Bone mineral density in Norwegian premenopausal women

The influence of lactation and its duration on bone mineral density in pregnancy and postpartum: A systematic review with meta-analysis

BACKGROUND

There is a plethora of research on the association of parity and duration of lactation with bone mineral density (BMD) during and after pregnancy. However, there are no consensus conclusions on the impact of the duration of lactation on BMD.

AIMS

The aim of this study was to examine the effect of pregnancy, and the duration of lactation on BMD during pregnancy, postpartum phase and 12 months post-delivery.

METHODS

The search terms 'parity' 'lactation' 'BMD' were searched for using PubMed, CINAHL, SCOPUS and EMBASE databases in English language. Two independent reviewers assessed the quality of the included studies using Critical Appraisal Skills Program (CASP) appraisal tool and extracted data on BMD (g/cm²) in Excel. A meta-analysis was conducted with a random effect model using Cochrane Review Manager (Rev 5.4) to analyse the outcome. Heterogeneity was assessed with Chi Squared and I² test. The duration of lactation was grouped into short lactation duration (SLD), ≤4 months and longer lactation duration (LLD) > 6 months.

RESULTS

Twenty-one studies were included in this review with four studies included in the meta-analysis. BMD reduced during pregnancy and lactation. Recovery and net gains in BMD followed weaning. However, at 12 months postpartum, women in the LLD group had significant losses at the lumbar spine while those in the SLD recovered BMD. Between the SLD and LLD groups, the change in BMD was not significant 0.48 g/cm² (95% CI -0.14, 1.10, p = 0.13). BMD losses were greater in primiparous women than multiparous women.

CONCLUSION

Women who breastfed for >6 months had significantly reduced BMD. However, compared to women that breastfed for a ≤4 months there was no significant change in BMD. Further investigation is needed to clarify the association between lactation and BMD in a postpartum population in those women extending breastfeeding beyond one year.

Bone mineral density is close to normal for age in long-term lymphoma survivors treated with high-dose therapy with autologous stem cell transplantation

BACKGROUND

Few studies have assessed bone health in lymphoma survivors treated with high-dose therapy with autologous stem cell transplantation (HDT-ASCT). Therefore, we aimed to assess bone mineral density (BMD) at six different skeletal sites and to investigate associations between clinical factors and BMD in these survivors.

MATERIAL AND METHODS

Eligible lymphoma survivors were aged ≥18 years at diagnosis and at HDT-ASCT given between 1987 and 2008. Participants responded to questionnaires, blood samples were drawn, and a dual energy X-ray absorptiometry (DXA) was performed. Mean Z-score was applied for assessment of BMD in relation to age. Prevalence of Z-scores ≥-1, between -1 and -2, and ≤-2 is reported for each measurement site and for the lumbar spine, femoral neck, and hip in combination. Likewise, T-scores were applied to assess the prevalence of normal BMD (≥-1), osteopenia (between -1 and -2.5), and osteoporosis (≤-2.5).

RESULTS

We included 228 lymphoma survivors, of whom 62% were males. The median age at survey was 56 years, and median observation time from HDT-ASCT was eight years. Among males, Z-scores were lower at the left femoral neck and higher at the ultra-distal (UD) radius and whole body compared to the Lunar reference database. In females, Z-scores were lower at UD radius and one-third (33%) radius and higher at the whole body. Using a classification based on Z-scores at the lumbar spine, femoral neck, and hip in combination, 25% of males and 16% of females had Z-scores <-1 and >-2, while 8% and 6% had Z-scores ≤-2. According to T-scores, 35% of males and 41% of females had osteopenia, while 8% and 13% had osteoporosis, respectively.

CONCLUSION

BMD was close to normal for age in this population of long-term lymphoma survivors treated with HDT-ASCT.

Osteopenia and osteoporosis among 16-65 year old women attending outpatient clinics

Women living in developing countries are more prone to osteoporotic fractures than women in developed countries. The objectives of this study were to estimate the burden of osteopenia and osteoporosis and examine their correlates among Bangladeshi women. This cross-sectional study consisted of 500 women aged 16-65 years attending gynecology and family planning clinics of a tertiary hospital which cares urban/suburban low income population in Dhaka, Bangladesh. Bone mineral density (BMD) was measured at the lumbar spine and femoral neck using dual X-ray absorptiometry. We calculated T scores based on sex-matched reference data from Caucasian women provided by the manufacturer. Osteoporosis was defined as a BMD at either site more than 2.5 standard deviations (SD) below the young healthy adult woman mean while the osteopenia was defined as a BMD between 1 and 2.5 SD below the mean as suggested by the World Health Organization. Separate multivariable logistic regression analysis was used to examine the correlates of osteopenia/osteoporosis among 16-45 and 46-65 year old women. Overall, 43.6 and 5.5 % of 16-45 year old women, and 40.7 and 41.8 % of 46-65 year old women had osteopenia and osteoporosis based on T scores either of the two sites (lumbar spine or femoral neck), respectively. Body mass index was negatively associated with osteopenia/osteoporosis at both lumbar spine and femoral neck, while age was positively associated. The burden of osteopenia/osteoporosis is very high in Bangladeshi women which warrants appropriate interventional strategies to minimize future fractures and reduce related social and economic burden of the society.

Bone mineral density: reference values and correlates for Bangladeshi women aged 16-65 years

BACKGROUND

Studies examining the reference values of bone mineral density (BMD) and their patterns at different ages are largely based on data generated from developed countries. The objective of this study was to estimate reference values of BMD, along with their correlates, for women living in urban and suburban areas of Bangladesh.

METHODS

Dual-energy X-ray absorptiometry scans were performed on 500 women 16-65 years of age. Reference values at the lumbar spine (LS) and femoral neck (FN) were estimated after adjusting for height and weight. In addition, multiple linear regression analysis was used to examine correlates of BMD at the LS and FN.

RESULTS

Mean BMD was highest at the LS and FN in women 16-19 (1.001-1.007 g/cm(2)) and 16-22 years of age (0.880-0.888 g/cm(2)), respectively, and gradually declined with increasing age thereafter. BMD decreased at an annual rate of 0.0027 g/cm(2) at the LS and 0.0046 g/cm(2) at the FN among women aged 16-45 years. For women 46-65 years of age, the respective figures were 0.0073 and 0.0083 g/cm(2). In both age groups, body weight was positively associated with BMD at both sites, and with height only at the LS. In addition, years of pill use was positively associated with BMD at the LS among women aged 16-45 years. BMD levels at both sites began to decline during the early twenties among Bangladeshi women.

CONCLUSIONS

Age-specific BMD data generated in this study could be useful for interpreting bone densitometry data among women in Bangladesh and other South Asian countries.

The Tromsø Study: Fit Futures: a study of Norwegian adolescents' lifestyle and bone health

Bone mass achievement predicts later fracture risk. This population-based study describes bone mineral density (BMD) levels and associated factors in Norwegian adolescents. Compared with international reference ranges, BMD levels appear higher and physical activity levels are positively associated with BMD.

PURPOSE

Norway has one of the highest reported incidences of osteoporotic fractures. Maximisation of peak bone mass may prevent later fractures. This population-based study compared BMD levels of Norwegian adolescents with international reference ranges and explored associated factors.

METHODS

All first-year upper-secondary school students, aged 15-19 years in the Tromsø region were invited to the Fit Futures study in 2010-2011. Over 90 % of the invited participants attended, 508 girls and 530 boys. BMD was measured at total hip, femoral neck and total body by dual X-ray absorptiometry. Lifestyle variables were collected by self-administered questionnaires and interviews. All analyses were performed sex stratified, using linear regression models.

RESULTS

In girls, mean BMD (SD) was 1.060 g/cm(2) (0.124), 1.066 g/cm(2) (0.123) and 1.142 g/cm(2) (0.077) at the total hip, femoral neck and total body, respectively. In boys, corresponding values were 1.116 (0.147), 1.103 (0.150) and 1.182 (0.097), with significant higher values than the Lunar pediatric reference at 16 years of age. In girls, height and self-reported intensive physical activity of more than 4 h a week and early sexual maturation were positively associated with BMD at both femoral sites (p < 0.047). Among boys age, height, body mass index, physical activity and alcohol intake were positively (p < 0.038), whereas early stages of sexual maturation and smoking was negatively (p < 0.047) related to BMD.

CONCLUSIONS

Despite the heavy fracture burden, Norwegian adolescents' BMD levels are higher than age-matched Caucasians. Physical activity is associated with 1 SD increased BMD levels in those involved in competition or hard training.

Racial differences in the association between body fat distribution and lipid profiles among reproductive-age women

AIM

The aim of this study was to examine the racial and ethnic differences in the relationship between body fat distribution variables and serum lipid profiles.

METHODS

Secondary data analyses were conducted on 708 healthy women (204 blacks, 247 whites and 257 Hispanics), aged 16-33 years, seen in an outpatients clinic for contraception. Pearson correlation and multivariable linear regression techniques were used to identify racial/ethnic differences in the relationship between lipid profiles and body fat after adjusting for lean mass as well as demographic and lifestyle variables.

RESULTS

All body fat distribution variables were significantly associated with total cholesterol (TC) (r=0.14 to 0.26), triglycerides (TG) (r=0.13 to 0.46), HDL cholesterol (r=-0.13 to -0.34), cholesterol-to-HDL ratio (r=0.20 to 0.50) and atherogenic index of plasma (AIP) (r=0.16 to 0.49). Significant racial/ethnic differences were observed in many associations. After adjusting for lean mass, and other demographic and lifestyle factors, the study showed that black women demonstrated significantly weaker associations than their white and Hispanic counterparts using multivariable linear regression procedures.

CONCLUSION

The relationship between lipid profiles and body fat distribution variables varies by race/ethnicity in reproductive-age women. A better understanding of these racial/ethnic differences has important implications for clinical and public-health efforts in targeting the prevention of cardiovascular disease (CVD).

Racial differences in body fat distribution among reproductive-aged women

We examined the influence of race/ethnicity on body fat distribution for a given body mass index (BMI) among reproductive-aged women. Body weight, height, and body fat distribution were measured with a digital scale, wall-mounted stadiometer, and dual-energy x-ray absorptiometry, respectively, on 708 healthy black, white, and Hispanic women 16 to 33 years of age. Multiple linear regression was used to model the relationship between race/ethnicity and different body fat distribution variables after adjusting for BMI, age at menarche, and demographic and lifestyle variables. For a given BMI, white women had the highest total fat mass (FM(total)), trunk fat mass (FM(trunk)), and leg fat mass (FM(leg)), whereas Hispanic women had the highest percentage of FM(trunk) (%FM(trunk)) and trunk-to-limb fat mass ratio (FMR(trunk-to-limb)). Conversely, black women had the lowest FM(total), FM(trunk), percentage body fat mass (%FM), %FM(trunk), and FMR(trunk-to-limb), and the highest percentage of FM(leg). The %FM was similar in whites and Hispanics and lower in blacks. The race x BMI interactions were significant for almost all of the body fat distribution variables. Increasing in differences with increasing BMI were apparent between blacks and whites in FM(trunk), %FM(trunk), FMR(trunk-to-limb), %FM(leg), and %FM, and between blacks and Hispanics in FM(trunk), %FM(trunk), FMR(trunk-to-limb), and FM(leg). In summary, the distribution of body fat for a given BMI differs by race among reproductive-aged women. These findings raise questions regarding universally applied BMI-based guidelines for obesity and have implications for patient education regarding individual risk factors for cardiovascular disease and metabolic complications.

Racial difference in the correlates of bone mineral content/density and age at peak among reproductive-aged women

SUMMARY

Racial/ethnic differences were observed in age at peak bone density and their correlates, with whites peaking at least 5 years earlier at the femoral neck than black and Hispanic women. Race-specific standards generated in this study could be useful when interpreting bone densitometry data in young women.

INTRODUCTION

The influence of race/ethnicity on bone measurements has not been widely examined. This study identifies age and amount of bone accumulated at peak density and their correlates by race/ethnicity.

METHODS

Bone mineral content (BMC) and bone mineral density (BMD) of the spine and femoral neck were measured by dual X-ray absorptiometry in 708 white, black, and Hispanic reproductive-aged women. Race-specific nonlinear models were used to describe the relationship between age and bone measurements, after adjusting for body weight and height. Log-transformed bone measurements were used to determine predictors based on multiple linear regression.

RESULTS

Predictors, which were race and site specific, included age, age at menarche, body weight, height, months of depot medroxyprogesterone acetate use, weight-bearing exercise, and alcohol use. Women of all races gained BMC and BMD at the spine up to 30-33 years of age. BMC and BMD of the femoral neck peaked among white women earlier (<or=16 years) than among blacks (BMC 22 years; BMD 21 years) and Hispanics (BMC 29 years; BMD 20 years).

CONCLUSION

Age at peak bone mass and its correlates differ by race/ethnicity. Race-specific standards generated in this study could be useful when interpreting bone densitometry data in young women.

Effects of depot medroxyprogesterone acetate and 20-microgram oral contraceptives on bone mineral density

OBJECTIVE

Hormonal contraceptives may adversely affect bone mineral density. However, racial differences and the reversibility of these changes are poorly understood. This study measured bone mineral density changes during hormonal contraceptive use and after discontinuation in a triethnic population.

METHODS

Bone mineral density was measured every 6 months for up to 3 years in 703 white, African-American, and Hispanic women using oral contraceptives (OCPs), depot medroxyprogesterone acetate (DMPA), or nonhormonal contraceptives, and in 68 DMPA discontinuers for up to 2 additional years. Mixed-model regression analyses were used to estimate the percentage change in bone mineral density for each contraceptive method.

RESULTS

Over 3 years, DMPA and OCP users lost more bone mineral density than did nonhormonal contraceptive users (-3.7% and -0.5% compared with +1.9% at lumbar spine, and -5.2% and -1.3% compared with +0.6% at femoral neck, respectively). No differences were observed by race in bone mineral density changes that resulted from DMPA or OCP use. However, DMPA users aged 16-24 years lost more bone mineral density at the spine (4.2% compared with 3.2%, P=.006) and femoral neck (6.0% compared with 4.2%, P=.001) than those aged 25-33 years. After DMPA discontinuation, women who selected nonhormonal contraceptives gained bone mineral density (+4.9% at spine, +3.2% at femoral neck), whereas those who selected OCP recovered spinal (+2.3%) but not femoral neck bone mineral density (-0.7%).

CONCLUSION

Use of very-low-dose OCPs may result in a small amount of bone loss. Use of DMPA results in greater bone loss, but this is largely reversible at the spine. Use of very-low-dose OCPs after DMPA discontinuation may slow bone recovery.