What is the influence of weight change on forearm bone mineral density in peri- and postmenopausal women? The health study of Nord-Trondelag, Norway

Weight loss since early adulthood, later life risk of fracture hospitalizations, and bone mineral density: a prospective cohort study of 0.5 million Chinese adults

In a Chinese population from both urban and rural areas, weight loss of ≥ 5 kg from early adulthood to midlife was associated with a higher risk of hip fracture and lower BMD in later life.

INTRODUCTION

This study investigates the association of the long-term weight loss from young adulthood through the middle ages with the subsequent 10-year risk of hospitalized fracture and calcaneus bone mineral density (BMD).

METHODS

China Kadoorie Biobank (CKB) was established during 2004-2008 in ten areas across China. Weight at age 25 years was self-reported at baseline, and weight at baseline and resurvey was measured by the calibrated equipment. Outcomes were hospitalized fracture during follow-up and calcaneus BMD measured at resurvey. Analysis for fracture risk included 411,812 participants who were free of fracture in the last 5 years before baseline, cancer, or stroke at any time before baseline. Analysis for BMD included 21,453 participants who participated in the resurvey of 2013-2014 with the same exclusion criteria as above.

RESULTS

The mean age was 50.8 at baseline and 58.4 at resurvey. Median weight change from age 25 to baseline was 4.4 kg, with 20.7% losing weight and 58.5% gaining weight. During a median follow-up of 10.1 years, we documented 13,065 cases of first diagnosed fracture hospitalizations, including 1222 hip fracture. Compared with participants whose weight was stable (± 2.4 kg), the adjusted hazard ratios (95% CIs) for those with weight loss of ≥ 5.0 kg from age 25 to baseline was 1.39 (1.17 to 1.66) for hip fracture. Weight loss was not associated with fracture risk at other sites. Those with weight loss from age 25 to resurvey had the lowest BMD measures, with β (95% CIs) of - 4.52 (- 5.08 to - 3.96) for broadband ultrasound attenuation (BUA), - 4.83 (- 6.98, - 2.67) for speed of sound (SOS), and - 4.36 (- 5.22, - 3.49) for stiffness index (SI).

CONCLUSIONS

Weight loss from early adulthood to midlife was associated with a higher risk of hip fracture and lower BMD in later life.

Less influence of body mass index on bone mineral density of radius as compared to proximal femur: Possible role in the diagnosis of osteoporosis

It has been shown that body mass index (BMI) and obesity may affect the mineral density of bones, regionally on weight-bearing bones or systemically through hormones and cytokines. The objective of this study was to evaluate the effect of BMI on bone mineral density (BMD) of the radius. In this cross-sectional study, 260 patients, 233 postmenopausal women and 27 men over 50, were included who underwent a bone densitometry scanning using dual-energy X-ray absorptiometry after obtaining an informed consent. The scanning was performed in three areas (i.e., spine, proximal femur, and radius), then densitometric data (BMD, T- and Z-score) were extracted. Regression analysis was performed to evaluate the effect of independent variables of age, gender, and BMI on the BMD of the above regions. By grouping the patients in two categories (BMI <25 as normal or underweight and BMI >25 as overweight and obese), the discordance in the diagnosis following the inclusion of radius into interpretation (diagnosis based on 2 vs. 3 areas), was assessed by an agreement test. The study is approved by the ethics committee of the university. Of 260 participants in the present study, mean and standard deviation for age were 61.48 ± 8.95 for all patients, 65.81 ± 10.59 for male and 60.98 ± 8.62 for women. An increasing effect of BMI was found to be statistically significant in weight-bearing areas (total femur and femoral neck) and BMI increase was not associated with increased BMD of radius. An agreement test between two diagnoses is used that showed a discordance of 28.5% in diagnosis (diagnosis based on 2 vs. 3 areas) with a kappa coefficient of 0.547 (P = 0.001). In total, 25.4% was minor discordance and 3.1% was major discordance. Based on the results of this study, it is concluded that the BMI is not associated with increased BMD in bones that are not weight bearing, such as radius. Therefore, it may be preferred to include the densitometric data of radius into the diagnosis.

The effects of weight loss approaches on bone mineral density in adults: a systematic review and meta-analysis of randomized controlled trials

We assessed the impact of weight loss strategies including calorie restriction and exercise training on BMD in adults using a systematic review of randomized controlled trials. Weight reduction results in reduced BMD at the hip, but has less effect on the spine. Both calorie restriction and a combination of calorie restriction and exercise result in a decrease in hip bone density, whereas weight loss response to exercise training without dietary restriction leads to increased hip BMD.

INTRODUCTION

Findings are not consistent on the effect of weight loss on bone mineral density (BMD). We conducted a systematic review on the randomized controlled trials to assess the effect of weight loss strategies, including calorie restriction and exercise programs on BMD in adults.

METHODS

A structured and comprehensive search of MEDLINE and EMBASE databases was undertaken up to March 2016. Study-specific mean differences (MD) were pooled using a random-effects model. Subgroup analysis and meta-regression were used to find possible sources of between-study heterogeneity.

RESULTS

Thirty-two randomized controlled trials met predetermined inclusion criteria. The meta-analysis revealed no significant difference on total BMD (MD 0.007, 95 % CI -0.020-0.034, p = 0.608). In contrast, the pooled data of studies showed a significant effect of weight loss on hip BMD (MD -0.008, 95 % CI -0.09 to -0.006 g/cm(2), p < 0.001) and also lumbar spine BMD (MD -0.018 g/cm(2), 95 % CI -0.019 to -0.017, p < 0.001). BMD in the hip site decreased after more than 4 months, especially in those who were obese. Moreover, calorie restriction interventions longer than 13 months showed a significant decreased in lumbar spine BMD.

CONCLUSION

Weight loss led to significant decreases at the hip and lumbar spine BMD but not at the total. Weight loss response following calorie restriction resulted in a decrease in hip and lumbar spine bone density especially more than 1 year; whereas an exercise-induced weight loss did not.

Underweight Young Women Without Later Weight Gain Are at High Risk for Osteopenia After Midlife: The KOBE Study

Background

Although underweight young women are targets for interventions to prevent low bone mineral density (BMD), the relationship between change in body mass index (BMI) from youth to older age and BMD has not been widely investigated in community dwellers.

Methods

In 749 healthy Japanese women aged 40–74 years, BMD was measured by quantitative ultrasound and anthropometric measurements, and BMI was calculated from body weight and height. The BMI of participants at age 20 years was estimated by self-reported body weight and their present height. They were classified into four groups according to the presence of underweight (BMI <18.5 kg/m²) at 20 and/or at present. Logistic regression models were used to estimate multivariate-adjusted odds ratios (ORs) of the presence of underweight at 20 and/or at present for osteopenia (BMD T score <−1 standard deviations) compared with participants with BMI ≥18.5 kg/m² both at 20 and at present.

Results

The participants who were underweight both at 20 and at present had a higher OR for osteopenia compared with those with BMI ≥18.5 kg/m² at 20 and at present (OR 3.94; 95% confidence interval [CI], 1.97–7.89). Those underweight only at present also had significantly increased OR of developing osteopenia (OR 2.95; 95% CI, 1.67–5.24). The OR of those underweight only at 20 was 0.87 (95% CI, 0.51–1.48).

Conclusions

Current underweight was associated with increased risk for osteopenia among Japanese women, especially in those who were underweight both at 20 and at present. To prevent low BMD in the future, maintaining appropriate body weight might be effective for young underweight women.

Excess mortality after hip fracture among elderly women in Norway. The HUNT study

We wanted to study mortality after hip fractures among elderly women in Norway. We found that excess mortality was highest short time after hip fracture, but persisted for several years after the fracture. The excess mortality was not explained by pre-fracture medical conditions.

INTRODUCTION

The purpose of the present study was to investigate short and long term mortality after hip fracture, and to evaluate how comorbidity, bone mineral density, and lifestyle factors affect the survival after hip fractures.

METHODS

The study cohort emerges from a population-based health survey in the county of Nord-Trøndelag, Norway. Women aged 65 or more at participation at the health survey who sustained a hip fracture after attending the health survey are cases in this study (n = 781). A comparison cohort was constructed based on participants at HUNT 2 with no history of hip fractures (n = 3, 142). Kaplan-Meier survival curves were used to evaluate crude survival, and Cox regression analyses were used to study age-adjusted hazard ratios for mortality and for multivariable analyses involving relevant covariates.

RESULTS

Mean length of follow-up after fracture was 2.8 years. Within the first 3 months of follow-up, 78 (10.0%) of the hip fracture patients died, compared to only 39 (1.7%) in the control group. HR for mortality 3 months after hip fracture was 6.5 (95% CI 4.2-9.6). For the entire follow-up period women who sustained a hip fracture had an HR for mortality of 1.9 (95% CI 1.6-2.3), compared with women without a hip fracture.

CONCLUSIONS

We found that elderly women who sustained a hip fracture had increased mortality risk. The excess mortality was highest short time after the fracture, but persisted for several years after the fracture, and was not explained by pre-fracture medical conditions.

The role of fat and lean mass in bone loss in older men: findings from the CHAMP study

PURPOSE

Weight loss is associated with bone loss; however, it is unclear whether loss of fat or loss of lean body mass plays the key role in this relationship. The aim of this longitudinal analysis was to clarify the relationship between hip BMD, hip BMC and whole body BMC with changes in fat and lean tissue mass in older men.

METHODS

The Concord Health and Aging in Men Project (CHAMP) is a population-based study in Sydney, Australia, involving 1705 men aged 70-97 years. Bone mineral density (BMD) of the total hip, and bone mineral content (BMC) of the hip and whole body (WB), lean mass and fat mass were measured with Dual X-ray Absorptiometry (DXA). Multivariate linear regression models were used to assess relationships.

RESULTS

Over 2.2 years of follow-up, 368(33%) men lost at least 2% of their body weight, which included a mean loss of 0.8 kg/year of lean body mass and 0.9 kg/year of fat body mass. Fat loss was strongly associated with BMD loss in men who lost weight. As a group, weight losers lost 1.0% of hip BMD annually compared to 0.2% in men who gained weight, with each kilo of fat loss associated with 0.6%/year hip BMD loss (p<0.0001). Lean mass was not associated with hip BMD loss in weight losers, however, lean mass change was associated with BMD change in men who gained weight (0.3% hip BMD increase per kilo increase of lean mass p<0.01).

CONCLUSION

Maintaining body weight is important for bone health in elderly men. Body fat plays an important role in this relationship, which may reflect the additional metabolic function of adipose tissue.

Adiponectin and peak bone mass in men: a cross-sectional, population-based study

Adiponectin, a protein classically known to be secreted by adipocytes, is also secreted by bone-forming cells. Results of previous studies have been contradictory as to whether serum adiponectin and bone mineral density (BMD) are associated. The aim of this study was to investigate a possible association between serum adiponectin and BMD in young, healthy men at a time of peak bone mass. BMD in the femoral neck, total hip, and lumbar spine were measured in this population-based cross-sectional study of 700 men aged 20-29 years participating in the Odense Androgen Study. Magnetic resonance imaging of femoral cortical thickness and bone marrow size was performed in a subsample of 363 participants. The associations between serum adiponectin and various bone measures were investigated by means of regression analyses with adjustment for potential confounding variables. An inverse association was found between serum adiponectin and total hip BMD and a direct between adiponectin and femoral bone marrow size (r = -0.092; P = 0.036 and r = 0.164; P = 0.003, respectively). Femoral muscle size may, at least in part, explain the association between adiponectin and total hip BMD. Serum adiponectin was inversely associated with total hip BMD in men at the time of peak bone mass, but this association may be explained by factors related to muscle size and function. The observed association between adiponectin and femoral bone marrow size was retained even after adjustment for potential covariates.

Incidence and seasonal variation in hip fracture incidence among elderly women in Norway. The HUNT Study

There is a substantial variation in hip fracture incidence between populations. The Scandinavian countries have the highest incidence of hip fractures worldwide, and latitude and seasonal variation have been discussed as possible reasons for the high fracture incidences. The purpose of this study was to investigate time dependent and seasonal variation of hip fractures in a population based cohort of women aged 65+ residing in a rural county in Norway and followed for 9.3 years. Information at baseline was collected as part of The Nord-Trøndelag Health Study (HUNT) during 1995-97, and 8362 women with no previous hip fracture and with a mean age of 74.3 years were included in the study. All hip fractures occurring after inclusion in the health study were registered (mean follow-up: 9.3 years) by medical journals and x-ray reports. A total of 5661 of the women had their forearm bone mineral density (BMD) measured by single energy x-ray bone densitometers (SXA) as part of HUNT. In total, 782 women sustained a first hip fracture during follow-up, and the overall hip fracture incidence rate per 1000 person-years was 13.1 (95 % CI: 12.2-14.1). The hip fracture incidence increased exponentially by age from 2.1 (95% CI: 1.2-3.8) in the age group 65-69 years to 49.7 (95% CI: 41.2-59.8) among the women aged 90+, respectively. In age-stratified analyses no changes in the incidence of hip fractures were observed during the nine years of follow up. The occurrence of fractures varied by season of the year, characterized by higher fracture rates during the winter months. In conclusion, the hip fracture rates in this population of elderly women are highest in the winter months. There was, however, no indication of an increasing hip fracture incidence in this rural area. Compared to similar studies from more urban areas in Norway, the hip fracture rates in this population seem somewhat lower.

Past and current weight change and forearm bone loss in middle-aged women: the Nord-Trøndelag Health Study, Norway

OBJECTIVE

The aim of this study was to investigate the association between bone loss and weight change before and concurrently to the assessment of forearm bone loss over 4.6 years in a population-based cohort of middle-aged women followed for more than 15 years.

METHODS

Among 8,856 women aged 45 to 60 years attending the first Nord-Trøndelag Health Study study, Norway (1984-1986), a 35% random sample was invited for forearm densitometry at Nord-Trøndelag Health Study 2 (1995-1997), and 2,188 women (78%) attended. After an average period of 4.6 years, they were subsequently invited for follow-up densitometry in 2001, and 1,421 women (67.8%) met. Weight and height were measured on all three occasions.

RESULTS

During the total period of observation since baseline (15.5 y), the mean weight had increased by 3.4 kg, mostly in the youngest women. Weight loss had an accelerating and weight gain a decelerating effect on bone loss, and this was observed both for weight change occurring before the bone mineral density follow-up and for concurrent weight change. The relationship between prior weight gain or loss and bone loss seemed to persist, independent of the weight change observed during the period of bone loss assessment.

CONCLUSIONS

Despite no mechanical impact of body weight on the forearm, weight loss in midlife women seems to be associated with a long-lasting negative effect on bone and vice versa for weight gain. This is presumably explained by humoral factors.

Weight loss and distal forearm fractures in postmenopausal women: the Nord-Trøndelag health study, Norway

SUMMARY

Weight loss is a risk factor for hip fractures, but few studies have evaluated the effect of weight loss on distal forearm fracture risk. In this longitudinal study including 7,871 postmenopausal women, weight loss of 5% or more was associated with an increased risk of distal forearm fractures.

INTRODUCTION

Weight loss is an established risk factor for hip fractures, but little is known about weight loss and distal forearm fractures risk.

METHODS

The study included 7,871 women aged 65 years or more in the Nord-Trøndelag health study (HUNT) in 1994-1995 (HUNT II) who also had their height and weight measured in 1984-1986 (HUNT I). Forearm bone mineral density (BMD) by single energy x-ray absorptiometry was available for 5,688 women (HUNT II). Fractures sustained after HUNT II were registered during an average of 5.8 years.

RESULTS

A total of 536 women sustained a distal forearm fracture. After adjustments for age and body mass index (BMI) at HUNT I, women who lost > or =5% of their weight between HUNT I and HUNT II had a relative risk of fractures of 1.33 (95% confidence interval: 1.09, 1.62) compared with the rest of the women. The higher risk of forearm fracture among women with weight loss was at least partially explained by their lower forearm BMD.

CONCLUSION

Weight loss of 5% or more was associated with a 33% increased risk of distal forearm fractures.

Circulating adiponectin represents a biomarker of the association between adiposity and bone mineral density

An association exists between adiposity, insulin resistance, and osteoporosis; however, the mechanism of this relationship remains enigmatic. We aimed to determine whether the insulin resistance index (HOMA-IR), serum adiponectin, or leptin levels are associated with bone mineral density (BMD). A cross-sectional, observational study was designed. Eighty-four postmenopausal ambulant women [52.5 (50.0-58.0) years; body mass index (BMI): 29.4 (25.9-33.8) kg/m(2)] referred for osteoporosis screening were enrolled. Anthropometric measures, fasting serum adiponectin and leptin levels, and the HOMA-IR were determined. The relationships between these variables and lumbar, hip, and forearm BMD measured by dual-energy X-ray absorptiometry (DXA) were analyzed. Considering all 84 participants, the HOMA-IR index was 1.82 (1.17-2.86), serum adiponectin was 13.25 (10.49-16.88) microg/ml, and serum leptin was 19.26 (14.94-24.90) ng/ml. BMI, waist circumference, and leptin positively correlated with hip and lumbar BMD, whereas adiponectin negatively correlated. Multivariate analysis confirmed an inverse relation between serum adiponectin level and femoral neck and lumbar BMD measurements. In total hip and forearm areas, there was no independent association of adipocytokines with BMD measurements. Instead, waist circumference was independently associated with BMD measurements. In conclusion, adiponectin may represent a biomarker in the relationship between visceral fat mass and BMD. However, this association is probably confounded by the specific body composition parameters (i.e., waist circumference, BMI) in postmenopausal women.

Effect of body fat stores on total and regional bone mineral density in perimenopausal Chinese women

Accumulation of body fat is known to be beneficial to bone mass through increased body weight. However, not all the skeleton is loaded by body weight. Therefore, we assume that fat stores would exert different effects on bone mass at different skeletal sites. In this study, 84 perimenopausal Chinese women were recruited. Using dual-energy X-ray absorptiometry, total body fat mass (TBFM), total body lean mass (TBLM), percent body fat (PBF), and total body and regional bone mineral density (BMD) were measured. Correlation analysis indicated that PBF correlated negatively with BMD at ribs and both arms (all P < 0.05). After adjusting for TBLM, PBF had a significantly negative correlation with BMD at head, ribs, both arms, and whole body (all P < 0.05). With adjustment for body weight and height, a significantly negative correlation between PBF and BMD was present, not only at ribs and arms but also at legs and whole body (all P < 0.05, except right leg, at P = 0.094). There was a significantly positive correlation between body weight and leg BMD (all P < 0.001). Body weight was positively correlated with TBFM (r (2) = 0.783, P < 0.001) and TBLM (r (2) = 0.770, P < 0.001). Based on the results, we conclude that increased body fat stores would exert a detrimental effect on BMD, but this effect is more prominent on non-weight-bearing bone. On weight-bearing bone, the detrimental effect of increased body fat could be offset or outweighed by the beneficial effect of increased body weight.

Differences in precision in bone mineral density measured by SXA and DXA: the NOREPOS study

The aims were to compare the precision (reliability) in single X-ray (SXA) and dual X-ray (DXA) absorptiometry, and to compare smallest detectable difference (SDD). An additional aim was to examine determinants for precision in bone mineral density (BMD). BMD was measured by SXA (DTX-100, Osteometer) in the forearm and by DXA (Lunar Expert) in the forearm and in the hip. Two measurements were performed at each site/method, and 195 of 207 participants had complete datasets. Participants were aged 47-49 and 71-74 years. The precision was estimated by Root Mean Square Standard Deviation (RMS SD) with 95% Confidence Interval (95%CI) and the corresponding coefficients of variation (CV%). Determinants (age, gender, BMD) were analysed by multiple linear regression with log (SD) and log (CV) as dependent variables. RMS SD tended to be largest in older women and in those with low BMD. RMS SD for SXA and DXA forearm was 4.6 (4.2-5.1) and 6.8 (6.1-7.4) and the corresponding CVs 1.0% and 1.4%. RMS SD for DXA hip was 11.0 (9.9-12.0) with CV 1.2%. To detect a 3% change in BMD one would need two repeated measurements by DXA in the distal forearm at each of two consultations, but only one measurement by SXA in the distal forearm and also only one measurement by DXA in the hip. Precision differed by type of densitometer affecting the number of repeated measurements needed to detect a given BMD difference.