Forearm bone mineral density in an unselected population of 2,779 men and women--the HUNT Study, Norway

Bone mineral density and risk of cardiovascular disease in men and women: the HUNT study

The association between bone mineral density (BMD) and cardiovascular disease (CVD) is not fully understood. We evaluated BMD as a risk factor for cardiovascular disease and specifically atrial fibrillation (AF), acute myocardial infarction (AMI), ischemic (IS) and hemorrhagic stroke (HS) and heart failure (HF) in men and women. This prospective population cohort utilized data on 22 857 adults from the second and third surveys of the HUNT Study in Norway free from CVD at baseline. BMD was measured using single and dual-energy X-ray absorptiometry in the non-dominant distal forearm and T-score was calculated. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated from adjusted cox proportional hazards models. The analyses were sex-stratified, and models were adjusted for age, age-squared, BMI, physical activity, smoking status, alcohol use, and education level. Additionally, in women, we adjusted for estrogen use and postmenopause. During a mean follow-up of 13.6 ± 5.7 years, 2 928 individuals (12.8%) developed fatal or non-fatal CVD, 1 020 AF (4.5%), 1 172 AMI (5.1%), 1 389 IS (6.1%), 264 HS (1.1%), and 464 HF (2.0%). For every 1 unit decrease in BMD T-score the HR for any CVD was 1.01 (95% CI 0.98 to 1.04) in women and 0.99 (95% CI 0.94 to 1.03) in men. Point estimates for the four cardiovascular outcomes ranged from slightly protective (HR 0.95 for AF in men) to slightly deleterious (HR 1.12 for HS in men). We found no evidence of association of lower distal forearm BMD with CVD, AF, AMI, IS, HS, and HF.

Cohort profile: Norwegian Epidemiologic Osteoporosis Studies (NOREPOS)

AIMS

This paper describes the history, purpose, data collection and contributions in the research collaboration Norwegian Osteoporosis Epidemiologic Studies (NOREPOS).

METHODS

NOREPOS encompasses almost 85,000 bone mineral density measurements within Cohort of Norway and data on almost 140,000 hip fractures in Norway 1994-2008. Included are anthropometric measurements, blood pressure, lipids and glucose, and 50 standard questions on sociodemographic factors, diseases and risk factors. Blood samples/DNA are stored. The main research question posed in NOREPOS is why hip fracture rates in Norway are the highest in the world. Data on hip fractures 2009-2013 will be added in 2014.

RESULTS

Main findings include: Every hour a Norwegian suffers a hip fracture; hip fracture incidence rates declined after 1999; only 16% of patients used anti-osteoporosis drugs 1 year after hip fracture; 25% of patients died within 1 year after the fracture; 12% suffered a new hip fracture within 10 years; rural dwellers had lower hip and forearm fracture incidence than city dwellers; magnesium in tap water may be protective whereas bacterial contamination, cadmium and lead may be harmful to bone health; low serum vitamin D and E levels were associated with higher hip fracture risk; vitamin A was not associated with fracture risk; and abdominal obesity increased the risk of hip fracture when BMI was accounted for.

CONCLUSIONS

NOREPOS encompasses a unique source of information for aetiological research, genetic studies as well as for biomarkers of osteoporosis and fractures. Because of the increasing number of elderly people in Europe, hip fractures will continue to pose an international public health and health care challenge.

Indications of DXA in women younger than 65 yr and men younger than 70 yr: the 2013 Official Positions

Dual-energy X-ray absorptiometry (DXA) is the method of choice to assess fracture risk for women 65 yr and older and men 70 yr and older. The 2007 International Society for Clinical Densitometry Official Positions had developed guidelines for assessing bone density in younger women during and after the menopausal transition and in men 50-69 yr and the 2008 National Osteoporosis Foundation (NOF) guidelines recommended testing in postmenopausal women younger than 65 yr and men 50-69 yr only in the presence of clinical risk factors. The purpose of the 2013 DXA Task Force was to reassess the NOF guidelines for ordering DXA in postmenopausal women younger than 65 yr and men 50-69 yr. The Task Force reviewed the literature published since the 2007 Position Development Conference and 2008 NOF, reviewing clinical decision rules such as the Osteoporosis Screening Tool and FRAX and sought to keep recommendations simple to remember and implement. Based on this assessment, the NOF guidelines were endorsed; DXA was recommended in those postmenopausal women younger than 65 yr and men 50-69 yr only in the presence of clinical risk factors for low bone mass, such as low body weight, prior fracture, high-risk medication use, or a disease or condition associated with bone loss.

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.

Forearm bone mineral density varies as a function of adiposity in inuit women 40-90 years of age during the vitamin D-synthesizing period

Aging Inuit women are at increased risk for low vitamin D status due to habitation at higher latitudes, darker skin, and ongoing nutrition transition. Lower serum 25-hydroxyvitamin D (25[OH]D) concentration and higher risk of fracture have been separately reported in Inuit women, with particular relevance to postmenopausal women. We evaluated vitamin D status, forearm bone mineral density (fBMD), and nutrition in Inuit women ≥40 years. Women (n = 568) were randomly selected to participate in the 2007-2008 International Polar Year Inuit Health Survey from 36 Arctic communities. fBMD was measured using peripheral dual-energy X-ray absorptiometry. Dietary intakes were derived from 24 h recall and food-frequency questionnaires. Fasting serum 25(OH)D, parathyroid hormone, and osteocalcin (OC) were measured using a LIAISON(®) automated analyzer. The weighted prevalence of women having 25(OH)D concentration below 37.5, 50, and 75 nmol/L was 7.2 %, 17.6 %, and 48.6 %, respectively, with older women having better status. The dietary density of most nutrients increased with age, as did traditional food intake. fBMD was low in 3 (1.4 %) premenopausal (Z score < -2) and 107 (29.6 %) postmenopausal (T score < -1.5) women. Regression revealed that either weight, body mass index, or percent body fat significantly predicted fBMD in premenopausal women, in addition to age and OC in postmenopausal women. Women ≥50 years have higher vitamin D status and more nutrient-dense diets than women 40-49 years. While measures of adiposity predicted fBMD in all women, additional predictors after menopause included age and bone turnover.

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.

Peak bone mineral density of physically active healthy Indian men with adequate nutrition and no known current constraints to bone mineralization

We undertook this study to characterize peak bone density and evaluate its determinants in a healthy cohort of young adult male paramilitary personnel. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry in 473 healthy men aged 21-40 yr. The effect of anthropometry and biochemical parameters on BMD was determined. Mean BMD values of L1-L4, forearm, total hip, and femoral neck were 1.170+/-0.137, 0.755+/-0.089, 1.129+/-0.130, and 1.115+/-0.133 g/cm(2), respectively. BMD values for 31- to 40-yr age group were lower than those of 20- to 30-yr age group except for forearm, which was higher in the former. Significant positive correlation was observed between height, weight, and body mass index with BMD. On multivariate regression analysis, weight was the most consistent contributor to variance in the BMD. Compared with age-matched US males, BMD of total hip and femoral neck were higher for Indian paramilitary personnel by 3.58% and 4.2%, whereas lumbar spine BMD was lower by 4.1%. In conclusion, peak BMD in healthy Indian males was achieved by 30 yr of age at lumbar spine and hip, with weight being the most consistent contributor to variance in BMD. Peak BMD in this population was comparable to that reported in white US males.

Effects of the sample size of reference population on determining BMD reference curve and peak BMD and diagnosing osteoporosis

Establishing reference databases generally requires a large sample size to achieve reliable results. Our study revealed that the varying sample size from hundreds to thousands of individuals has no decisive effect on the bone mineral density (BMD) reference curve, peak BMD, and diagnosing osteoporosis. It provides a reference point for determining the sample size while establishing local BMD reference databases.

INTRODUCTION

This study attempts to determine a suitable sample size for establishing bone mineral density (BMD) reference databases in a local laboratory.

METHODS

The total reference population consisted of 3,662 Chinese females aged 6-85 years. BMDs were measured with a dual-energy X-ray absorptiometry densitometer. The subjects were randomly divided into four different sample groups, that is, total number (Tn) = 3,662, 1/2n = 1,831, 1/4n = 916, and 1/8n = 458. We used the best regression model to determine BMD reference curve and peak BMD.

RESULTS

There was no significant difference in the full curves between the four sample groups at each skeletal site, although some discrepancy at the end of the curves was observed at the spine. Peak BMDs were very similar in the four sample groups. According to the Chinese diagnostic criteria (BMD >25% below the peak BMD as osteoporosis), no difference was observed in the osteoporosis detection rate using the reference values determined by the four different sample groups.

CONCLUSIONS

Varying the sample size from hundreds to thousands has no decisive effect on establishing BMD reference curve and determining peak BMD. It should be practical for determining the reference population while establishing local BMD databases.

Height loss, forearm bone density and bone loss in menopausal women: a 15-year prospective study. The Nord-Trøndelag Health Study, Norway

In a population-based cohort of 1,421 women 45-60 years old followed for 15.5 years, 71% of the women had lost height. Height loss was associated with low forearm bone density and increased bone loss, but high body weight and oestrogen therapy were protective factors. Increased height loss indicates a generalized state of bone loss.

INTRODUCTION

The degree of height loss and its association to forearm bone mineral density (BMD) and bone loss was investigated in a population-based cohort of middle-aged women followed for more than 15 years.

METHODS

Among 8,856 women aged 45-60 years attending the first HUNT Study, Norway (1984-86), a 35% random sample was invited to forearm densitometry 11.3 years later (HUNT 2, 1995-97), and 2,188 attended (78.3%). In 2001, 15.5 years since baseline, all were invited to follow-up densitometry and height measurement.

RESULTS

A total of 71.2% and 17.4% of the 1,421 women attending had lost >1 cm and >3 cm of height since baseline, respectively. Women aged >or= 64 years at HUNT 2 had a relative risk (RR) for height loss >3 cm of 3.1 (95% CI 2.2, 4.3) compared to women <64 years. A strong and negative association was found between height loss and forearm BMD, adjusted for time since menopause. A high rate of height loss was associated to increased forearm bone loss. High body weight, oestrogen treatment and good self-rated health were protective against height loss.

CONCLUSION

Height loss is frequent in middle-aged women, and increased height loss indicates a generalized state of bone loss.

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 in the elderly increases bone loss and the risk of fractures, especially at the hip and spine. The influence of weight change on non-weight-bearing parts of the skeleton is less well known. The purpose of this study was to investigate an association between weight change during the peri- and postmenopausal years and forearm bone mineral density (BMD). Among 8,856 women aged 45-60 years attending the first Health Study of Nord-Trøndelag, Norway (HUNT I, 1984-1986), a random sample of 2,795 women was invited to forearm densitometry (single x-ray absorptiometry technology) at HUNT II (1995-1997), after a mean period of 11.3 years. A total of 2,005 women (mean age: 65.1 years) were eligible. The mean weight had increased 3.4 kg; the gain was greater in the youngest women. A total of 382 women (19.1%) had lost and 1,331 women (66.3%) had gained weight. Weight change explained little of the BMD variance, 0.7% and 0.4% for weight loss and weight gain, respectively. Weight loss was an independent and statistically significant negative predictor of BMD, adjusted for body weight, age, age at menopause, smoking, and ovarian hormone treatment, particularly among women with a baseline body mass index greater than 25 kg/m2. No independent association between weight gain and forearm BMD was found.

The epidemiology of hospitalised wrist fractures in older people, New South Wales, Australia

The epidemiology and trends in wrist fracture admissions to public and private acute hospitals in New South Wales (NSW), Australia, between July 1993 and June 2003 were examined using routinely collected hospital separations statistics. During the study period, the number of hospital separations for wrist fractures increased by 71% in men, an average yearly increase of 6.5%, and by 43% in women, an average yearly increase of 3.9%. A modest, but significant, increase in age-specific and age-standardised hospitalisation rates for wrist fractures was also observed. Whilst the majority of wrist fractures were due to falls, the proportion of falls-related wrist fractures decreased significantly over time. This decrease was more pronounced in males and was accompanied by a rise in the proportion of wrist fractures resulting from high energy mechanisms such as transport, violence and machinery-related incidents. The difference in hospitalised wrist fracture rates between men and women could not be explained solely on the basis of the role played by osteoporosis, indicating the need for more research to improve our understanding of the underlying factors of this type of fracture in older people.

Important Determinants of Bone Strength

Osteoporosis is a systemic skeletal disorder characterized by compromised bone strength that predisposes individuals to increased fracture risk. Bone strength is determined by its material and structural properties. Bone mineral density (BMD) is a useful tool for diagnosis; however, this parameter provides information regarding only the quantity of mineral in bone, which is only one component of bone strength. Osteoporosis treatments have been shown to have beneficial effects on bone turnover, microarchitecture, and/or mineralization, all of which can help account for the reductions in fracture risk above and beyond changes in BMD. Newer noninvasive imaging methods are being developed that assess bone strength independent of BMD, and these methods should improve the assessment of fracture risk and response to treatment. These imaging methods are not currently available for routine clinical use, and therefore, clinicians need to continue for now to rely on surrogate markers of bone fragility, including BMD, prevalent fracture, and other important risk factors for fracture.

Quantitative ultrasound of the calcaneus in a Korean population: reference data and relationship to bone mineral density determined by peripheral dual X-ray absorptiometry

The aim of this study was to establish reference data for the quantitative ultrasound (QUS) of the calcaneus and for the bone mineral densities (BMD) of the calcaneus and distal forearm, and to evaluate the correlation between QUS parameters and BMD in a Korean population. We performed a cross-sectional study involving 3,053 subjects (1,225 men and 1,828 women). QUS was conducted on the calcaneus and was quantified as speed of sound (SOS, m/sec), broadband ultrasound attenuation (BUA, dB/MHz), and stiffness index. The BMD of the calcaneus and distal forearm were measured using dual X-ray absorptiometry. The peak mean values for the QUS parameters occurred in the 20 to 29-yr-old subjects of both sexes, with the exception of the BUA, which reached the highest values in women of 30-39 yr. For both sexes, the mean BMD of the calcaneus was highest in those 20-29 yr old and that of the distal forearm was highest in those 40-49 yr old. The correlations between the QUS and BMD results were found to be 0.41 to 0.73 in men and 0.51 to 0.76 in women. Theses data can serve as a reference values for both sexes in Korea.