Bone Mass In Young Women Research Articles

Proposal for targeted, neo-evolutionary-oriented secondary prevention of early-onset endometriosis and adenomyosis. Part II: medical interventions.

According to consistent epidemiological data, the slope of the incidence curve of endometriosis rises rapidly and sharply around the age of 25 years. The delay in diagnosis is generally reported to be between 5 and 8 years in adult women, but it appears to be over 10 years in adolescents. If this is true, the actual onset of endometriosis in many young women would be chronologically placed in the early postmenarchal years. Ovulation and menstruation are inflammatory events that, when occurring repeatedly for years, may theoretically favour the early development of endometriosis and adenomyosis. Moreover, repeated acute dysmenorrhoea episodes after menarche may not only be an indicator of ensuing endometriosis or adenomyosis, but may also promote the transition from acute to chronic pelvic pain through central sensitization mechanisms, as well as the onset of chronic overlapping pain conditions. Therefore, secondary prevention aimed at reducing suffering, limiting lesion progression, and preserving future reproductive potential should be focused on the age group that could benefit most from the intervention, i.e. severely symptomatic adolescents. Early-onset endometriosis and adenomyosis should be promptly suspected even when physical and ultrasound findings are negative, and long-term ovulatory suppression may be established until conception seeking. As nowadays this could mean using hormonal therapies for several years, drug safety evaluation is crucial. In adolescents without recognized major contraindications to oestrogens, the use of very low-dose combined oral contraceptives is associated with a marginal increase in the individual absolute risk of thromboembolic events. Oral contraceptives containing oestradiol instead of ethinyl oestradiol may further limit such risk. Oral, subcutaneous, and intramuscular progestogens do not increase the thromboembolic risk, but may interfere with attainment of peak bone mass in young women. Levonorgestrel-releasing intra-uterine devices may be a safe alternative for adolescents, as amenorrhoea is frequently induced without suppression of the ovarian activity. With regard to oncological risk, the net effect of long-term oestrogen-progestogen combinations use is a small reduction in overall cancer risk. Whether surgery should be considered the first-line approach in young women with chronic pelvic pain symptoms seems questionable. Especially when large endometriomas or infiltrating lesions are not detected at pelvic imaging, laparoscopy should be reserved to adolescents who refuse hormonal treatments or in whom first-line medications are not effective, not tolerated, or contraindicated. Diagnostic and therapeutic algorithms, including self-reported outcome measures, for young individuals with a clinical suspicion of early-onset endometriosis or adenomyosis are proposed.

Relationship between vitamin D receptor gene polymorphisms (BsmI, TaqI, ApaI, and FokI) and calcium intake on bone mass in young Japanese women

BackgroundThe high prevalence of low bone mass in young women in Japan has emerged as a serious health issue in recent years. Therefore, the aim of the present study was to reevaluate the relationship between genetic and dietary factors, as well as its influence on bone mass in young Japanese women, with particular emphasis on vitamin D receptor (VDR) gene polymorphisms and calcium intake.MethodsA total of 499 Japanese women aged 20–24 years were enrolled in the study. The bone mass of the calcaneus was assessed using the quantitative ultrasound method and expressed as the osteo sono-assessment index (OSI). VDR gene polymorphisms (BsmI, TaqI, ApaI, and FokI) were analyzed using DNA extracted from saliva. Calcium intake was assessed using the Food Frequency Questionnaire based on food groups (FFQg) and adjusted with the energy intake. Participants were divided into two groups based on the median calcium intake (250 mg/1000 kcal).ResultsConsequently, bone mass was significantly different among the BsmI and TaqI genotypes after adjusting for body mass index (BMI) (p = 0.030 and 0.019, respectively). In addition, the BsmI AA and ApaI GT genotypes showed significant differences in bone mass between the calcium-intake groups, with low OSI in the low-calcium intake group and high OSI in the high-calcium intake group, respectively, even after adjusting for BMI (p = 0.020 and 0.038, respectively).ConclusionsThese findings may prove instrumental in developing a logical approach towards preventing bone loss in young Japanese women.

Maternal mortality, marital status and bone mineral density in young women from the Coimbra identified skeletal collection.

In contemporary populations, pregnancy and lactation are usually followed by transient bone loss. The observation of reduced bone mass in young females from archaeological sites has sometimes been interpreted as an outcome of reproductive stress. In order to evaluate the overall effect of reproductive dynamics on bone mass in a historical skeletal sample, bone mineral density (BMD) at the proximal femur was assessed by dual-energy X-ray absorptiometry in 78 young women (17-39 years) from the Coimbra Identified Skeletal Collection. BMD was compared within the skeletal sample ("maternal deaths" [ICD - 10: chapter XV] vs. "other causes of death", and "married/widowed women" vs. "single women"). Results revealed that mean BMD differences among groups are non-significant, suggesting that a strict reproductive interpretation of premature bone loss in young women from archaeological contexts is not sustained by empirical evidence. Bone mass in young women from archaeological sites should be interpreted as a complex trait stemming from the interplay between reproductive factors, genetics, nutrition, physical activity, and age at menarche.

Vitamin D receptor and Estrogen receptor alpha Genotype affects Exercise related Bone mass in Japanese healthy women

PURPOSEOsteoporosis is a systemic skeletal disease characterized by low bone mass and/or fragile bone. The vitamin D receptor (VDR) and estrogen receptor alpha (ESR1) are a good genetic candidate for a prime regulator of bone metabolism. The purpose of this study was to assess the interactive effects of exercise, food intake, VDR and/or ESR1 polymorphism on bone mass.METHODS240 healthy young women (20–23 yr) were recruited in this study. Bone mass and body composition were measured. Food frequency and exercise‐related questionnaires were used to estimate calcium intake and exercise intensity. The VDR (rs7975232) and ESR1 (rs2234693) polymorphisms were genotyped using the TaqMan‐based SNP method.RESULTSExercise and milk‐intake were significantly associated with bone mass in the whole subjects. The bone mass in non‐exercised participants with CC homozygote in ESR1 was lower than that in TT homozygote. The bone mass in high‐intensity exercised participants carrying CC heterozygotes in ESR1 and VDR was significantly higher than that in low‐intensity.These results suggest that exercise attenuates are the increase of peak bone mass in young women carrying C allele in VDR and ESR1.Supported by Grants‐in‐Aid for Science Research from the Japanese Ministry of Education, Culture, Sports, Science and Technology.

Effect of Exercise Program and Calcium Supplements on Low Bone Mass among Young Indian Women- A Comparative Study

Low bone mass is a major health concern among young women nowadays due to sedentary lifestyle and lack of calcium rich food intake. Therefore there is an increase in the incidence of LBM among young university women so our main purpose of study was to compare effects of exercise program and calcium supplements on bone mass in young women. This single blinded, cross sectional study included data collection in the form of SOS T-scores at distal radius for 104 young university women of mean age 22.3 years using Sunlight Omnisense Bone Sonometer 7000S. Of these, 62 women with low bone mass were included in a 3 month study but 60 subjects completed the study. They were randomly divided into 3 groups: exercise group (n=21), calcium supplementation group (n=21) and control group (n=20). All participants were evaluated pre and post protocol for T-score distal radius and midshaft tibia. After measuring SOS T-score of 104 subjects; we found that 60.57% had low bone mass and remaining 39.43% had normal bone mass. After 3 months, the exercise group showed significant improvement in distal radius SOS T-score (t=5.10, P<0.001), at midshaft tibia (t=3.71, P<0.001) followed by improvement in calcium group at distal radius (t=6.28, P<0.001), midshaft tibia (t=2.33, P<0.05) as compared to control group which showed a marginal increase. Exercise group showed more improvement in T-scores than calcium and control group. Exercise is important modifiable factor to improve bone accretion at this age and reduce risk of developing osteoporosis related debilitating conditions later in life.

Regular Follow-Up Increases Ground Reaction Forces During a Home-Based Exercise Intervention to Improve Bone Mass in Young Women

Home-based exercises are convenient but do women follow the protocols they are given? PURPOSE: We compared ground reaction forces (GRFs) during a home-based jumping program for subjects receiving periodic follow-up with those who were not. METHODS: 205 women, 102 in cohort 1 (CH1) and 103 in cohort 2 (CH2) (aged 23.4±4.5y) were randomly assigned to one of three box jump height groups (4", 8", 12"). During the pretest visit, correct jumping technique was demonstrated for each subject. All were instructed to perform training at home from their prescribed box height adhering to this technique. CH1 subjects returned for posttest evaluation 9 months later, while CH2 subjects returned for evaluation at 3, 6, and 9 months. GRF evaluation consisted of 10 jumps on a Kistler force platform using the box height and technique practiced at home. Average peak GRF was determined for filtered peaks within each subject's mean ±1SD. RESULTS: Mean GRFs for CH1 and CH2 are shown in Table 1. GRFs for CH1 were not different across box heights, but were different for CH2 subjects using the 4" and 12" box. Subjects in CH2, 8" and 12" groups also achieved higher GRFs than those in CH1.Table 1: GRFs across three jump heightsCONCLUSIONS: We confirm the benefit of periodic follow-up to ensure that desired loads are being applied during home-based training. This has implications for programs to prevent bone loss in women who may unknowingly attenuate prescribed exercise-induced loading by altering kinematics during the landing phase of a box jump. Lab-based studies have shown GRFs of 6 times body weight for drop landings from 12-inches (Yeow et al, 2009), similar to our results at this height in CH2. We confirm that home-based training with follow-up can closely approximate GRFs during lab-based training. (NIH SC3 GM084705)

Effects of Exercise on Bone Mass in Young Women with Anorexia Nervosa

The response of bone to exercise in women with anorexia nervosa (AN) is unclear. We investigated the associations between bone mineral density (BMD) and exercise performed while ill and while recovered in women with a history of AN. A cross-sectional study was conducted with 141 women with AN (85 ill; 56 recovered), aged 17-40 yr. BMD at the lumbar spine (LS), femoral neck (FN), and total body (TB) was measured by dual-energy x-ray absorptiometry. Life History Calendar and Minnesota Leisure Time Physical Activity interviews were used to collect lifetime illness and exercise histories (amount and bone loading type). Average hours per week of each of moderate (MOD) and high (HI) bone loading exercise were determined for three illness phases: "before ill," "while ill," and "while recovered." Participants were categorized into four exercise groups for each phase: MOD-ONLY, HI-ONLY, BOTH, and NEITHER (reference group). Weight-adjusted BMD z-scores were compared in the exercise groups by multivariable linear regression, adjusting for illness duration and severity, and exercise during the other illness phases. In ill participants, MOD-ONLY "while ill" had lower BMD at LS (β = -0.69, 95% confidence interval (CI) = -1.02 to -0.05) and TB (β = -0.73, 95% CI = -1.31 to -0.15) than the NEITHER group. In recovered participants, HI-ONLY "while recovered" had higher BMD at FN (β = 0.95, 95% CI = 0.15-1.75) and TB (β = 0.79, 95% CI = 0.07-1.51) than the NEITHER group. The effect of exercise on bone in AN patients is dependent on both the type of mechanical loading and the phase of illness during which it was performed. Excessive moderate loading exercise while ill may put patients at higher risk of low bone mass, but high bone loading activities may provoke bone accrual during recovery.

Delayed Puberty Results in Decreased Percentage of Lamellar Bone and Decreased Mechanical Strength in Female Rats

The failure to attain peak bone mass during childhood has been linked to bone fracture in adulthood. An increased age at puberty correlates with low bone mass in young women and an increased incidence of stress fracture. A model of delayed puberty has reported deficits in mechanical strength yet increases in the size of the cortex. Furthermore, there were increases in periosteal labeled surface. It is hypothesized that the microarchitecture of the bone differs between the delayed puberty and control animals and results in decreased bone strength in the delayed puberty group. PURPOSE: The goal of this study was to determine the relative amounts of lamellar and non-lamellar bone in the femoral cortex of animals with delayed pubertal onset. METHODS: At 23 days of age, female Sprague Dawley rats (Charles River) were randomly assigned into a control group (n=15) and a delayed puberty group that received injections of Gonadotropin releasing hormone antagonist (GnRH-a) (Zentaris GmbH) intraperitoneally (0.2ml) for a 29 day period (500 ug/dose, 5 days per week). Left femora were mechanically tested under 3-point bending. The right femora were dehydrated, embedded in polymethylmethacrylate, cut and ground to 100 μm thickness. Bones were analyzed under polarized light using Stereo Investigator Software. The proportion of the cortex with primary lamellar versus woven/other primary tissue type were measured and expressed as percent of the total cortical bone area.. RESULTS: There was a significant increase (p<.05) in the mean cortical area between the control group bones and the dose-response bones (3.6 mm2 versus 4.4 mm2). However, mechanical properties did not increase; peak moment was significantly less (-17%) and stiffness was reduced -23% in the delayed puberty animals compared to controls. There was also a statistically significant decrease (p<. 05) in the relative percentage of lamellar tissue when comparing the means of the control bones (41.4%) to the delayed puberty bones (16.8%). CONCLUSION: The decrease in lamellar bone in the delayed puberty animals may be a factor in the decreased mechanical strength in that group. The percentage of lamellar versus non-lamellar tissue contributes to a bone's overall mechanical tendencies.

Estrogen Receptor-alpha Genotype Affects Exercise And Nutrient Intake-related Change Of Bone Mass.

Bone mass is affected not only by environment factors, e.g., physical activities and foods, but also by gene polymorphism. PURPOSE: The present study was to determine whether gene polymorphism in the estrogen receptor (ER) alpha gene (ESR1) affect bone mass. And, the interaction between genes and physical activities and/or dietary intakes on bone mass in young women. METHODS: Seventy 20-23 years old Japanese women were chosen for the study. They wee euther very active physically (exercise three times per week) or not active. Food frequency questionnaires were used to estimate calcium intake. Bone mass was measured by quantitative ultrasound measurement (QUS). Genomic DNA was extracted from buccal cell. The ESR1 polymorphisms at intron I (Pvu II for a T/C substitution and Xba I for an A/G substitution) were genotyped using the PCR-RFLP. The relationships between ER1 genotype and physical activity, and/or dietary were evaluated. RESULTS: There were no significant differences between bone mass and ER1 genotypes. However, body weight, BMI and high physical activity showed the positive correlation with bone mass in the Pp heterozygote (P < 0.01). Furthermore, bone mass was higher in the individual who eats fish (three times per week) in the Xx heterozygote (P < 0.01). CONCLUSIONS: Our data suggested that physical exercise or a correct calcium intake is more important to bone mass for young women with Pp heterozygote or Xx heterozygote of ER alpha gene, respectively.

Menstrual irregularity is associated with higher bone mass in young women which is mediated through alterations in endogenous androgens

Background: There have been few studies examining the association between menstrual irregularity, androgens and bone mineral density in premenopausal women. Objective: To describe the association between menstrual irregularity, androgens and bone mass measured by quantitative ultrasound (QUS) in premenopausal women who were not taking hormonal contraceptives. Methods: Australia wide cross-sectional study (N=382, mean age 31 years). Menstrual irregularity was assessed based on selfadministered questionnaire. Bone mass was measured by Hologic Sahara densitometer. Total testosterone and SHBG were assessed by fasting blood sample and free androgen index was derived. Results: Women with irregular cycles (n=41, 11%) had higher SOS and QUI (median difference 6 m/s and 7.2% respectively, p<0.05) and a trend to higher BUA (5.1 dB/MHz, p=0.10). These associations persisted after adjustment for ambient temperature, age, BMI and smoking. Total testosterone, free androgen index and SHBG were associated with all QUS measures (testosterone and FAI r +0.11 to +0.21, all p<0.05; SHBG r −0.14 to −0.16, all p<0.05) and the associations remained significant after adjustment. However, the associations between menstrual irregularity and QUS were partially attenuated after adjustment for hormonal factors especially FAI becoming non significant at all sites. Conclusion: In our increasingly obesogenic society, irregular cycles are now associated with higher bone mass in a populationbased sample of premenopausal women. The association between menstrual irregularity and bone mass is, at least, partially mediated by free testosterone while total testosterone, FAI, and SHBG are independently associated with bone mass.

Daily Intake of Green and Yellow Vegetables Is Effective for Maintaining Bone Mass in Young Women

The increasing proportion of underweight young women may lead to an increase in those with low bone mass. The present study investigated whether bone mass level is associated with lifestyle factors among young Japanese women. A total of 103 Japanese female college students aged 20-21 majoring in food science participated in this cross-sectional study. We measured bone area ratio at the os calcis using quantitative ultrasound (QUS) and assessed lifestyle factors including diet and physical activity using a self-reported questionnaire. Bone area ratio was defined as a proportion of bone substance in a cross section of os trabeculare. Ninety-one subjects who completed the questionnaire were categorized into two groups according to the average bone area ratio of the 103 subjects (30.9%), calculated based on the screening method for osteoporosis prevention: 69 subjects with normal bone mass (bone area ratio: 36.2 +/- 3.8%) and 22 subjects with low bone mass (bone area ratio: 28.1 +/- 1.6%). In normal group, 12 subjects (17.4%) had a dietary habit of not daily intake of green and yellow vegetables, such as carrot and spinach, while this occurred in 10 subjects (45.5%) in low group (P = 0.007). Adjusted logistic regression analyses showed that the subjects without daily intake of green and yellow vegetables had almost 5-fold risk of low bone mass, compared to the subjects having daily intake of the vegetables [Odds ratio: 4.96 (95%CI 1.36-18.18)]. In conclusion, daily intake of green and yellow vegetables is effective for maintaining bone mass in young women.

Vitamin D Status and Its Relationship to Body Fat, Final Height, and Peak Bone Mass in Young Women

Vitamin D insufficiency has now reached epidemic proportions and has been linked to low bone mineral density, increased risk of fracture, and obesity in adults. However, this relationship has not been well characterized in young adults. The objective of the study was to examine the relationship between serum 25-hydroxyvitamin D (25OHD), anthropometric measures, body fat (BF), and bone structure at the time of peak bone mass. This was a cross-sectional study. OUTCOME MEASURES AND SUBJECTS: Anthropometric measures, serum 25OHD radioimmunoassay values, and computed tomography and dual-energy x-ray absorptiometry values of BF and bone structure in 90 postpubertal females, aged 16-22 yr, residing in California were measured. Approximately 59% of subjects were 25OHD insufficient (<or=29 ng/ml), and 41% were sufficient (>or=30 ng/ml). Strong negative relationships were present between serum 25OHD and computed tomography measures of visceral and sc fat and dual-energy x-ray absorptiometry values of BF. In addition, weight, body mass, and imaging measures of adiposity at all sites were significantly lower in women with normal serum 25OHD concentrations than women with insufficient levels. In contrast, no relationship was observed between circulating 25OHD concentrations and measures of bone mineral density at any site. Unexpectedly, there was a positive correlation between 25OHD levels and height. We found that vitamin D insufficiency is associated with increased BF and decreased height but not changes in peak bone mass.

Vitamin D Status and its Relationship to Body Fat, Final Height, and Peak Bone Mass in Young Women

Vitamin D Status and its Relationship to Body Fat, Final Height, and Peak Bone Mass in Young Women

Bone Mass in Young Women Is Dependent on Lean Body Mass

Relationships between bone mineral density (BMD) and body mass, height, fat mass, and lean mass have been reported. This study examined the relationship between body size and composition on bone density in young premenopausal women. In this study, a cross-sectional design was used. Seventy-one healthy women aged between 24 and 36 yr selected to have a wide range of boy habitus (mean body mass index, 22.7 ± 3.0) underwent a dual-energy X-ray absorptiometry (DXA) whole-body bone density scan (Hologic QDR 2000). Their bone density and soft tissue body composition and anthropometric parameters (skinfolds, girths, limb lengths, bone breadths, height, and body mass) were analyzed, and their body composition was assessed by underwater weighing (UWW). Bone-free lean mass (BFLM) determined by DXA was correlated with both bone mineral content (BMC) and BMD ( r = 0.74, p < 0.001; r = 0.48, p < 0.001, respectively). In addition, fat-free mass (FFM) determined by UWW was correlated with BMC and BMD ( r = 0.80, p < 0.001; r = 0.48, p < 0.001, respectively). Controlling for height in the model removed most of the correlations with whole-body BMD, with the exception of FFM, BFLM, and shoulder breadth ( r = 0.39, p < 0.001; r = 0.37, p < 0.01; and r = 0.34, p < 0.01, respectively). No correlation was found between fat mass by DXA, UWW, and sum of skinfolds and BMD. These results indicate that bone mass in premenopausal women is dependent on lean body mass.

Contraceptive pill decreases bone mass in young women

Contraceptive pill decreases bone mass in young women

Detrimental effect of oral contraceptives on parameters of bone mass and geometry in a cohort of 248 young women

The aim of this cross-sectional analysis was to examine the skeletal effects of low-dose monophasic oral contraceptive (OC) use in a cohort of 248 young Caucasian women aged 18–24 years. Areal bone mineral density (BMD) of the femoral neck and lumbar spine was evaluated by dual-energy X-ray absorptiometry. Volumetric BMD, bone mineral content (BMC), and bone geometry were assessed in the tibia by peripheral quantitative computed tomography (pQCT). The women were allocated into ever or never OC users, and also into 5 different OC groups according to duration and time of initiation of OC use. Women with > 2 years of OC use and OC initiation within 3 years after menarche were characterized by 10% lower femoral neck areal BMD ( P < 0.001), 5% lower spine areal BMD (not significant, P = 0.101), 7% lower distal tibial total BMC ( P < 0.05), and 6% lower total BMC at the tibial shaft ( P < 0.05) relative to never users. In addition, women who had ever used OCs had lower bone mass at the femoral neck and tibial shaft, despite similar age, height, weight, BMI, hours of exercise, and calcium intake compared with never users. At the tibial shaft, OC users showed reduced total cross-sectional area, and increased cortical BMD. In conclusion, our data suggest that OC use is associated with a detrimental effect on bone mass in young women, and provide further insight into the pathophysiological mechanisms involved.

Efficacy of optimization of vitamin D in preventing osteoporosis and osteoporotic fractures: A systematic review

Increased intake or supplementation of vitamin D is often recommended for normal bone health; however, its preventive effect on osteoporosis has not been fully evaluated. The aim of this review is to gather evidence of the efficacy of the optimization of vitamin D nutrition in preventing osteoporosis and osteoporotic fractures. PubMed was used for searching the relevant literature using the MeSH terms "Bone Density (limited to "human", "female", and "English" literature)" or "Fractures (limited to "human", "age ≥45 years", and "English" literature)", and "Vitamin D". The searches yielded 19 randomized controlled trials (RCTs), nine cohort studies, 19 case-control studies, 19 cross-sectional studies, and one meta-analysis. We attempted to answer three questions: 1) does increased vitamin D intake prevent bone loss in peri- and postmenopausal women?, 2) does increased vitamin D intake prevent osteoporotic fractures in the elderly?, and 3) does increased vitamin D in take positively affect peak bone mass attainment in young women? The answer to questions 1 and 2 is that a vitamin D intake of 10-17.5 μg/day (400-700 IU/day) or more is effective in preventing bone loss in late postmenopausal women and an intake of 17.5-20 μg/day (700-800 IU/day) or more together with a calcium supplement reduces the risk of osteoporotic fractures. For question 3, some lines of evidence support the negative effect of low vitamin D nutrition on the attainment of peak bone mass in young women. Further studies are needed to clarify the effect of vitamin D in this age group.

Nutrition, mild hyperparathyroidism, and bone mineral density in young Japanese women

The adverse effects of poor nutrition on the bones of young Asian women have not been fully elucidated. The purpose of this study was to investigate possible associations of vitamin D nutrition, calcium intake, and other nutrients with bone metabolism and bone mass in young Japanese women. The subjects were 108 female college students aged 19-25 y. Dietary nutrients were measured by using the duplicate sampling method on 3 weekdays. Serum 25-hydroxyvitamin D [25(OH)D], intact parathyroid hormone, and bone turnover markers were also measured. Bone mineral density (BMD) of the spine and femur was measured by dual-energy X-ray absorptiometry. The proportions of the subjects with low 25(OH)D (< 30 nmol/L) and high intact parathyroid hormone (> or = 6.9 pmol/L) concentrations were 32.4% and 15.7%, respectively. Serum 25(OH)D concentrations (P = 0.0265) and calcium intake (P = 0.0103) were inversely associated with serum intact parathyroid hormone. In addition to weight and physical activity, the presence of mild hyperparathyroidism was associated with a low BMD of the lumbar spine (P = 0.0062) and the femoral neck (P = 0.0250), and a low calcium intake was associated with a low BMD of the femoral neck (P = 0.0044). Low calcium intake (based on low BMD of the femoral neck only) and mild hyperparathyroidism (based on low BMD of both the femoral neck and lumbar spine), partly explained by low vitamin D nutrition and a low calcium intake, are important predictors of low BMD in young Japanese women. Effects of poor nutrition and mild hyperparathyroidism on bone peak bone mass in young women should be further investigated in longitudinal studies.

Weight gain in childhood and bone mass in female college students

The attainment of maximal peak bone mass early on in life is one of the most important strategies for the prevention of osteoporosis in women. The aim of this study was to clarify the correlation between gains in body size in all growth phases in childhood and adult bone mass in women. The subjects were 86 female first-year university students, aged 18-21 years. We measured the subjects' bone mineral content (BMC) and bone mineral density (BMD) at the lumbar spine and the left hip, including the femoral neck, with dual energy X-ray absorptiometry. Each subject was measured for current height and weight. Height and weight at birth, and at 1.5, and 3 years were obtained from each maternity record book, and those between 6 and 18 years were obtained from their school health records. Other information, including physical activity and calcium intake, was obtained through an interview. Bivariate analysis showed that weight gains during the periods from birth to 1.5 years and from 9 to 12 years significantly correlated with both BMC and BMD values at any site. The stepwise method of multiple regression analysis showed that a weight gain during the period from birth to 1.5 years was significantly associated with BMC at the lumbar spine (P = 0.0001) and at the femoral neck (P = 0.0290) and with BMD at the lumbar spine (P = 0.0387). Birth weight was significantly associated with BMC at the lumbar spine (P = 0.0474) and the total hip (P = 0.0352), and weight gain during the period from 9 to 12 years was significantly associated with BMC at the femoral neck (P = 0.0376). In conclusion, birth weight and weight gain in infancy are important determinants of bone mass in young women. Additionally, a girl's prepubertal growth spurt is likely to be a key phase for the acquisition of bone mass in relation to body weight. Our findings suggest that osteoporosis prevention programs may need to start very early in the life cycle.

Age at first oral contraceptive use as a major determinant of vertebral bone mass in female endurance athletes

It was the aim of this retrospective analysis to examine the influence of low-dose monophasic oral contraceptives (OCs) on bone mineral density (BMD) of the femoral neck and of the spine in young female endurance athletes. Data on training intensity, dietary intake, menarche, menstrual cycle disorders, years of OC use, and age at first OC use were determined by a self-report questionnaire. Only athletes performing regular endurance exercise for more than 3 years with more than 3 h of exercise per week were included in this study and underwent a clinical assessment including measurement of weight, height, spine, and hip BMD by dual-energy X-ray absorptiometry, and collection of a blood sample. The data from 75 regularly exercising endurance athletes aged 18–35 years (26.5 ± 4.8 years) were initially included in this analysis. Six athletes were later excluded due to oligo-/amenorrhea. Subjects were allocated into the OC group when they reported OC use for more than 3 years in women younger than 22 years of age, or when they reported OC use for more than 50% of the time after menarche in women aged 22–35 years. There were no differences in age, weight, height, body mass index (BMI), body fat, menarche, training intensity, age at start of training, or any serum parameters between OC users ( n = 31) and control subjects ( n = 38). However, OC users had 7.9% lower spine BMD and 8.8% lower proximal femur BMD ( P < 0.01 for both sites). When the relationship between BMD of the spine and OC use was further analyzed by a stepwise model of multiple regression analysis using OC years, age at OC initiation, BMI, and menarche as independent variables, age at first OC use was found to be the best predictor of vertebral BMD, while the only significant predictor of femoral neck BMD was BMI. We conclude that OC use is associated with decreased BMD of the spine and the femoral neck in female endurance athletes, and that early age at initiation of OC use may be an important risk factor for low peak bone mass in young women.