is strongly determined by genetics. Therefore, endochondral bone growth and bone elongation are associated with calcium accretion only in a particular subregion of the long bone, but do not necessarily predict BMD and peak bone mass.

Bone Mineral Density and Nutritional Status of Healthy Sri Lankan PreSchool Children

: Background: We wished to assess bone mineral density (BMD) values and factors that contribute to bone mineral accrual among preschool children in Sri Lanka. Currently, this information is not available.Objectives: To measure BMDs of spine and hip, using a central-type DXA, in a representative sample of preschool children in Southern Sri Lanka and to study their anthropometry and micronutrient status in order to study the associations of such measurements with bone mineral status.Patients and Methods: We measured BMD of the spine and hip using dual-energy absorptiometry in 105 preschool children (52 boys) aged 3–5 years in Southern Sri Lanka. We also studied their anthropometric characteristics and micronutrient status (iron, zinc, calcium, ceruloplasmin, free thyroxine, and vitamins A and D).Results: Although spine BMD showed no sex difference (mean BMD 0.451 g/cm2 and 0.447 g/cm2 in boys and girls, respectively; p = 0.70), proximal femur BMD values were significantly higher (p = 0.02) among boys (0.594 g/cm2) than among girls (0.557 g/cm2). Boys had significantly higher bone area in the spine, compared to girls (mean 25.58 vs. 24.05 cm2; p = 0.02). After controlling for other independent variables studied (anthropometry and biochemistry), weight and serum calcium accounted for 26% of the BMD variation (R2 = 0.26). One unit change in body weight (1 kg) or serum calcium level (1 mmol/L) was associated with a change in spine BMD of 0.051 g/cm2 or 0.016 g/cm2, respectively.Conclusions: In addition to higher BMD in the proximal femur boys have broader bones, particularly in the spine. Among different indices of body measurements and multiple nutritional factors, body weight and serum calcium appear to be the main determinants of BMD accrual. Implication for health policy/practice/research/medical education:Study on determinants of childhood bone mineral accrual would identify the major determinant of peak bone mass in later life. Please cite this paper as: Hettiarachchi M, Lekamwasam S, Liyanage C. Bone Mineral Density and Nutritional Status of Healthy Sri Lankan Preschool Children. Int J Endocriol Metab.2011;9(2):335-40. DOI: 10.5812/kowsar.1726913X.2385 Copyright © 2012, Kowsar M.P.Co. All rights reserved.

Peak bone mass from longitudinal data: implications for the prevalence, pathophysiology, and diagnosis of osteoporosis.

We estimated peak bone mass (PBM) in 615 women and 527 men aged 16 to 40 years using longitudinal data from the Canadian Multicentre Osteoporosis Study (CaMos). Individual rates of change were averaged to find the mean rate of change for each baseline age. The age range for PBM was defined as the period during which bone mineral density (BMD) was stable. PBM was estimated via hierarchical models, weighted according to 2006 Canadian Census data. Lumbar spine PBM (1.046 ± 0.123 g/cm(2)) occurred at ages 33 to 40 years in women and at 19 to 33 years in men (1.066 ± 0.129 g/cm(2)). Total hip PBM (0.981 ± 0.122 g/cm(2)) occurred at ages 16 to 19 years in women and 19 to 21 years in men (1.093 ± 0.169 g/cm(2)). Analysis of Canadian geographic variation revealed that the levels of PBM and of mean BMD in those over age 65 sometimes were discordant, suggesting that PBM and subsequent rates of bone loss may be subject to different genetic and/or environmental influences. Based on our longitudinally estimated PBM values, the estimated Canadian prevalences of osteoporosis (T-score < -2.5) were 12.0% (L(1)-L(4)) and 9.1% (total hip) in women aged 50 years and older and 2.9% (L(1)-L(4)) and 0.9% (total hip) in men aged 50 years and older. These were higher than prevalences using cross-sectional PBM data. In summary, we found that the age at which PBM is achieved varies by sex and skeletal site, and different reference values for PBM lead to different estimates of the prevalence of osteoporosis. Furthermore, lack of concordance of PBM and BMD over age 65 suggests different determinants of PBM and subsequent bone loss.

Perception of risk factors and DXA T score among at‐risk females of osteoporosis

This paper reports a study to investigate the relationships among bone mineral density, demographics, knowledge of osteoporosis, beliefs concerning osteoporosis and preventive behaviours of at-risk females with family histories of osteoporosis. Strong evidence demonstrates that genetics is a significant determinant of peak bone mass, with a heritability of 50-90%. However, few studies have examined the bone mineral density of at-risk females with family histories of osteoporosis, particularly in an Asian population. Telephone survey. The study population (n=2890) was recruited from a radiology department at a national university medical centre in northern Taiwan during 2005-2006. In total, 886 females completed a questionnaire via the telephone; the participation rate was 30·7%. The bone mineral density of at-risk females was close to osteopenia status (T score of -1 to -2·49). Most subjects were aware of osteoporosis-related information; however, few clearly understood osteoporosis. Furthermore, subjects reported difficult implementing strategies to improve bone mineral density. Variation in bone mineral density was correlated with self-rated health (r=0·56, p<0·05), knowledge of osteoporosis (r=0·66, p<0·05) and preventive behaviours (r=0·68, p<0·05). This study is to examine risk factors associated with bone mineral density of females with family histories of osteoporosis. Early identification of risk factors for osteoporosis and development of prevention programmes are required to halt the increasing in the incidence of osteoporosis and improve the bone mineral density of at-risk females. Nursing care professionals, who emphasise primary, secondary and tertiary prevention with individuals and families, should develop effective prevention strategies for women with family the history of osteoporosis to protect the health of these vulnerable populations at-risk for osteoporosis.

Determinants of peak bone mass and bone mineralization rates in 470 healthy children, adolescents and young adults: A prospective study

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Serum Estradiol Is Associated With Volumetric BMD and Modulates the Impact of Physical Activity on Bone Size at the Age of Peak Bone Mass: A Study in Healthy Male Siblings

This study investigates determinants of peak bone mass (PBM) in healthy men, focusing on effects and interactions of parameters reflecting mechanical loading and sex steroids. Healthy male siblings (n = 677; 25-45 yr) were recruited in a cross-sectional, population-based study. Physical activity score was assessed by a self-reported questionnaire. Cross-sectional muscle area (CSMA) and bone parameters of radius (4% and 66% site) and tibia (66% site) were assessed using pQCT. Peak torque of biceps and quadriceps muscles was assessed by isokinetic dynamometry. Serum testosterone (T) and estradiol (E(2)) levels were measured using immunoassays; free hormone fractions were calculated. Relations between indices of bone strength, CSMA, muscle strength, and sex steroids were studied using linear mixed-effects modeling. Physical activity, CSMA, and muscle strength were positively associated with indices of bone strength, except for volumetric BMD (vBMD). After controlling for age, weight, and height, free E(2) levels were positively associated with trabecular and cortical vBMD, negatively associated with endosteal circumference at the radius, and positively associated with cortical vBMD at the tibia. In addition, positive interactions between physical activity and serum E(2) concentrations were observed for bone size at the tibia. No associations between free T levels and pQCT bone parameters were found. In this population of healthy men at the age of PBM, parameters reflecting mechanical loading are confirmed as important determinants of bone size. E(2), but not T, levels are positively associated with vBMD and modulate the impact of physical activity on bone size at the tibia.

Fetal and postnatal bone development: reviewing the role of mechanical stimuli and nutrition

Fetal and postnatal bone development is by tradition viewed as a process of bone mineral accretion or an increase in bone mass. Accordingly, previous approaches to bone development in neonatology and early childhood have emphasized the determinants of peak bone mass and their relationship to osteopenia, osteoporosis and fractures in later life. This suggests that the neonatal period and early childhood is an important period for bone mineral accrual, and that peak bone mass may be correlated with subsequent skeletal health. Nevertheless, describing fetal and postnatal bone development just in terms of changes in mass or density means looking at bones as if they were amorphous heaps of calcium and phosphorus. In reality, of course, bones are complex three-dimensional structures. It is therefore important to create conditions that stimulate bones to become more stable. We suggest that functional bone physiology can be used to explain fetal and postnatal bone development and to devise strategies for improved bone development in both premature infants and neonates.

Gender Differences in Bone Mineral Density in Epilepsy

Bone accrual in adolescence is a major determinant of peak bone mass and risk of osteoporotic fractures later in life. Postmenopausal women are at highest risk, although, both men and premenopausal women with epilepsy experience adverse bone effects. We examined gender differences in bone density in epilepsy. Cross-sectional study examining age and gender-specific z-score total bone mineral density (z-BMD) in 108 ambulatory children with epilepsy between 6 and 18 years of age (61 females 12.8 +/- 3.6 years; 47 males 12.4 +/- 3.1 years) compared to 35 healthy controls who were first-degree cousins of patients (21 females 13.8 +/- 2.5 years and 14 males 11.7 +/- 2.5 years). Patients with epilepsy accrued lower z-BMD compared to controls (0.27 +/- 0.77 vs. 0.53 +/- 1.1, p < 0.05), and were reduced for both females (0.23 +/- 1.1 vs. 0.47 +/- 0.76; p = 0.14, NS) and males (0.3 +/- 1.1 vs. 0.8 +/- 0.5; p = 0.11, NS). Increasing duration of epilepsy was associated with lower BMD in males (correlation coefficient = 0.06; p = 0.05). Males with > or =6 years of epilepsy experienced the lowest z-BMD compared to controls (-0.89 +/- 0.80 vs. 0.62 +/- 0.80; p = 0.45). Fractures occurred in two females with epilepsy for > or =6 years and z-BMD of -1.5 and -2.7. BMD in both males and females with epilepsy is reduced. Young males with more chronic epilepsy (> or =6 years) had the lowest BMD. Age at onset of epilepsy, growth trends, and hormonal differences may underlie these gender differences. Lower bone accrual in adolescence may contribute to increased fracture risk for both men and women with epilepsy.

Determinants of peak bone mineral density and bone area in young women

Osteoporosis is a disease caused by compromised bone strength, and individuals with a high peak bone mass at a young age are likely to have a high bone mass in old age. To identify the clinical determinants of peak bone mass in young adult women, 418 southern Chinese women, aged 20-39 years, were studied. Low bone mass was defined as areal bone mineral density (aBMD) Z-score < -1 at either the spine or total hip. Within the cohort, 62 (19.0%) and 86 (26.4%) women had low aBMD at the spine and hip, respectively. Regression model analysis revealed that low body weight (<44 kg) was associated with an 8.3-fold (95% CI, 3.7-18.9) and a 6.8-fold (95% CI, 3.0-15.6) risk of having low aBMD at the spine and hip, respectively. Low body weight was also predictive of low volumetric BMD (vBMD) at the spine (odds ratio (OR) 7.8, 95% CI, 3.1-20.1) and femoral neck (OR 3.0, 95% CI, 1.3-7.1). A body height below 153 cm was associated with a 4.8-fold risk in the small L2-4 bone area (95% CI, 2.3-9.8) and a 3.9-fold risk in the small femoral neck area (95% CI, 1.9-8.1). Delayed puberty (onset of menstruation beyond 14 years) was associated with a 2.2-fold (95% CI, 1.0-4.9) increased risk of having low aBMD at the hip. Physical inactivity was associated with a 2.8-fold risk of low spine vBMD (OR 2.8, 95% CI, 1.1-6.7) and a 3.3-fold risk of low hip aBMD (95% CI, 1.0-10.0). Pregnancy protected against low spine aBMD (OR 0.4, 95% CI, 0.1-1.2) and spine vBMD (OR 0.1, 95% CI, 0.0-1.0), low femoral neck vBMD (OR 0.3, 95% CI, 0.1-1.1) and small L2-4 bone area vBMD (OR 0.3, 95% CI, 0.1-1.1). In conclusion, this study identified a number of modifiable determinants of low peak bone mass in young adult women. Maintaining an ideal body weight, engaging in an active lifestyle, and diagnosing late menarche may enable young women to maximize their peak bone mass and so reduce their risk of osteoporosis in later life.

Genetic and environmental influences on bone mineral density in pre- and post-menopausal women

Genetic factors influencing acquisition of peak bone mass account for a substantial proportion of the variation in bone mineral density (BMD), although the extent to which genes also contribute to variation in bone loss is debatable. Few prospective studies of related individuals have been carried out to address this issue. To gain insights into the nature of the genetic factors contributing to variation in BMD, we studied 570 women from large Amish families. We evaluated and compared the genetic contributions to BMD in pre- and post-menopausal women, with the rationale that genetic variation in pre-menopausal women is due primarily to genetic determinants of peak bone mass, while genetic variation in post-menopausal women is due to the combined genetic effects of peak bone mass and bone loss. Bone mineral density was measured at one point in time at the hip and spine by dual energy X-ray absorptiometry (DXA). We used variance decomposition procedures to partition variation in BMD into genetic and environmental effects common to both groups and to pre- and post-menopausal women separately. Total variation in BMD was higher in post- compared to pre-menopausal women. Genes accounted for 58-88% of the total variation in BMD in pre-menopausal women compared to 37-54% of the total variation in post-menopausal women. In absolute terms, however, the genetic variance was approximately similar between the two groups because the environmental variance was 3 1/2- to 4-fold larger in the post-menopausal group. The genetic correlation in total hip BMD was 0.81 between pre- and post-menopausal women and differed significantly from one, consistent with the presence of at least some non-overlapping genetic effects in the two groups for BMD at this site. Overall, these analyses suggest that many, but not all, of the genetic factors influencing variation in BMD are common to both pre- and post-menopausal women.

The relation of the Xbal and Pvull polymorphisms of the estrogen receptor gene and the CAG repeat polymorphism of the androgen receptor gene to peak bone mass and bone turnover rate among young healthy men

The genes coding for estrogen receptor-alpha (ER-alpha) and androgen receptors (AR) are potential candidates for the regulation of bone mass and turnover, which may contribute to both the achievement of peak bone mass and bone loss after completion of growth. The present study was aimed at elucidating the role of two restriction fragment lengths (XbaI and PvuII) polymorphisms of the ER gene and the CAG repeat polymorphism of the AR gene as determinants of peak bone mass in men; special attention was paid to the interaction between serum free estradiol (E2) levels and the XbaI and PvuII genotypes. A cross-sectional study, with data on lifestyle factors collected retrospectively, was performed in 234 young men, aged 18.3 to 20.6 years. Of the men, 184 were recruits of the Finnish Army and 50 were men of similar age who had postponed their military service for reasons not related to health. Bone mineral content (BMC), density (BMD) and scan area were measured in the lumbar spine and upper femur by dual-energy X-ray absorptiometry (DXA). The bone turnover rate was assessed by measuring serum type I procollagen aminoterminal propeptide (PINP) and tartrate-resistant acid phosphatase 5b (TRACP5b) as well as urinary excretion of type I collagen aminoterminal telopeptide (NTX). After adjusting for age, height, weight, exercise, smoking, calcium and alcohol intake, BMC, scan area and BMD at all measurement sites were similar for the different XbaI and PvuII genotypes of the ER and independent of the number of the CAG repeats of the AR gene. No association was found between free E2 levels and bone parameters among any genotype group of the XbaI and PvuII polymorphisms. Except for urinary NTX, which showed a tendency to higher values for the xx (P=0.08) and pp (P=0.10) genotypes of the ER, bone turnover markers were not related to the genotypes studied. Our study does not support the view that the XbaI and PvuII polymorphisms of the ER gene and the CAG polymorphism of the AR gene would have a substantial impact on the development of peak bone mass in young Finnish men.

Serum estradiol, testosterone, and sex hormone-binding globulin as regulators of peak bone mass and bone turnover rate in young Finnish men.

To study the role of serum testosterone (T), estradiol (E(2)), and SHBG as regulators of peak bone mass and bone turnover rate in males, a cross-sectional study with data on lifestyle factors collected retrospectively was performed in 204 young Finnish men, 18.3-20.6 yr old. One hundred fifty-four men were recruits of the Finnish Army, and 50 were men of similar age who had postponed their military service for reasons not related to health. Bone mineral content, density, and scan area were measured in lumbar spine and upper femur by dual-energy x-ray absorptiometry. Blood was sampled for determination of serum total and free T, total and free E(2), SHBG, type I procollagen aminoterminal propeptide (PINP), total osteocalcin (TOC) and carboxylated osteocalcin (COC), and tartrate-resistant acid phosphatase 5b (TRACP5b); and urine was collected for determination of type I collagen aminoterminal telopeptide (NTX). Serum sex steroid concentrations did not associate with bone mineral content, scan area, or bone mineral density, adjusted for anthropometric and lifestyle factors at any measurement site. Instead, serum total (r = 0.23; P = 0.008) and free (r = 0.15; P = 0.023) T were positive predictors of serum TOC, whereas serum free E(2) correlated inversely with serum PINP (r = -0.20; P = 0.0039), TOC (r = -0.12; P = 0.086), COC (r = -0.14; P = 0.036), and urinary NTX (r = -0.15; P = 0.041). Interestingly, serum SHBG correlated positively with all the bone markers studied, the correlation coefficients being 0.18 for serum PINP (P = 0.012), 0.24 for TOC (P = 0.0006), 0.24 for COC (P = 0.0005), 0.27 for serum TRACP5b (P < 0.0001), and 0.21 for urine NTX (P = 0.0031). Serum SHBG was also a positive predictor of serum 25-hydroxyvitamin-D level (r = 0.20; P = 0.0036). The correlations of SHBG persisted after adjusting for weight, free E(2), and free T. We conclude that single measurements of serum E(2) and T were not determinants of peak bone mass in this population of young men. However, E(2) and T contributed to bone turnover rate, with serum T increasing bone formation, and serum E(2) suppressing both bone formation and resorption. Moreover, serum SHBG appeared to be an independent positive predictor of bone turnover rate, which also positively associated with serum 25-hydroxyvitamin-D levels.

Early milk intake, later bone health: results from using the milk history questionnaire.

Milk intake is considered an important determinant of peak bone mass; consequently, its intake early in life may decrease risk of osteoporotic fractures later. Using the milk history questionnaire, many investigators have conducted retrospective cross-sectional studies and have determined a positive effect of milk intake in childhood and adolescence on bone mineral density in adult white women. By contrast, a recent study indicates that early milk intake has no beneficial effect on bone mineral density in black women. The milk history questionnaire can assist in determining diet-bone relationships in various groups.

To What Extent Is Bone Mineral Density Determined By Body Composition In Brazilian Postmenopausal Women?

2051 Previous study of the relative importance of fat mass (FM) and Fat Free Mass (FFM) as a determinant of bone mineral density (BMD) have yielded discordant results. Additionally, Aloia et al. (1995) reported that bone mass may be partially influenced by race. PURPOSE: The aim of this study was to determine to what extent bone mineral density (BMD) is determined by body mass (BM), FM, and FFM in healthy Brazilian postmenopausal women. METHODS: Total body composition and regional bone mass were measured in 97 sedentary, healthy postmenopausal women recruited from the general community. The mean age was 66.41 ± 4.82 years, range 60–79. Total body composition (fat and lean tissue) and regional bone density in the lumbar spine and femur were measured by dual energy X-ray absorptiometry (DXA) on a Lunar DPX-IQ. The participants were screened for medical conditions that may alter BMD, and were excluded from the study if they had been on hormone-replacement therapy (HRT). Contraindications also included: cigarette smoking and alcohol abuse. The relationship of BM, FM and FFM with BMD were first generated separately using linear regression (bivariate). Multiple linear regression then was used to determine the relative contribution of BM, FM and FFM to the variance in BMD. RESULTS: Total BM was more strongly correlated with femur and lumbar spine BMD (r = 0.54 and 0.37, respectively) than FM (r = 0.30 and 0.19) and FFM (r = 0.44 and 0.26). CONCLUSION: Both fat and lean tissue mass are related to femur bone mass in postmenopausal women, however the relationship being strongest for body weight. FM shows weaker correlations for both femur and lumbar BMD. In view of the direction and magnitude of changes in body composition and bone mineral after the menopause, body weight and muscularity are more likely to be determinants of peak bone mass of postmenopausal Brazilian women.

To What Extent Is Bone Mineral Density Determined By Body Composition In Brazilian Postmenopausal Women?

2051 Previous study of the relative importance of fat mass (FM) and Fat Free Mass (FFM) as a determinant of bone mineral density (BMD) have yielded discordant results. Additionally, Aloia et al. (1995) reported that bone mass may be partially influenced by race. PURPOSE: The aim of this study was to determine to what extent bone mineral density (BMD) is determined by body mass (BM), FM, and FFM in healthy Brazilian postmenopausal women. METHODS: Total body composition and regional bone mass were measured in 97 sedentary, healthy postmenopausal women recruited from the general community. The mean age was 66.41 ± 4.82 years, range 60–79. Total body composition (fat and lean tissue) and regional bone density in the lumbar spine and femur were measured by dual energy X-ray absorptiometry (DXA) on a Lunar DPX-IQ. The participants were screened for medical conditions that may alter BMD, and were excluded from the study if they had been on hormone-replacement therapy (HRT). Contraindications also included: cigarette smoking and alcohol abuse. The relationship of BM, FM and FFM with BMD were first generated separately using linear regression (bivariate). Multiple linear regression then was used to determine the relative contribution of BM, FM and FFM to the variance in BMD. RESULTS: Total BM was more strongly correlated with femur and lumbar spine BMD (r = 0.54 and 0.37, respectively) than FM (r = 0.30 and 0.19) and FFM (r = 0.44 and 0.26). CONCLUSION: Both fat and lean tissue mass are related to femur bone mass in postmenopausal women, however the relationship being strongest for body weight. FM shows weaker correlations for both femur and lumbar BMD. In view of the direction and magnitude of changes in body composition and bone mineral after the menopause, body weight and muscularity are more likely to be determinants of peak bone mass of postmenopausal Brazilian women.

Bone Densitometry in Premenopausal Women: Synthesis and Review

Abstract Bone loss prior to menopause is being increasingly identified in women. Clearly, low bone mineral density (BMD) is a significant risk factor for fracture in the estrogen-deficient female postmenopause. The significance of low bone density prior to menopause needs to be addressed. Low bone density in the premenopausal female may reflect attainment of a lower peak bone mass. It may also be secondary to progressive bone loss following achievement of peak bone density. The etiology of low bone density in the premenopausal female needs to be clarified with meticulous exclusion of secondary causes of bone loss. Menstrual status is an important determinant of peak bone mass as well as the development of bone loss in women prior to the onset of menopause. Subclinical decreases in circulating gonadal steroids may be associated with a lower peak bone mass as well as progressive bone loss in otherwise reproductively normal women. Elevations of follicle-stimulating hormone (FSH) of greater than 20 miu/L are associated with evidence of increased bone turnover marker activity and correlate with progressive bone loss in perimenopausal women. This transitional period requires further study with respect to the magnitude of bone loss experienced and the potential benefits of antiresorptive therapy. Detailed assessment of menstrual status is necessary in the evaluation of low bone density in premenopausal women. The majority of the cross-sectional and longitudinal studies completed evaluating BMD in the premenopausal years suggest that minimal bone loss does occur prior to menopause after attainment of peak bone mass. The magnitude of premenopausal bone loss, however, is controversial and may be site-dependent. More rapid rates of bone loss are seen in the transitional period beginning 2–3 yr prior to the onset of menopause. Prospective data are needed to understand further the relationship between BMD and fracture in the premenopausal period. Women with steroid-induced bone loss as well as other secondary causes of osteoporosis respond to antiresorptive therapy with documented improvements in BMD. Biomarkers can identify perimenopausal women with increased bone turnover. Lifestyle modification can improve BMD in the pre- and the perimenopausal period. Antiresorptive therapy has not been evaluated in pre- or perimenopausal women with low BMD in the absence of secondary causes of osteoporosis. As new treatment options are evaluated and become available, biomarker assessment may be of value in identifying women at risk of fracture. This paper provides a review of the literature and recommendations with respect to management of low bone density in the premenopausal female.

Vitamin D status as a determinant of peak bone mass in young Finnish men.

Severe vitamin D deficiency causes rickets, but scarce data are available about the extent to which vitamin D status determines the development of the peak bone mass in young adults. Our aim was to evaluate the prevalence of vitamin D deficiency [serum 25-hydroxyvitamin D (25-OHD) less than the lower limit of the reference range of 20-105 nmol/liter] and the relationship between vitamin D status and peak bone mass among young Finnish men. A cross-sectional study of determinants of peak bone mass with data on lifestyle factors collected retrospectively was performed in 220 young men, aged 18.3-20.6 yr. One hundred and seventy men were recruits of the Finnish Army, and 50 were men of similar age who had postponed their military service for reasons not related to health. Bone mineral content, bone mineral density, and scan area were measured in lumbar spine and upper femur by dual energy x-ray absorptiometry. Serum 25-OHD concentrations were followed prospectively for 1 yr. In July 2000, only 0.9% of the men had vitamin D deficiency, but 6 months later, in the winter, the respective percentage was 38.9%. After adjusting for age, height, weight, exercise, smoking, calcium, and alcohol intake, there existed a positive correlation between serum 25-OHD and bone mineral content at lumbar spine (P = 0.057), femoral neck (P = 0.041), trochanter (P = 0.010), and total hip (P = 0.025). The correlation coefficients for the bone mineral densities at the four measurement sites were 0.035, 0.061, 0.056, and 0.068, respectively. No correlation was found to scan area. We conclude that vitamin D deficiency is very common in Finnish young men in the winter, and it may have detrimental effects on the acquisition of maximal peak bone mass. As in Finland vitamin D supplementation to infants is now stopped at the age of 3 yr, it can be asked whether at our latitude it should be continued from that age onward, not for the prevention of rickets, but as prophylaxis for osteoporosis.