Maintenance Of Peak Bone Mass Research Articles

Serum 25-hydroxyvitamin D concentrations and selected diet components in postmenopausal women.

Nutrition and lifestyle factors play an important role in the development and maintenance of peak bone mass and the prevention of bone degradation. The aim of the present study was to assess 25-hydroxy- cholecalciferol [25(OH)D] serum concentration in postmenopausal women during the winter period and the supply of selected components in their diet. The study was conducted on a group of 35 women aged 54&ndash;77, using a question- naire, including a 24-hour recall related to a subject&rsquo;s nutrient consumption. Serum concentrations of 25(OH) D were determined. Body composition was assessed with bioelectrical impedance analysis. Mean 25(OH)D serum concentration was found to be 61.2% of the minimum healthy level, according to the reference values. The supply of vitamin D and calcium covered 36.2% and 56.7% of RDA respectively. Correlation analysis has shown a significant inverse relationship between 25(OH)D serum con- centration and body fat (p < 0.05). The study indicates a decreased serum concentration of 25(OH)D in postmenopausal women during the winter period and a low supply of vitamin D and calcium in their diet. Nutrition education should be introduced to the adult population to prevent bone fractures.

Peak-bone-mass development in young adults: effects of study program related levels of occupational and leisure time physical activity and exercise. A prospective 5-year study.

Young adulthood is characterized by profound life-style changes. This study suggests that reduction of sport or exercise, induced by alteration of the occupational situation, negatively impacts generation/maintenance of peak bone mass. In order to compensate occupational-related reductions of physical activity, workplace exercise programs will be helpful. Only few studies have determined the effect of physical activity or physical exercise on bone mineral density (BMD) in the period of late skeletal maturation, i.e. around peak bone mass. The aim of this article was to determine the long-term effect of different levels of physical activity and exercise directly and indirectly derived by occupation during young adulthood. Sixty-one male and female dental students (DES) and 53 male and female sport students (SPS) 21±2 years old were accompanied over the course (4.8±0.5 years) of their study program. BMD at the lumbar spine (LS), hip, and whole body (WB) were determined using dual-energy X-ray absorptiometry. Parameters of physical activity increased non-significantly in both groups with no relevant differences between the groups. Indices of exercise, however, increased significantly in the SPS group while a significant decrease was assessed for the DES group. Independent of gender, BMD of the SPS increased significantly (p≤0.007) at all skeletal sites (LS, 2.4±3.9%; hip, 1.6±3.5%; WB, 1.8±2.8%) while BMD of the DES remained unchanged at LS (-0.6±4.4%, p=0.432) and WB (0.5±1.9%, p=0.092) but decreased significantly at the hip (-1.9±4.3%, p=0.010). BMD-changes at LS, hip, and WB differ significantly between SPS and DES (p≤0.017). Results remained unchanged after adjusting for baseline BMD-values that differed (p=0.030 to p=0.082) in favor of the SPS group. Changes of exercise levels directly or indirectly caused by occupational factors during young adulthood significantly affected generation and/or maintenance of peak bone mass. Compensatory exercise is thus highly relevant for bone health of young adults.

Contribution of the sclerostin domain-containing protein 1 (SOSTDC1) gene to normal variation of peak bone mineral density in Chinese women and men

A genome-wide linkage analysis in Chinese families revealed a significant quantitative trait loci on chromosome 7p21.1 for femoral neck bone mineral density (BMD) (LOD = 3.68), and a potential candidate gene, sclerostin domain-containing protein 1 (SOSTDC1), is located in this region. SOSTDC1 belongs to a class of bone morphogenetic protein (BMP) antagonists that bind BMPs and regulate their signaling. We therefore genotyped 6 tag single nucleotide polymorphisms (tag-SNPs) in SOSTDC1 gene using allele-specific PCR method and investigated the association between SOSTDC1 gene polymorphisms and peak BMD variation in 401 Chinese female-offspring nuclear families (including 1260 subjects) and 400 Chinese male-offspring nuclear families (including 1215 subjects), respectively. Using both family-based (quantitative transmission disequilibrium test) and population-based (ANOVA) methods of analyses, BMD values were adjusted for age, height and weight. In female-offspring nuclear families, we found a significant within family association between rs16878759 and the lumbar spine peak BMD (P = 0.003) and rs16878759 accounted for 1.4% of the lumbar spine peak BMD variation. Moreover, haplotype CCC (containing rs12699800, rs16878759, and rs17619769) had a significant within family association with the lumbar spine peak BMD (P = 0.001) and accounted for 1.9% of the peak BMD variation at this bone site. However, in the male-offspring nuclear families, we failed to detect any significant association between any SNP or haplotype and peak BMD at any bone site. In conclusion, our results indicate for the first time that the genetic polymorphisms in SOSTDC1 have an effect on attainment and maintenance of peak bone mass in Chinese women.

Bone mineral density in adolescent women using depot medroxyprogesterone acetate.

To present current data on bone mineral density (BMD) in adolescent women using the long-acting contraceptive depot medroxyprogesterone acetate (DMPA) and also to discuss the importance of developing maximal bone mass during adolescence to offset bone demineralization later in life. Research-based articles in the medical literature, review articles, and recommendations from the American Academy of Pediatrics and the National Osteoporosis Foundation. Osteoporosis is a preventable disease that affects millions of Americans, particularly older women. Factors influencing the attainment and maintenance of peak bone mass during childhood and adolescence affect the future risk of fractures. Although longitudinal studies conducted on adolescent women using DMPA are very limited, findings suggest that adolescents are losing bone density during a time of expected bone accretion. Clinicians must consider all the risks and benefits when prescribing contraceptives to adolescents. By themselves, the findings related to BMD and DMPA use by adolescents are not sufficient to limit the use of DMPA as a contraceptive method. However, clinicians must take into account the addition of other modifying factors associated with BMD that may contribute to overall bone loss in adolescent females. More prospective data on the long-term use of DMPA by adolescents are needed to determine DMPA's effect on bone loss and to determine if bone loss is transient in adolescents.

Soy Intake and the Maintenance of Peak Bone Mass in Hong Kong Chinese Women

Our previous study on bone health among premenopausal women showed that bone mass consolidation is attained by the early 30s, and small loss of spinal bone mineral density (SBMD) occurs soon after peak bone mass attainment. Recent interest has been shown in the potential beneficial effects of phytoestrogens on bone health. However, data are lacking, particularly in Asian women. This study aims to investigate the effect of soy isoflavones intake on the maintenance of peak bone mass in a cohort of 132 women aged 30-40 years who were followed up for 3 years. Baseline measurements of SBMD (L2-L4) were obtained using dual-energy X-ray densitometry, and dietary intake of soy foods and other key nutrients, including dietary calcium, were obtained through a quantitative food frequency method. Information on body measurements; physical activity (PA), weight-bearing activity in particular; age of menarche; and number of pregnancies were obtained at baseline. Repeated measurements of SBMD were obtained yearly for a further 3 years with an average follow-up time of 38 months. Analyses were performed on 116 subjects with at least three SBMD measurements (at baseline, 3-year follow-up, and at least one measurement during follow-up). The individual SBMD regression slope was computed for each of the subjects. Soy isoflavones consumption was categorized as quartiles of intake. We observed a significant difference in the SBMD individual regression slopes between women belonging to the fourth and first soy isoflavones intake quartiles. The positive effect of soy isoflavones on SBMD remained after adjusting for age and body size (height, weight, and bone area). Multiple linear regression analysis including the other known covariates (lean body mass, PA, energy adjusted calcium, and follow-up time) showed that soy isoflavones, together with these variables, accounted for 24% of the variances of the SBMD individual regression slope. This longitudinal study shows that soy intake had a significant effect on the maintenance of SBMD in women aged 30-40 years. The effects of phytoestrogens on bone health should be explored further in a population with habitual dietary soy but low calcium intake.

Bone mineral density and its change in white women: estrogen and vitamin D receptor genotypes and their interaction.

Low bone mineral density (BMD) is a major risk factor for development of osteoporosis; increasing evidence suggests that attainment and maintenance of peak bone mass as well as bone turnover and bone loss have strong genetic determinants. We examined the association of BMD levels and their change over a 3-year period, and polymorphisms of the estrogen receptor (ER), vitamin D receptor (VDR), type I collagen, osteonectin, osteopontin, and osteocalcin genes in pre- and perimenopausal women who were part of the Michigan Bone Health Study, a population-based longitudinal study of BMD. Body composition measurements, reproductive hormone profiles, bone-related serum protein measurements, and life-style characteristics were also available on each woman. Based on evaluation of women, ER genotypes (identified by PvuII [n = 253] and XbaI [n = 248]) were significantly predictive of both lumbar spine (p < 0.05) and total body BMD level, but not their change over the 3-year period examined. The VDR BsmI restriction fragment length polymorphism was not associated with baseline BMD, change in BMD over time, or any of the bone-related serum and body composition measurements in the 372 women in whom it was evaluated. Likewise, none of the other polymorphic markers was associated with BMD measurements. However, we identified a significant gene x gene interaction effect (p < 0.05) for the VDR locus and PvuII (p < 0.005) and XbaI (p < 0.05) polymorphisms, which impacted BMD levels. Women who had the (-/-) PvuII ER and bb VDR genotype combination had a very high average BMD, while individuals with the (-/-) PvuII ER and BB VDR genotype had significantly lower BMD levels. This contrast was not explained by differences in serum levels of osteocalcin, parathyroid hormone, 1,25-dihydroxyvitamin D, or 25-dihydroxyvitamin D. These data suggest that genetic variation at the ER locus, singly and in relation to the vitamin D receptor gene, influences attainment and maintenance of peak bone mass in younger women, which in turn may render some individuals more susceptible to osteoporosis than others.

Bone mineral density and biochemical parameters of bone turnover in children with growth hormone deficiency.

Growth hormone (GH) is a crucial factor in the build-up and in the maintenance of peak bone mass. Children with GH deficiency have osteopenia and a concomitant reduction in bone turnover. On the other hand, GH therapy improves bone mineral density and stimulates bone turnover. These data suggest that GH treatment may have a beneficial effect on peak bone mass. In children with GH deficiency, the values of some biochemical markers of bone turnover may be closely related to growth response during GH therapy. However, further studies are needed to define the usefulness of bone markers in order to optimize the treatment and to predict the growth outcome in GH-treated children.

Maternal and weanling bone: The influence of lowered calcium intake and maternal dietary history

Skeletal changes in the dam during lactation (a period of skeletal depletion) and the post-lactation period (a time of skeletal repletion) are of interest as a model for the study of mineral metabolism. With the introduction of lowered calcium (Ca) intake during gestation, lactation and the postpartum period, the model can be used to investigate factors that contribute to the development and maintenance of peak bone mass. We have employed this model in the rat with varied calcium intake during gestation, lactation and neonatal growth. In one experiment, dams were maintained on 0.02% Ca during gestation-lactation; at the end of lactation vertebral bone showed decreased bone area, increased osteoid surface and increased osteoblast numbers compared with controls. Trabeculae showed woven bone and diffuse tetracycline label. Offspring from these dams maintained on 0.02% Ca post-weaning weighed less and incurred spontaneous fractures and mortality. In the second experiment dams maintained on 0.5% Ca showed a bone mineral depletion (by single photon densitometry) on days 6 and 19 of lactation, which did not resolve until 28 days post-weaning. Control dams on 1.0% Ca showed no statistically significant depletion nor post-weaning repletion. The third study examined bone mineral content of pups born to 0.5% or 1% Ca-intake dams. Offspring from 0.5% dams retained a bone mineral content deficit despite being fed 1% Ca post-weaning. Offspring from 1% dams placed on 0.5% Ca post-weaning also showed a mineral deficit. Offspring data point to the influence of maternal Ca intake during gestation/lactation. Maternal data point to the import of adequate dietary Ca to maintain the dam's bone quality and quantity during the reproductive and post-reproductive periods.

Perimenopausal bone mass and risk factors

We studied the effect of menopausal status and risk factors on lumbar bone mineral densisty (BMD) and metacarpal cortical thickness (MCT) in 286 women of 46–55 years of age. Body mass index (height/ weight 2) was measured and the family history of osteoporosis, reproductive history, menopausal status, calcium intake, amount of physical activity and the consumption of tobacco and alcohol were assessed. Lumbar BMD and MCT decreased substantially in the perimenopausal and postmenopausal period. In the premenopausal women a significant ( P = 0.03) lower lumbar BMD was observed in the lowest fertile of calcium intake (⩽900 mg/day) compared to the highest tertile (⩾1200 mg/day). This difference was not apparent in the peri- and postmenopausal women. This suggests that dietary calcium intake is more important in the development and/or maintenance of peak bone mass, than in the modulation of postmenopausal bone loss. Apart from menopausal status and low calcium intake, no other significant determinant of bone mass could be identified. We conclude, therefore, that the assessment of risk factor status is not an efficient tool for the identification of perimenopausal women with low bone mass.