An Increase in Forearm Cortical Bone Size After Menopause May Influence the Estimated Bone Mineral Loss--A 28-Year Prospective Observational Study.

Areal bone mineral density (aBMD) is the most common estimate of bone mass, incorporated in the World Health Organization definition of osteoporosis. However, aBMD depends on not only the amount of mineral but also the bone size. The estimated postmenopausal decline in aBMD could because of this be influenced by changes in bone size.We measured bone mineral content (BMC; mg), aBMD (mg/cm2), and bone width (mm) by single-photon absorptiometry at the cortical site of the forearm in a population-based sample of 105 Caucasian women. We conducted 12 measurements during a 28-yr period from mean 5 yr (range: 2-9) before menopause to mean 24 yr (range: 18-28) after menopause. We calculated individual slopes for changes in the periods before menopause, 0-<8, 8-<16, and 16-28 yr after menopause. Data are presented as means with 95% confidence intervals. The annual BMC changes in the 4 periods were -1.4% (-0.1, -2.6), -1.1% (-0.9, -1.4), -1.2% (-0.9, -1.6), and -1.1% (-0.8, -1.4) and the annual increase in bone width 0.4% (-1.2, 1.9), 0.7% (0.5, 0.9), 0.1% (-0.2, 0.4), and 0.1% (-0.2, 0.4). BMC loss was similar in all periods, whereas the increase in bone width was higher in the first postmenopausal period than in the second (p=0.003) and the third (p=0.01) postmenopausal periods. Menopause is followed by a transient increase in forearm bone size that will influence the by aBMD estimated cortical loss in bone minerals.

Gender specific age-related changes in bone density, muscle strength and functional performance in the elderly: a-10 year prospective population-based study.

BACKGROUND: Age-related losses in bone mineral density (BMD), muscle strength, balance, and gait have been linked to an increased risk of falls, fractures and disability, but few prospective studies have compared the timing, rate and pattern of changes in each of these measures in middle-aged and older men and women. This is important so that targeted strategies can be developed to optimise specific musculoskeletal and functional performance measures in older adults. Thus, the aim of this 10-year prospective study was to: 1) characterize and compare age- and gender-specific changes in BMD, grip strength, balance and gait in adults aged 50 years and over, and 2) compare the relative rates of changes between each of these musculoskeletal and functional parameters with ageing. METHODS: Men (n = 152) and women (n = 206) aged 50, 60, 70 and 80 years recruited for a population-based study had forearm BMD, grip strength, balance and gait velocity re-assessed after 10-years. RESULTS: The annual loss in BMD was 0.5-0.7% greater in women compared to men aged 60 years and older (p < 0.05- < 0.001), but there were no gender differences in the rate of loss in grip strength, balance or gait. From the age of 50 years there was a consistent pattern of loss in grip strength, while the greatest deterioration in balance and gait occurred from 60 and 70 years onwards, respectively. Comparison of the changes between the different measures revealed that the annual loss in grip strength in men and women aged <70 years was 1-3% greater than the decline in BMD, balance and gait velocity. CONCLUSION: There were no gender differences in the timing (age) and rate (magnitude) of decline in grip strength, balance or gait in Swedish adults aged 50 years and older, but forearm BMD decreased at a greater rate in women than in men. Furthermore, there was heterogeneity in the rate of loss between the different musculoskeletal and function parameters, especially prior to the age of 70 years, with grip strength deteriorating at a greater rate than BMD, balance and gait.

Low BMD is an independent predictor of fracture and early menopause of mortality in post-menopausal women--a 34-year prospective study.

OBJECTIVE: Identify risk factors for fragility fractures and mortality in women aged 48. STUDY DESIGN: Prospective population-based observational study on 390 white north European women aged 48 at study start. At study start, we measured bone mineral density (BMD) by single-photon absorptiometry (SPA) in the distal forearm, anthropometry by standard equipment and registered menopausal status, health and lifestyle factors. Menopause before age 47 was defined as early menopause. Incident fragility fractures and mortality were recorded until the women reached age 82. Potential risk factors for fragility fracture and mortality were evaluated with Cox's proportional hazard regression analysis. Data are presented as risk ratios (RR) with 95% confidence intervals in brackets. MAIN OUTCOME MEASURES: Incidence of fragility fractures and mortality. RESULTS: In the univariate analysis, low BMD and early menopause predicted fractures. In the multivariate analysis, only BMD remained as an independent risk factor with a RR of 1.36 (1.15, 1.62) per standard deviation (SD) decrease in baseline BMD. In the univariate analysis, early menopause and smoking predicted mortality, and remained as independent risk factors in the multivariate analysis with RR 1.62 (1.09, 2.39) for early menopause and 2.16 (1.53, 3,06) for smoking. CONCLUSIONS: Low BMD at age 48 is an independent predictor for fragility fractures. The predictive ability of early menopause is at least partially attributed to other associated risk factors. Early menopause and smoking were found in this study to be independent predictors for mortality.

Secular trends in Swedish hip fractures 1987-2002: birth cohort and period effects.

BACKGROUND: Recently, a leveling off in hip-fracture incidence has been reported in several settings, but the annual number is nonetheless predicted to increase due to the growing elderly population. METHODS: Using Swedish national data for 1987-2002 for all inpatients 50 years or older, we examined the annual number and incidence of hip fractures and explored age, period, and cohort effects. Age adjustment was done by direct standardization, time-trend analysis by linear regression, changes in linear trends by joinpoint regression, and age-period-cohort effects by log-likelihood estimates in Poisson regression models. RESULTS: Before 1996, the age-standardized hip fracture incidence was stable (0.1% per year [95% confidence interval = -0.2% to 0.5%]), and the annual number of hip fractures increased (2.1% per year [1.8% to 2.4%]). After 1996, both the age-standardized hip fracture incidence (-2.2% per year [-2.8% to -1.6%]) and the number of hip fractures (-0.9% per year [-1.5% to -0.4%]) decreased. The period + cohort effects were more marked among women than men, with a major reduction in hip fracture incidence in subsequent birth cohorts (estimated incidence rate ratio = 2.2 comparing women born 1889-1896 with 1945-1952) or periods (estimated incidence rate ratio = 1.1 comparing women living 1987-1990 with 1999-2002). CONCLUSION: The age-standardized hip fracture incidence has decreased since 1996, more than counteracting the effects of the aging population and resulting in a decline in the annual number of hip fractures through 2002. The magnitude of the combined period and cohort effects in women seems to be of biologic importance. If this persists into older age, the annual number of hip fractures will be lower than has been projected.

Forearm bone mineral density and incidence of hip fractures in Swedish urban and rural men 1987-2002.

BACKGROUND: It is not known whether the recently described break in the trend in hip fracture incidence in many settings applies in both women and men, depends on changes in bone mineral density (BMD) or changes in other risk factors, or whether it is apparent in both urban and rural settings. METHODS: We evaluated changes in annual hip fracture incidence from 1987 to 2002 in Swedish men aged ≥60 years in one urban (n = 25,491) and one rural population (n = 16,432) and also secular differences in BMD, measured by single-photon absorptiometry at the distal radius and multiple other risk factors for hip fracture in a population-based sub-sample of the urban and the rural men aged 60-80 years in 1988/89 (n = 202 vs. 121) and in 1998/99 (n = 79 vs. 69). RESULTS: No statistically significant changes in the annual age-adjusted hip fracture incidence per 10,000 were apparent from 1987 to 2002 in urban (0.38 per year, 95% CI -0.12 to 0.88) or rural men (-0.05 per year, 95% CI -0.63 to 0.53). BMD was similar in 1988/89 and 1998/99 when examining both urban (-19.6 mg/cm(2), 95% CI -42.6 to 3.5) and rural (-23.0 mg/cm(2), 95% CI -52.1 to 6.1) men. CONCLUSIONS: Since no secular change in age-adjusted hip fracture incidence was found during the study period, a levelling off in hip fracture incidence is present also in Swedish men. Because BMD on a group level was similar in 1988/89 and 1998/99, changes in other risk factors ought to be either of minor importance or counteracted by changes in different risk factors.

Bone mineral density and incidence of hip fracture in Swedish urban and rural women 1987-2002.

BACKGROUND AND PURPOSE: Although the incidence of hip fracture during the past 50 years has increased, a break in this trend has been reported in the last decade. Whether this change is attributable to changes in bone mineral density (BMD) or whether it varies between urban and rural regions is unknown. METHODS: We evaluated changes in annual hip fracture incidence in women aged > or = 50 years in one urban population (n = 51,757) and one rural population (n = 26,446) from 1987 to 2002. We also examined secular differences in BMD (mg/cm(2)), evaluated by single-photon absorptiometry at the distal radius, prevalence of osteoporosis, and several other risk factors for hip fracture in one population-based sample of urban women and one sample of rural women aged 50-80 years at two time points: 1988/89 (n = 257 and n = 180, respectively) and 1998/99 (n = 171 and n = 118, respectively). RESULTS: No statistically significant changes were evident in annual age-adjusted hip fracture incidence per 10(4) when analyzing all women (-0.01 per year (95% CI: -0.37, 0.35)), rural women (-0.38 per year (-1.05, 0.28)), or urban women (0.19 per year (-0.28, 0.67)). BMD (expressed as T-score) was similar in 1988/99 and 1998/99 when analyzing all women (-0.09 (-0.26, 0.09)), urban women (-0.04 (-0.27, 0.19)), or rural women (-0.15 (-0.42, 0.13)) women. INTERPRETATION: Since no changes in age-adjusted hip fracture incidence and no differences in BMD were found during the study period, changes evident in the other risk factors for hip fracture that we investigated (such as gait velocity and balance) are either of minor importance or are counteracted by changes in other risk factors.

Prevalence of osteoporosis and incidence of hip fracture in women--secular trends over 30 years.

BACKGROUND: The number of hip fractures during recent decades has been reported to be increasing, partly because of an increasing proportion of elderly women in the society. However, whether changes in hip fracture annual incidence in women are attributable to secular changes in the prevalence of osteoporosis is unclear. METHODS: Bone mineral density was evaluated by single-photon absorptiometry at the distal radius in 456 women aged 50 years or above and living in the same city. The measurements were obtained by the same densitometer during three separate time periods: 1970-74 (n = 106), 1987-93 (n = 175) and 1998-1999 (n = 178), and the age-adjusted prevalence of osteoporosis in these three cohorts was calculated. Additionally, all hip fractures sustained in the target population of women aged 50 years or above between 1967 and 2001 were registered, whereupon the crude and the age-adjusted annual incidence of hip fractures were calculated. RESULTS: There was no significant difference in the age-adjusted prevalence of osteoporosis when the three cohorts were compared (P = 1.00). The crude annual incidence (per 10,000 women) of hip fracture in the target population increased by 110% from 40 in 1967 to 84 in 2001. The overall trend in the crude incidence between 1967 and 2001 was increasing (1.58 per 10,000 women per year; 95 percent confidence interval, 1.17 to 1.99), whereas the age-adjusted incidence was stable over the same period (0.22 per 10,000 women per year; 95 percent confidence interval, -0.16 to 0.60). CONCLUSIONS: The increased number of hip fracture in elderly women is more likely to be attributable to demographic changes in the population than to secular increase in the prevalence of osteoporosis.

Low calcaneal bone mineral density and the risk of distal forearm fracture in women and men: a population-based case-control study.

OBJECTIVE: We used dual X-ray absorptiometry (DXA) to measure calcaneal bone mineral density (BMD) and estimate the prevalence of osteoporosis in a population with distal forearm fracture and a normative cohort. METHODS: Patients 20 to 80 years of age with distal forearm fracture treated at one emergency hospital during two consecutive years were invited to calcaneal BMD measurement; 270 women (81%) and 64 men (73%) participated. A DXA heel scanner estimated BMD (g/cm(2)) and T-scores. Osteoporosis was defined as T-score< or =-2.5 SD. Of the fracture cohort, 254 women aged 40-80 years and 27 men aged 60-80 years were compared with population-based control cohorts comprising 171 women in the age groups 50, 60, 70 and 80 years and 75 men in the age groups 60, 70, and 80 years. RESULTS: In the fracture population no woman below 40 years or man below 60 years of age had osteoporosis. In women aged 40-80 years the prevalence of osteoporosis in the distal forearm fracture cohort was 34% and in the population-based controls was 25%; the age-adjusted prevalence ratio (PR) was 1.32 (95% CI 1.00-1.76). In the subgroup of women aged 60-80 years the age-adjusted prevalence ratio of osteoporosis was 1.28 (95% CI 0.95-1.71). In men aged 60-80 years the prevalence of osteoporosis in the fracture cohort was 44% and in the population-based controls was 8% (PR 6.31, 95% CI 2.78-14.4). The age-adjusted odds ratio for fracture associated with a 1-SD reduction in calcaneal BMD was in women aged 40-80 years 1.4 (95% CI 1.1-1.8), in the subgroup of women aged 60-80 years 1.2 (95% CI 0.95-1.6), and in men aged 60-80 years 2.6 (95% CI 1.7-4.1). Among those aged 60-80 years the area under the ROC curve was in women 0.56 (95% CI 0.49-0.63) and in men 0.80 (95% CI 0.70-0.80). CONCLUSIONS: The age-adjusted prevalence of osteoporosis based on calcaneal BMD is higher in individuals with distal forearm fracture than in population-based controls. BMD impairment is associated with increased odds ratio for forearm fracture in both women and men but the differences between cases and controls are more pronounced in men than in women, which may have implications in fracture prevention.

Association between changes in habitual physical activity and changes in bone density, muscle strength, and functional performance in elderly men and women.

OBJECTIVES: To investigate the long-term effects of habitual physical activity on changes in musculoskeletal health, functional performance, and fracture risk in elderly men and women. DESIGN: Ten-year prospective population-based study. SETTING: Malmö-Sjöbo Prospective Study, Sweden. PARTICIPANTS: Participants were 152 men and 206 women aged 50, 60, 70, and 80 who were followed for 10 years. MEASUREMENTS: Distal radius bone mineral density (BMD) (single photon absorptiometry), upper limb muscle (grip) strength, balance, gait velocity, occupational and leisure-time activity, and fractures (interview-administered questionnaire) were reassessed after 10 years. Annual changes for all measures were compared between participants with varying habitual physical activity histories at baseline and follow-up: inactive-inactive (n=202), active-inactive (n=47), inactive-active (n=49), and active-active (n=60). Data for men and women were pooled, because there were no sex-by-activity group interactions. To detect possible differences in fracture incidence between the varying habitual activity groups, participants were classified into two activity groups based on their activity classification at baseline and follow-up: inactive:less active versus active:more active. RESULTS: The annual rate of bone loss was 0.6% per year less in individuals classified as active at both time points than in those classified as inactive at both time points (P<.01). Similar results were observed for balance, but there was no effect of varying habitual activity on changes in muscle strength or gait velocity. There were also no differences in fracture incidence between individuals categorized as active:more active and those categorized as inactive:less active during the follow-up (adjusted hazard ratio=0.90, 95% confidence interval (CI)=0.42-1.90). CONCLUSION: This study showed that elderly men and women who maintained a habitually active lifestyle over 10 years had lower bone loss and retained better balance than those who remained habitually inactive.

A 2-year school-based exercise programme in pre-pubertal boys induces skeletal benefits in lumbar spine.

AIM: The aim of this study was to evaluate if a general school-based exercise intervention programme in pre-pubertal boys would render site-specific benefits in bone mineral accrual and gain in femoral neck structure. METHODS: Eighty boys aged 7-9 years were included in a curriculum-based exercise intervention programme comprising 40 min of general physical activity per school day (200 min/week) for 2 years. Fifty-seven age-matched boys, assigned to the general Swedish school curriculum of 60 min/week, served as controls. Bone mineral content was measured with dual X-ray absorptiometry of the total body, the third lumbar vertebra and hip. Specific software, the hip structural analyses, evaluated the structural properties of the femoral neck. Annual changes were compared. The level of physical activity was estimated through questionnaires and accelerometers. RESULTS: The mean annual bone mineral content gain in third lumbar vertebra was 3.0 percentage points (p < 0.01) and in width 1.3 percentage points (p < 0.01) greater in the intervention than in the control group. The weekly duration of exercise estimated through the questionnaire correlated with gain in bone mineral content in third lumbar vertebra (r = 0.25, p = 0.005) and vertebra width (r = 0.20, p = 0.02). CONCLUSION: A school-based exercise intervention programme in pre-pubertal boys enhances the skeletal benefits at lumbar spine.

Incidence and risk factors for low trauma fractures in men with prostate cancer.

BACKGROUND: Men with prostate cancer on androgen deprivation therapy (ADT) are at increased risk of bone loss. The present study sought to determine the incidence of low trauma fracture in men with prostate cancer (PC), and to characterize the association between potential risk factors and fracture risk in these men. METHODS: In the prospective, population-based Dubbo Osteoporosis Epidemiology Study, 43 men aged 60+ years reported a history of prostate cancer; among whom, 22 men received ADT, and 21 men did not. Low-trauma fractures were ascertained between 1989 and 2004. Bone mineral density at the femoral neck (FNBMD), postural instability and lifestyle factors were obtained at baseline. RESULTS: Men with prostate cancer had significantly higher lumbar spine BMD than those without cancer (p=0.013). During the follow-up period, 15 men with prostate cancer had sustained a fracture, yielding the age-adjusted incidence of fracture among this group was 31.6 per 1000 person-years, which was greater than those without cancer (22.1 per 1000 person-years). The age-adjusted incidence of fracture was more pronounced among those with prostate cancer on ADT (40.2 per 1000 person-years). After adjusting for age, the increase in fracture risk among prostate cancer patients was associated with lower femoral neck BMD (hazard ratio [HR] per SD=1.8, 95% CI: 1.0-3.4) and increased rate of bone loss (HR 2.3, 1.2-4.6). CONCLUSIONS: Men with prostate cancer, particularly those treated with ADT, had an increased fracture risk. Although the average BMD in men with prostate cancer was higher than men without cancer, a low BMD prior to treatment or increased rate of bone loss after initiating ADT treatment was each a significant predictor of fracture in these.

A school-curriculum-based exercise intervention program for two years in pre-pubertal girls does not influence hip structure.

BACKGROUND: It is known that physical activity during growth has a positive influence on bone mineral accrual, and is thus possibly one strategy to prevent osteoporosis. However, as bone geometry, independent of areal bone mineral density (aBMD), influences fracture risk, this study aimed to evaluate whether hip structure in pre-pubertal girls is also affected by a two-year exercise intervention program. METHODS: Forty-two girls aged 7-9 years in a school-curriculum-based exercise intervention program comprising 40 minutes of general physical activity per school day (200 minutes per week) were compared with 43 age-matched girls who participated in the general Swedish physical education curriculum comprising a mean of 60 minutes per week. The hip was scanned by dual energy X-ray absorptiometry (DXA) and the hip structural analysis (HSA) software was applied to evaluate bone mineral content (BMC, g), areal bone mineral density (aBMD, g/cm2), periosteal diameter, cross-sectional area (CSA, cm2), section modulus (Z, cm3) and cross-sectional moment of inertia (CSMI, cm4) of the femoral neck (FN). Annual changes were compared. Subjective duration of physical activity was estimated by questionnaire and objective level of everyday physical activity at follow-up by means of accelerometers worn for four consecutive days. All children remained at Tanner stage 1 throughout the study. Group comparisons were made by independent student's t-test between means and analyses of covariance (ANCOVA). RESULTS: At baseline, the two groups did not differ with regard to age, anthropometrics or bone parameters. No between-group differences were observed for annual changes in the FN variables measured. CONCLUSION: A two-year school-based moderately intense general exercise program for 7-9-year-old pre-pubertal girls does not influence structural changes in the FN.

A one-year exercise intervention program in pre-pubertal girls does not influence hip structure.

BACKGROUND: We have previously reported that a one-year school-based exercise intervention program influences the accrual of bone mineral in pre-pubertal girls. This report aims to evaluate if also hip structure is affected, as geometry independent of bone mineral influences fracture risk. METHODS: Fifty-three girls aged 7 - 9 years were included in a curriculum-based exercise intervention program comprising 40 minutes of general physical activity per school day (200 minutes/week). Fifty healthy age-matched girls who participated in the general Swedish physical education curriculum (60 minutes/week) served as controls. The hip was scanned by dual X-ray absorptiometry (DXA) and the hip structural analysis (HSA) software was applied to evaluate bone mineral content (BMC), areal bone mineral density (aBMD), periosteal and endosteal diameter, cortical thickness, cross-sectional moment of inertia (CSMI), section modulus (Z) and cross-sectional area (CSA) of the femoral neck (FN). Annual changes were compared. Group comparisons were done by independent student's t-test between means and analyses of covariance (ANCOVA). Pearson's correlation test was used to evaluate associations between activity level and annual changes in FN. All children remained at Tanner stage 1 throughout the study. RESULTS: No between-group differences were found during the 12 months study period for changes in the FN variables. The total duration of exercise during the year was not correlated with the changes in the FN traits. CONCLUSION: Evaluated by the DXA technique and the HSA software, a general one-year school-based exercise program for 7-9-year-old pre-pubertal girls seems not to influence the structure of the hip.

Residual lifetime risk of fractures in women and men.

UNLABELLED: In a sample of 1358 women and 858 men, > or = 60 yr of age who have been followed-up for up to 15 yr, it was estimated that the mortality-adjusted residual lifetime risk of fracture was 44% for women and 25% for men. Among those with BMD T-scores < or = -2.5, the risks increased to 65% in women and 42% in men. INTRODUCTION: Risk assessment of osteoporotic fracture is shifting from relative risk to an absolute risk approach. Whereas BMD is a primary predictor of fracture risk, there has been no estimate of mortality-adjusted lifetime risk of fracture by BMD level. The aim of the study was to estimate the residual lifetime risk of fracture (RLRF) in elderly men and women. MATERIALS AND METHODS: Data from 1358 women and 858 men > or = 60 yr of age as of 1989 of white background from the Dubbo Osteoporosis Epidemiology Study were analyzed. The participants have been followed for up to 15 yr. During the follow-up period, incidence of low-trauma, nonpathological fractures, confirmed by X-ray and personal interview, were recorded. Incidence of mortality was also recorded. BMD at the femoral neck was measured by DXA (GE-LUNAR) at baseline. Residual lifetime risk of fracture from the age of 60 was estimated by the survival analysis taking into account the competing risk of death. RESULTS: After adjusting for competing risk of death, the RLRF for women and men from age 60 was 44% (95% CI, 40-48) and 25% (95% CI, 19-31), respectively. For individuals with osteoporosis (BMD T-scores < or = -2.5), the mortality-adjusted lifetime risk of any fracture was 65% (95% CI, 58-73) for women and 42% (95% CI, 24-71) for men. For the entire cohort, the lifetime risk of hip fracture was 8.5% (95% CI, 6-11%) for women and 4% (95% CI, 1.3-5.4%) for men; risk of symptomatic vertebral fracture was 18% (95% CI, 15-21%) for women and 11% (95% CI, 7-14%) for men. CONCLUSIONS: These estimates provide a means to communicate the absolute risk of fracture to an individual patient and can help promote the identification and targeting of high-risk individuals for intervention.

A school curriculum-based exercise program increases bone mineral accrual and bone size in prepubertal girls: two-year data from the pediatric osteoporosis prevention (POP) study.

UNLABELLED: This 2-year prospective controlled exercise intervention trial in 99 girls at Tanner stage 1, evaluating a school curriculum-based training program on a population-based level, showed that the annual gain in BMC, aBMD, and bone size was greater in the intervention group than in the controls. INTRODUCTION: Most exercise intervention studies in children, evaluating the accrual of BMD, include volunteers and use specifically designed osteogenic exercise programs. The aim of this study was to evaluate a 2-year general school-based exercise intervention program in a population-based cohort of girls at Tanner stage 1. MATERIALS AND METHODS: Forty-nine girls 7-9 years of age in grades 1 and 2 in one school were included in a school curriculum-based exercise intervention program of general physical activity for 40 minutes per school day (200 minutes/week). Fifty healthy age-matched girls in three neighboring schools, assigned to the general Swedish school curriculum of physical activity (60 minutes/week), served as controls. All girls were premenarchal, remaining in Tanner stage 1 during the study. BMC (g) and areal BMD (aBMD; g/cm2) were measured with DXA of the total body (TB), the lumbar spine (L2-L4 vertebrae), the third lumbar vertebra (L3), the femoral neck (FN), and the leg. Volumetric BMD (vBMD; g/cm3) and bone size were calculated at L3 and FN. Total lean body mass and total fat mass were estimated from the total body scan. Height and weight were also registered. Baseline measurements were performed before the intervention was initiated. Follow-up was done after 2 years. RESULTS: No differences between the groups were found at baseline in age, anthropometrics, or bone parameters. The annual gain in BMC was greater in the intervention group than in the controls: L2-L4, mean 3.8 percentage points (p = 0.007); L3 vertebra, mean 7.2 percentage points (p < 0.001); legs, mean 3.0 percentage points (p = 0.07). The intervention group had a greater annual gain in aBMD: total body, mean 0.6 percentage points (p = 0.006), L2-L4, mean 1.2 percentage points (p = 0.02), L3 vertebra, mean 1.6 percentage points (p = 0.006); legs, mean 1.2 percentage points (p = 0.007). There was also a greater mean annual gain in bone size in the L3 vertebra (mean 1.8 percentage points; p < 0.001) and in the FN (mean 0.3 percentage points; p = 0.02). CONCLUSIONS: A general school-based exercise program for 2 years for 7- to 9-year-old girls (baseline) enhances the accrual of BMC and BMD and increases bone size.

Contribution of hip strength indices to hip fracture risk in elderly men and women.

UNLABELLED: In this prospective, case-control study, femoral neck diameter, cross-sectional moment of inertia, or section modulus was an independent predictor of hip fracture risk after adjustment for BMD. However, the contribution of each of these indices to hip fracture prediction was modest in the presence of BMD. INTRODUCTION: The relative contribution of measures of hip strength to hip fracture prediction is unclear. This study was designed to characterize the association between hip strength indices and hip fracture risk in relation to BMD in elderly men and women. MATERIALS AND METHODS: Seventy-one women and 25 men>or=60 years of age, who sustained a hip fracture during the study period of 1989-2003, were selected from the prospective, population-based Dubbo Osteoporosis Epidemiology Study. These fracture cases were randomly matched for age and sex in a 1:2 ratio with nonfracture individuals. BMD at the femoral neck was measured before the fracture event by DXA (Lunar DPX-L). Hip strength indices, including femoral neck diameter (FND), cross-sectional moment of inertia (CSMI), and section modulus (Z), were estimated by reanalysis of the image files using hip strength analysis software. RESULTS: In women, after adjustment for BMD, increased risk of hip fracture was associated with smaller FND (OR, 1.6; 95% CI, 1.0, 2.7), lower CSMI (OR, 1.8; 95% CI, 1.0, 3.2), or Z (OR, 1.6; 95% CI, 1.1, 5.1). In men, none of these hip strength indices were significant predictors of fracture risk. However, using the results in women as a prior distribution, it was estimated that the BMD-adjusted OR for FND (OR, 1.5; 95% CI, 1.0, 2.3), CSMI (OR, 1.6; 95% CI, 1.0, 2.5), or Z (OR, 2.3; 95% CI, 1.4, 3.9) was each significantly associated with hip fracture risk in men. In the logistic regression model, BMD alone accounted for 32% and 16% of the variance of fracture liability in women and men, respectively. The addition of FND, CSMI, or Z to the model increased the respective variance proportion to 34% and 19%. CONCLUSIONS: These data suggest that smaller FND and lower CSMI or Z is an independent risk factor for hip fracture in both women and men. However, the contribution of these measures to hip fracture prediction over and above BMD is likely modest.

Maternity and bone mineral density.

During pregnancy and lactation, changes occur in a variety of factors which have great potential to influence bone mineral density (BMD). Smoking habits, the level of alcohol consumption, the level of physical activity, body weight, soft tissue composition and hormone levels are all factors that change during the course of these conditions. Some of these factors are capable of increasing BMD, and some can reduce it. Due to these various changes, it is virtually impossible to predict the development in BMD that will occur during a pregnancy and lactation. However, longitudinal studies have suggested that both pregnancy and lactation are associated with a BMD loss of up to 5%, albeit that the BMD recovers after weaning. Cross-sectional studies have indicated that women with many children and a long total period of lactation have similar or higher BMD and similar or lower fracture risk than their peers who have not given birth. As the studies showing this trend have been observational and cross sectional case-control studies, the conclusions can only be regarded as being suggestive, and no causality can be proven.

[Pregnancy and lactation are not risk factors for osteoporosis or fractures]. / Graviditet och amning ar inte riskfaktorer för osteoporos eller fraktur.

Observational and case control studies infer that a pregnancy and a period of lactation are followed by loss in bone mass of up to 5%. The reason for this loss is virtually impossible to conclude as so many factors known to influence the bone mass undergo changes during a pregnancy and lactation. The increased calcium demand, changed nutritional habits, reduced smoking and alcohol consumption seen in many women during these periods, the changes in body weight and fat content, the changed level of physical activity and the changed levels of hormones with potential to influence the bone metabolism could all influence the bone mass. Most studies also report that the deficit in "bone mass" normalises after weaning. Multiple pregnancies and long total duration of lactation can not be regarded as risk factors for osteoporosis and fragility fractures as most reports indicate that women with multiple pregnancies have similar or higher bone mass and similar or lower fracture incidence than their peers with no children.