Endogenous estradiol and risk of dementia in women and men: the Rotterdam Study

We determined whether higher endogenous estradiol levels were associated with lower risk of dementia in older men and women not using hormonal replacement therapy, using a case-cohort design within the Rotterdam Study, a population-based follow-up study on chronic diseases, including dementia, in 7983 subjects aged 55 years or older, and ongoing since 1990. The analyses were based on a random subcohort of 508 women and 438 men, and on 76 women and 53 men with incident dementia. Cox proportional hazards models with robustly estimated standard errors showed that in women higher levels of total estradiol were associated with higher risk of dementia (age-adjusted hazard ratio per standard deviation increase 1.38; 95% CI 1.04-1.84). Age-adjusted HR's of Alzheimer's disease and vascular dementia associated with higher levels of total estradiol (per SD increase) were 1.24 (95% CI 0.87-1.76) and 2.19 (95% CI 1.22-3.92), respectively. Similar results were observed for bioavailable estradiol. Additional adjustments for potential confounders did not change the results substantially. In men, no clear association was observed between estradiol levels and risk of dementia or its subtypes. The findings do not support the hypothesis that higher levels of endogenous estradiol reduce risk of dementia, neither in women nor in men.

Bone mineral density and the risk of breast cancer: the Rotterdam Study

Estrogens play an important role in the development of breast cancer, but studies on serum levels of estrogens have shown inconsistent results. Bone mineral density is considered to be a marker for lifetime estrogen exposure. Some studies have suggested that a higher bone mass is associated with an increase in breast cancer risk. We investigated the association between bone mineral density (BMD), as measured at the lumbar spine and femoral neck, and the risk of breast cancer in women age 55 or older in the Rotterdam Study, a population-based cohort study in the Netherlands. Information on baseline lumbar spine and femoral neck BMD, as measured by DEXA (Lunar DPX-L), and cancer incidence was available for 3,107 women. The Rotterdam Cancer Registry provided information on follow-up of incident cancer. After an average follow-up time of 6.5 years, 74 new cases of breast cancer occurred. Z-scores of lumbar spine and femoral neck BMD were divided into tertiles and risk estimates for breast cancer were computed by the Cox proportional hazards model, using the middle tertile as a reference. Breast cancer risk in the upper tertile of lumbar spine BMD was doubled compared to the reference after adjustment for age, body mass index, and age at menopause (hazards ratio = 2.1 [1.1-3.7]), whereas risk estimates for women in the lower tertile did not significantly differ from the reference (hazards ratio = 1.5 [0.8-2.9]). Women with either a low intertrochanteric or femoral neck BMD appeared to have a somewhat decreased breast cancer risk, although this was not statistically significant. The results of this study suggest that in elderly women an association between especially lumbar spine BMD and incident breast cancer exists. Stimulating effects of estrogen on both trabecular bone and mammary cells may be responsible.

A population-based study of the effect of the HFE C282Y and H63D mutations on iron metabolism

The C282Y and H63D mutations in the HFE gene are important causes of hemochromatosis. In the elderly, these mutations might be associated with increased morbidity because of the lifelong accumulation of iron. In a population-based sample of the elderly, we determined the value of genotyping for HFE mutations to screen for subclinical hemochromatosis. HFE genotype frequencies were determined in a random group of 2095 subjects (55 years and over). In this random group, we selected within the six genotype groups a total of 342 individuals and measured their serum transferrin saturation, iron and ferritin levels. We also estimated the heritability and parameters needed to evaluate screening, including the sensitivity, specificity, positive and negative predictive values (PPV, NPV) of HFE genotypes. Iron parameters were significantly increased in subjects homozygous, heterozygous or compound heterozygous. The effect of the mutations was more pronounced in men than in women. For the H63D mutation, an allele dose effect was observed. The HFE gene explained about 5% of the variability in serum iron indices. The PPV for hemochromatosis for the C282Y homozygous was 100% in men and 67% in women. The NPV of the wild-type allele was 97% for both men and women. The sensitivity of both mutations was 70% for men and 52% for women and the specificity was 62% for men and 64% for women. Our study shows that the HFE C282Y and H63D are determinants of iron parameters in the elderly and will be effective in detecting individuals at high risk of hemochromatosis. However, when screening based on these two mutations, some individuals with subclinical hemochromatosis will be missed.

A polymorphism in the IGF-I gene influences the age-related decline in circulating total IGF-I levels

OBJECTIVE

Recent studies have demonstrated an association between a 192 bp polymorphism of the IGF-I gene and total IGF-I serum levels, birth weight, body height and the risk of developing diabetes and cardiovascular diseases later on in life. This IGF-I gene polymorphism in the promoter region of the IGF-I gene may directly influence the expression of IGF-I. In the present study we evaluated the role of this polymorphism in the age-related decline in serum IGF-I levels.

SUBJECTS AND METHODS

All subjects were participants of the Rotterdam Study, a population-based cohort study of diseases in the elderly. We studied a total group of 346 subjects, who comprised two subgroups: a randomly selected population-based sample of 196 subjects, and a group of 150 subjects selected on IGF-I genotype. In the total group of 346 individuals the relationship between this 192 bp polymorphism and the age-related decline in circulating total IGF-I levels was studied.

RESULTS

Homozygous carriers of the 192 bp allele demonstrated significant decline in serum IGF-I with age (r=-0.29, P=0.002). This decline is similar to that seen in the general population. An age-related decline in serum total IGF-I was not observed in heterozygotes (r=-0.06, P=0.48) and non-carriers (r = -0.12, P=0.32). Interestingly, the relationship between age and serum IGF-binding protein-3 levels showed the same pattern.

CONCLUSION

We observed only in homozygous carriers of the 192 bp alleles of the IGF-I gene an age-related decline in circulating total IGF-I levels, but not in heterozygotes and non-carriers of the 192 bp allele. We hypothesize that this IGF-I gene polymorphism directly or indirectly influences GH-mediated regulation of IGF-I secretion.

Higher estrogen levels are not associated with larger hippocampi and better memory performance

BACKGROUND

Estrogens may prevent cognitive decline and Alzheimer disease. Animal study findings have shown beneficial effects of estrogen on the brain, particularly on the hippocampus, a structure related to memory performance and early Alzheimer disease.

OBJECTIVE

To investigate whether higher levels of endogenous estradiol in older women and men are associated with larger hippocampal volumes on magnetic resonance imaging and better memory performance.

DESIGN AND SETTING

Cross-sectional analysis within the Rotterdam Scan Study, a population-based study in the Netherlands of elderly subjects who do not have dementia.

PARTICIPANTS

Two hundred ten women and 202 men, aged 60 to 90 years, with plasma levels of total estradiol and, in part, 162 women and 149 men also with levels of bioavailable and free estradiol.

MAIN OUTCOME MEASURE

Hippocampal volumes on magnetic resonance imaging and memory performance (delayed recall).

RESULTS

Women with higher total estradiol levels had smaller hippocampal volumes and poorer memory performance -0.29 mL (95% confidence interval, -0.57 to -0.00) and -0.4 (95% confidence interval, -1.3 to 0.5) fewer words in delayed recall testing for the highest tertile compared with the lowest tertile. Similar inverse associations were found among bioavailable and free estradiol levels, hippocampal volumes, and memory. In men, no association was observed between estradiol levels and hippocampal volume, but a trend was found for higher levels of total estradiol to be associated with poorer memory performance.

CONCLUSION

Our data do not support the hypothesis that higher levels of endogenous estradiol in older women and men are associated with larger hippocampal volumes and better memory performance.

Determinants of incident vertebral fracture in men and women: results from the European Prospective Osteoporosis Study (EPOS)

The aim of this analysis was to determine the influence of lifestyle, anthropometric and reproductive factors on the subsequent risk of incident vertebral fracture in men and women aged 50-79 years. Subjects were recruited from population registers from 28 centers across Europe. At baseline, they completed an interviewer-administered questionnaire and had lateral thoraco-lumbar spine radiographs performed. Repeat spinal radiographs were performed a mean of 3.8 years later. Incident vertebral fractures were defined morphometrically and also qualitatively by an experienced radiologist. Poisson regression was used to determine the influence of the baseline risk factor variables on the occurrence of incident vertebral fracture. A total of 3173 men (mean age 63.1 years) and 3402 women (mean age 62.2 years) contributed data to the analysis. In total there were 193 incident morphometric and 224 qualitative fractures. In women, an age at menarche 16 years or older was associated with an increased risk of vertebral fracture (RR = 1.80; 95%CI 1.24, 2.63), whilst use of hormonal replacement was protective (RR = 0.58; 95%CI 0.34, 0.99). None of the lifestyle factors studied including smoking, alcohol intake, physical activity or milk consumption showed any consistent associations with incident vertebral fracture. In men and women, increasing body weight and body mass index were associated with a reduced risk of vertebral fracture though, apart from body mass index in men, the confidence intervals embraced unity. For most variables the strengths of the associations observed were similar using the qualitative and morphometric approaches to fracture definition. In conclusion our data suggest that modification of other lifestyle risk factors is unlikely to have a major impact on the population occurrence of vertebral fractures. The important biological mechanisms underlying vertebral fracture risk need to be explored using new investigational strategies.

Endogenous hormones and carotid atherosclerosis in elderly men

The aging process is characterized by a number of gradual changes in circulating hormone concentrations as well as a gradual increase in the degree of atherosclerosis. The authors studied whether serum hormone levels are related to atherosclerosis of the carotid artery in independently living, elderly men. In 1996, 403 men (aged 73-94 years) were randomly selected from the general population of Zoetermeer, the Netherlands. Carotid artery intima-media thickness was determined. Serum concentrations of testosterone; estrone; estradiol; dehydroepiandrosterone and dehydroepiandrosterone sulfate; insulin-like growth factor I (IGF-I) (total and free) and its binding proteins IGFBP-1, IGFBP-2, and IGFBP-3; and leptin were measured. After the authors adjusted for age, serum testosterone, estrone, and free IGF-I were inversely related to intima-media thickness. The strength of these relations was as powerful in subjects with as in those without prevalent cardiovascular disease. Serum estradiol; dehydroepiandrosterone sulfate; total IGF-I, IGFBP-1, IGFBP-2, and IGFBP-3; and leptin showed no association. These findings suggest that endogenous testosterone, estrone, and free IGF-I levels may play a protective role in the development of atherosclerosis in aging men.

Falls explain between-center differences in the incidence of limb fracture across Europe

There is important geographic variation in the occurrence of the major osteoporotic fractures across Europe. The aim of this study was to determine whether between-center variation in limb fracture rates across Europe could be explained by variation in the incidence of falls. Men and women, aged 50-79 years, were recruited from population-based registers in 30 European centers. Subjects were followed by postal questionnaire to ascertain the occurrence of incident fractures, and were also asked about the occurrence and number of recent falls. Self-reported fractures were confirmed, where possible, by review of the radiographs, medical record, or subject interview. The age- and gender-adjusted incidence of falls was calculated by center using Poisson regression. Poisson regression was also used to assess the extent to which between-center differences in the incidence of limb fractures could be explained by differences in the age- and gender-adjusted incidence of falls at those centers. In all, 6302 men (mean age 63.9 years) and 6761 women (mean age 63.1 years) completed at least one questionnaire concerning fractures and falls. During a median follow-up time of 3 years, 3647 falls were reported by men and 4783 by women. After adjusting for age and gender, there was evidence of significant between-center differences in the occurrence of falls. There was also between-center variation in the occurrence of upper limb, lower limb, and distal forearm fractures. Variation in the age- and gender-adjusted center-specific fall rates explained 24%, 14%, and 6% of the between-center variation in incidence of distal forearm and upper and lower limb fractures, respectively. Given the constraints inherent in such an analysis, in men and women aged 50-79 years, variation in fall rates could explain a significant proportion of the between-center variation in the incidence of limb fracture across Europe.

Osteoporosis in men and women: a story about bone mineral density thresholds and hip fracture risk

In postmenopausal women, the T score for bone mineral density (BMD) is a well-accepted diagnostic criterion for osteoporosis. It is also used to assess fracture risk. However, it is unclear whether in elderly men similar BMD thresholds should be used. Different hypotheses have been proposed for the relation of BMD with hip fracture risk in men. In this study, we tested those hypotheses using a mathematical model and we compared the calculated results with observed prospective data from the Rotterdam study. In the model, we combined the observed femoral neck BMD distribution for men and women with previously derived hip fracture risk functions based on age and BMD. For men, we tested different hypotheses for the relation of BMD with hip fracture risk. The relation of BMD with hip fracture risk is similar in men and women (scenario 1) or the relative risk (RR) per standard deviation (SD) decrease of BMD is either larger or smaller in men than in women (scenario 2a and 2b), or, at a similar absolute fracture risk, men have a higher BMD (scenario 3). In the prospective data, men with a hip fracture had an average BMD that was 0.070 g/cm2 higher than women with a hip fracture. The calculated results from the first scenario were consistent with those data and were also consistent with the observed hip fracture incidence and the observed female-to-male (F/M) risk ratio (1.7). When the RR for each SD decrease of BMD was assumed to be either larger or smaller in men than in women (second scenario), the calculated average BMD difference in men and women became respectively smaller or larger than observed. When men would have a higher fracture risk at similar BMD levels (third scenario), the calculated total number of hip fractures increased and even exceeded that in women, with an F/M risk ratio of 0.94 in our example. In women, a larger proportion of hip fractures occurs at a T score below -2.5 than in men using the same absolute BMD threshold, but using a male-specific T score largely solves this diagnostic problem. Taken together, the average hip fracture risk in men is much lower than in women but appeared to be similar at the same BMD. Therefore, we propose the use of the same absolute BMD thresholds for decisions about interventions.

The role of vitamin D receptor gene polymorphisms in bone biology

The role of vitamin D and its receptor (VDR) in skeletal metabolism is well known but the vitamin D endocrine system seems to play an important role in other metabolic pathways as well, such as those involved in osteoarthritis, the immune response and cancer. One approach to understand the vitamin D endocrine system is to study the influence of variations in the DNA sequence of important proteins of this system. For example, deleterious mutations in the VDR gene cause 1,25-dihydroxyvitamin D-resistant rickets, a rare monogenetic disease. More subtle sequence variations (polymorphisms) in the VDR gene occur much more frequently but their effects are poorly understood. Their influence on the vitamin D endocrine system is currently under scrutiny in relation to a number of so-called complex diseases and traits such as osteoporosis. The interpretation of polymorphic variations in the VDR gene is severely hindered by the fact that several of the polymorphisms used have unknown effects. However, current data indicate that dozens of additional polymorphic variations exist in the VDR gene that could each have different types of consequences. Therefore, efforts are focussed on finding novel sequence variations and to study their interaction in molecular- and cell-biological experiments as well as in genomic epidemiological studies. The ultimate goal of this approach is to identify the combinations of functional sequence variants that modulate the vitamin D endocrine system and confer risk of disease.

Collagen Ialpha1 polymorphism is associated with bone characteristics in Caucasian children and young adults

A large proportion of the variation in bone mass can be explained by genetic factors. We analyzed the G to T substitution in the Sp1 binding site in the first intron of the collagen type Ialpha1 (COLIA1) gene in relation to bone mass. The genotypes GG, GT, and TT were determined in 148 Caucasian children and young adults. We performed dual energy X-ray absorptiometry twice (mean follow-up time 4.4 years), and speed of sound (SOS) was assessed by tibial ultrasonometry at follow-up. Genotype distribution was 104 (70%) GG, 40 (27%) GT and 4 (3%) TT. Carriers of the T-allele had a 0.5 SDS (standard deviation score) decreased bone mineral content (BMC) of total body (P = 0.001), and a 0.4 SDS decreased bone mineral density (BMD) for both lumbar spine (P = 0.04) and total body (P = 0.05). The genotype effect on BMD and BMC decreased after adjustment for height or body mass index. When we calculated apparent BMD, these differences diminished to 0.1 SDS and were no longer significant. T-allele carriers had shorter stature (0.4 SDS; P = 0.04) and smaller bones (0.5 SDS lower width of the lumbar vertebral body; P = 0.01). The T-allele was also associated with lower SOS (P = 0.03), independent of BMD and BMC, and lower lean body mass. Similar associations were found at follow-up. The change in BMD and BMC SDS between the first and second measurement did not differ between the GG and GT&TT group. In conclusion, the COLIA1 polymorphism in children and young adults is associated with several bone characteristics. However, at least a part of the COLIA1 effect on bone mass may be related to differences in frame size.

Arterial stiffness in postmenopausal women: determinants of pulse wave velocity

OBJECTIVE To investigate the degree and potential cardiovascular determinants of arterial stiffness, assessed by aortic pulse wave velocity (PWV) measurements, and to relate arterial stiffness to absolute 10-12-year risks of stroke, coronary heart disease and death, as estimated by available risk functions, in postmenopausal women. METHOD We performed a cross-sectional study among 385 postmenopausal women, aged 50-74 years, sampled from the general population. Arterial stiffness was assessed non-invasively by measurement of aortic PWV using applanation tonometry. Information on health was obtained by medical history, registration of current medication, and physical examination. Height, weight, waist and hip circumferences, fasting glucose, total and high-density lipoprotein (HDL) cholesterol, triglycerides, resting blood pressure, and heart rate were measured. Three risk scores were used to estimate, for each individual, the absolute risk of stroke, coronary heart disease, and death within 10-12 years as a function of their cardiovascular risk factor profile. The relationship between PWV and these risk scores was subsequently determined. RESULTS Significant positive relationships with PWV were found for body mass index, fasting glucose, diabetes mellitus, and triglycerides in analyses adjusted for age, mean arterial blood pressure, and heart rate. Height and HDL cholesterol were inversely related to PWV. The risks of stroke, coronary heart disease, and death increased with increasing PWV in a linear graded manner. CONCLUSIONS This cross-sectional study among postmenopausal women provides evidence that most of the established cardiovascular risk factors are determinants of aortic PWV. Increased PWV marks an increased risk of stroke, coronary heart disease, and death within 10-12 years.

A polymorphism in the glucocorticoid receptor gene, which decreases sensitivity to glucocorticoids in vivo, is associated with low insulin and cholesterol levels

We investigated whether a polymorphism in codons 22 and 23 of the glucocorticoid (GC) receptor gene [GAGAGG(GluArg) --> GAAAAG(GluLys)] is associated with altered GC sensitivity, anthropometric parameters, cardiovascular risk factors, and sex steroid hormones. In a subgroup of 202 healthy elderly subjects of the Rotterdam Study, we identified 18 heterozygotes (8.9%) for the 22/23EK allele (ER22/23EK carriers). In the highest age group, the number of ER22/23EK carriers was higher (67-82 years, 12.9%) than in the youngest age group (53-67 years, 4.9%; P < 0.05). Two dexamethasone (DEX) suppression tests with 1 and 0.25 mg DEX were performed, and serum cortisol and insulin concentrations were compared between ER22/23EK carriers and noncarriers. After administration of 1 mg DEX, the ER22/23EK group had higher serum cortisol concentrations (54.8 +/- 18.3 vs. 26.4 +/- 1.4 nmol/l, P < 0.0001), as well as a smaller decrease in cortisol (467.0 +/- 31.7 vs. 484.5 +/- 10.3 nmol/l, P < 0.0001). ER22/23EK carriers had lower fasting insulin concentrations (P < 0.001), homeostasis model assessment- insulin resistance (IR) (index of IR, P < 0.05), and total (P < 0.02) and LDL cholesterol concentrations (P < 0.01). Our data suggest that carriers of the 22/23EK allele are relatively more resistant to the effects of GCs with respect to the sensitivity of the adrenal feedback mechanism than noncarriers, resulting in a better metabolic health profile.

Genetic polymorphisms and clinical practice: the example of osteoporosis

Over the past decades epidemiological research of so-called "complex" diseases, such as diabetes, osteoporosis, cancer, and cardiovascular disease, has identified a number of risk-factors for these common age-related disorders. Examples include obesity for diabetes, low bone mineral density for osteoporosis, and smoking for cancer and cardiovascular disease. Some of these risk factors are used in clinical practice, for example to identify subjects-at-risk and for monitoring treatment of patients with these diseases. More recently, a novel class of risk factors, genetic polymorphisms, has gained considerable interest in this respect. This is mostly due to the Human Genome Project which has identified every human gene and also uncovered a plethora of polymorphic variants of these genes which embody the genetic risk factors. Genetic risk factors are expected to find applications in early identification of subjects-at-risk, prediction of response-to-treatment, and development of novel therapeutic options. We will here discuss some developments in the field of the genetics of osteoporosis.

Efficacy of raloxifene on vertebral fracture risk reduction in postmenopausal women with osteoporosis: four-year results from a randomized clinical trial

The Multiple Outcomes of Raloxifene Evaluation trial studied 7705 postmenopausal women with osteoporosis randomized to placebo, or raloxifene 60 or 120 mg/d [JAMA 282(1999): 637]. This report assesses the efficacy of raloxifene on the long-term cumulative incidence new vertebral fractures through 4 yr. New vertebral fractures was assessed from radiographs taken at baseline, yr 2-4. The primary analysis was the cumulative incidence of new vertebral fractures through 4 yr. A posthoc analysis compared the vertebral fracture risk in yr 4 alone with that observed in the first 3 yr. The 4-yr cumulative relative risks (RR) for one or more new vertebral fractures were 0.64 [95% confidence interval (CI) 0.53, 0.76] with raloxifene 60 mg/d and 0.57 (95% CI 0.48, 0.69) with raloxifene 120 mg/d. In yr 4 alone, raloxifene 60 mg/d reduced the new vertebral fracture risk by 39% [RR 0.61 (95% CI 0.43, 0.88)], which was not found to be significantly different from the RR observed in the first 3 yr in both raloxifene groups, irrespective of prevalent fracture status. The nonvertebral fracture risk was not significantly reduced [RR 0.93 (95% CI 0.81, 1.06)]. The safety profile after 4 yr was similar to that observed after 3 yr. Raloxifene 60 and 120 mg/d through 4 yr decreased the cumulative risk of new vertebral fractures in postmenopausal women with osteoporosis. The decreased vertebral fracture risk in yr 4 alone was not different from that observed in the first 3 yr.

Low levels of endogenous androgens increase the risk of atherosclerosis in elderly men: the Rotterdam study

In both men and women, circulating androgen levels decline with advancing age. Until now, results of several small studies on the relationship between endogenous androgen levels and atherosclerosis have been inconsistent. In the population-based Rotterdam Study, we investigated the association of levels of dehydroepiandrosterone sulfate (DHEAS) and total and bioavailable testosterone with aortic atherosclerosis among 1,032 nonsmoking men and women aged 55 yr and over. Aortic atherosclerosis was assessed by radiographic detection of calcified deposits in the abdominal aorta, which have been shown to reflect intimal atherosclerosis. Relative to men with levels of total and bioavailable testosterone in the lowest tertile, men with levels of these hormones in the highest tertile had age-adjusted relative risks of 0.4 [95% confidence interval (CI), 0.2-0.9] and 0.2 (CI, 0.1-0.7), respectively, for the presence of severe aortic atherosclerosis. The corresponding relative risks for women were 3.7 (CI, 1.2-11.6) and 2.3 (CI, 0.7-7.8). Additional adjustment for cardiovascular disease risk factors did not materially affect the results in men, whereas in women the associations diluted. Men with levels of total and bioavailable testosterone in subsequent tertiles were also protected against progression of aortic atherosclerosis measured after 6.5 yr (SD +/- 0.5 yr) of follow-up (P for trend = 0.02). No clear association between levels of DHEAS and presence of severe aortic atherosclerosis was found, either in men or in women. In men, a protective effect of higher levels of DHEAS against progression of aortic atherosclerosis was suggested, but the corresponding test for trend did not reach statistical significance. In conclusion, we found an independent inverse association between levels of testosterone and aortic atherosclerosis in men. In women, positive associations between levels of testosterone and aortic atherosclerosis were largely due to adverse cardiovascular disease risk factors.

[CBO guideline 'Osteoporosis' (second revision]

Risk factors for osteoporotic fractures that can be used for case-finding according to the recent guidelines from the Dutch Institute for Health Care Improvement (CBO) include: a vertebral fracture, a fracture past the age of 50, a positive family history, low body weight, severe immobility and the use of corticosteroids. Measurement of bone mineral density (BMD) is only recommended for case-finding and not for population screening. Measurement of the BMD is advised in women > or = 50 years of age with a fracture, women with a vertebral fracture regardless of age, women > or = 60 years of age with three of the following risk factors, and women > or = 70 years of age with two of the following risk factors: positive family history, low body weight and severe immobility. Persons with less than 1000-1200 mg calcium in their daily food who are using corticosteroids, persons with osteoporotic fractures and persons who are being treated with drugs for osteoporosis are eligible for calcium supplementation. Vitamin D supplementation is recommended for persons who do not come outdoors. For the drug treatment of osteoporosis in the first years after menopause, oestrogens, tibolone and raloxifene may be used. It is recommended that postmenopausal women with one or more osteoporotic vertebral fractures or an increased risk and a T-score below -2.5 be treated with a bisphosphonate. Patients who are expected to be treated with > or = 15 mg prednisolone equivalent per day for more than 3 months and postmenopausal women and older men (> or = 70) who will be treated with > or = 7.5 mg prednisolone equivalent per day should be started on a bisphosphonate as soon as possible. Other patients who will be treated with > or = 7.5 mg prednisolone equivalent per day should take a bisphosphonate if their Z-score is below -1 or their T-score is below -2.5.

Incidence of limb fracture across Europe: results from the European Prospective Osteoporosis Study (EPOS)

The aim of this population-based prospective study was to determine the incidence of limb fracture by site and gender in different regions of Europe. Men and women aged 50-79 years were recruited from population registers in 31 European centers. Subjects were invited to attend for an interviewer-administered questionnaire and lateral spinal radiographs. Subjects were subsequently followed up using an annual postal questionnaire which included questions concerning the occurrence of new fractures. Self-reported fractures were confirmed where possible by radiograph, attending physician or subject interview. There were 6451 men and 6936 women followed for a median of 3.0 years. During this time there were 140 incident limb fractures in men and 391 in women. The age-adjusted incidence of any limb fracture was 7.3/1000 person-years [pyrs] in men and 19 per 1000 pyrs in women, equivalent to a 2.5 times excess in women. Among women, the incidence of hip, humerus and distal forearm fracture, though not 'other' limb fracture, increased with age, while in men only the incidence of hip and humerus fracture increased with age. Among women, there was evidence of significant variation in the occurrence of hip, distal forearm and humerus fractures across Europe, with incidence rates higher in Scandinavia than in other European regions, though for distal forearm fracture the incidence in east Europe was similar to that observed in Scandinavia. Among men, there was no evidence of significant geographic variation in the occurrence of these fractures. This is the first large population-based study to characterize the incidence of limb fracture in men and women over 50 years of age across Europe. There are substantial differences in the descriptive epidemiology of limb fracture by region and gender.

Bone mineral density and the risk of peripheral arterial disease: the Rotterdam Study

Low estrogen exposure throughout life is thought to result in low bone mineral density (BMD) and an increased incidence of cardiovascular disease. In the Rotterdam Study we cross-sectionally examined the relation between BMD and peripheral arterial disease (PAD), as assessed by an ankle-arm index (AAI) of <0.9 in either leg. Data on BMD and PAD were available for 5268 individuals (3053 women, 2215 men). From the BMD, Z-scores were calculated and subsequently divided into tertiles. Logistic regression analysis was used to compute odds ratios (OR) for PAD in tertiles of BMD, using the upper tertile as a reference. When adjusting for age, women with a low femoral neck BMD had a significantly increased risk of PAD (OR = 1.49, 95% CI 1.16-1.91). This could not be found for men (1.14, 0.84-1.53). The mid-tertile did not differ from the reference in either men or women. In women, additional adjustment for several potential confounders resulted in a somewhat lowered risk estimate (1.35, 1.02-1.79). In contrast, no association between lumbar spine BMD and PAD could be observed in either men or women. Our study shows an association between low femoral neck BMD and PAD in women only, an association unlikely to be causal. Estrogen deficiency may be the common denominator in osteoporosis and PAD, resulting in clustering of these two major diseases in postmenopausal women.

The incidence of vertebral fractures in men and women: the Rotterdam Study

Vertebral fractures are considered the most common fractures in osteoporosis. Nevertheless, little is known about the epidemiology of these fractures, especially in men. Therefore, the incidence of vertebral fractures was studied in 3469 men and women from the Rotterdam Study. Spinal radiographs were obtained at baseline and again after a mean follow-up of 6.3 years. The follow-up radiographs were scored for vertebral fractures using the McCloskey-Kanis assessment method. Whenever a vertebral fracture was detected, the radiograph was compared with the baseline radiograph. If this fracture was not already present at baseline, it was considered an incident fracture. The incidence increased strongly with age, ranging from 7.8/1,000 person years (PY) at ages 55-65 years to 19.6/1,000 PY at ages over 75 years for women, and 5.2-9.3/1,000 PY for men, respectively. Analyses repeated in strata of presence or absence of prevalent vertebral fractures showed that both in men and in women, the increase in incidence with age was almost exclusively observed in subjects with one or more prevalent fractures present at baseline. For both genders, the incidence of vertebral fractures doubled per SD decrease in lumbar spine or femoral neck bone mineral density (BMD). This study shows that overall, the incidence of vertebral fractures is higher in women-than in men. In both genders, the incidence increases with age. Furthermore, the presence of a prevalent vertebral fracture and a low BMD are strong independent predictors of incident vertebral fractures in men and women.

The collagen Ia1 SP1 polymorphism is associated with differences in ultrasound transmission velocity in the calcaneus in postmenopausal women

Bone mineral density (BMD) and fracture risk are under genetic control. An association of a G to T polymorphism in the Sp1 binding site of the collagen Ia1 (COLIa1) gene with the risk for fractures has been previously reported. This association is only partly explained by differences in BMD. Thus, we analyzed the relationship between the COLIa1 Sp1 polymorphism and ultrasound (US) transmission velocity (speed of sound; SOS) in bone. In a population-based sample of 740 women (aged 55-80 years) we determined COLIa1 genotype and US parameters in the calcaneus. SOS in the "GG" genotype group was 1522 +/- 31 m/sec, in the "GT" group, 1519 +/- 30 m/sec, and in the "TT" group 1508 +/- 30 m/sec (P = 0.01). While the difference between the GG and TT genotype groups corresponds to 0.5 SD or 1%, we observed an allele-dose-effect of 4.3 m/sec decrease in SOS per each copy of the "T" allele (P = 0.01). The differences remained significant after adjustment for BMD measured at the femoral neck. When we analysed 45 incident nonvertebral fractures in this group of women, we found the risk for fracture by COLIA1 Sp1 genotype to be partly explained by SOS differences as well as by BMD differences. Linear regression analysis showed a progressive negative slope of the regression line of SOS over age from "GG" over "GT" to "TT" genotype. These data indicate that the collagen Ia1 Sp1 polymorphism is associated with the modulus of elasticity of bone as determined in vivo by acoustical measurement. The relationship is independent of BMD and increases with age, contributing to an explanation of the increased fracture risk observed for this polymorphism.

A central dinucleotide within vitamin D response elements modulates DNA binding and transactivation by the vitamin D receptor in cellular response to natural and synthetic ligands

There is considerable divergence in the sequences of steroid receptor response elements, including the vitamin D response elements (VDREs). Two major VDRE-containing and thus 1,25-dihydroxyvitamin D(3) (1,25-(OH)(2)D(3))-regulated genes are the two non-collagenous, osteoblast-derived bone matrix proteins osteocalcin and osteopontin. We observed a stronger induction of osteopontin than osteocalcin mRNA expression by 1,25-(OH)(2)D(3). Subsequently, we have shown that vitamin D receptor/retinoid X receptor alpha (VDR/RXRalpha) heterodimers bind more tightly to the osteopontin VDRE than to the osteocalcin VDRE. Studies using point mutants revealed that the internal dinucleotide at positions 3 and 4 of the proximal steroid half-element are most important for modulating the strength of receptor binding. In addition, studies with VDRE-driven luciferase reporter gene constructs revealed that the central dinucleotide influences the transactivation potential of VDR/RXRalpha with the same order of magnitude as that observed in the DNA binding studies. The synthetic vitamin D analog KH1060 is a more potent stimulator of transcription and inducer of VDRE binding of VDR/RXR in the presence of nuclear factors isolated from ROS 17/2.8 osteoblast-like cells than the natural ligand 1,25-(OH)(2)D(3). Interestingly, however, KH1060 is comparable or even less potent than 1,25-(OH)(2)D(3) in stimulating VDRE binding of in vitro synthesized VDR/RXRalpha. Thus, the extent of 1,25-(OH)(2)D(3)- and KH1060-dependent binding of VDR/RXRalpha is specified by a central dinucleotide in the VDRE, and the ligand-induced effects on DNA binding are in part controlled by the cellular context of nuclear proteins.

Bone mineral density and mortality in elderly men and women: the Rotterdam Study

Recent studies have shown that a low bone mineral density (BMD) is associated with a higher risk of mortality. Most studies have investigated this relationship in women only and presented their risk estimates per standard deviation change in BMD. However, when using this approach, a BMD threshold might be missed when relative risks are presented in the traditional manner. Therefore, in this study our aim was to model the relation between BMD and all-cause mortality. In the Rotterdam Study, follow-up was complete for 5819 men and women aged > or =55 years for whom BMD data were available. During an average follow-up of 5.4 years, 399 men and 317 women died. We calculated BMD Z scores using measurements performed at the femoral neck. Cox proportional hazards regression was used to fit the model. An average BMD, reflected by a Z score = 0, was used as the reference. For women, no significant relationship between BMD and overall mortality was observed. For men, however, a cubic model best fitted the relationship under study, also after adjusting for age and body mass index (BMI). The risk of mortality increased when BMD was below average. Similar results were found when separate curves were made for diabetics and nondiabetics, smokers (ever or never), and tertiles of BMI. Excluding subjects who had suffered hip fractures, or adjusting for the number of drugs used and for lower limb disability, essentially did not change results. This suggests that low BMD is not mainly due to morbidity and impaired mobility in our cohort, which makes this a less likely explanation for the observed relation with mortality. The results of our study suggest that, in men, a nonlinear relationship between BMD and mortality exists, which is independent of comorbidity, whereas, in women, no significant relationship was observed.

Incidence of vertebral fracture in europe: results from the European Prospective Osteoporosis Study (EPOS)

Vertebral fracture is one of the major adverse clinical consequences of osteoporosis; however, there are few data concerning the incidence of vertebral fracture in population samples of men and women. The aim of this study was to determine the incidence of vertebral fracture in European men and women. A total of 14,011 men and women aged 50 years and over were recruited from population-based registers in 29 European centers and had an interviewer-administered questionnaire and lateral spinal radiographs performed. The response rate for participation in the study was approximately 50%. Repeat spinal radiographs were performed a mean of 3.8 years following the baseline film. All films were evaluated morphometrically. The definition of a morphometric fracture was a vertebra in which there was evidence of a 20% (+4 mm) or more reduction in anterior, middle, or posterior vertebral height between films--plus the additional requirement that a vertebra satisfy criteria for a prevalent deformity (using the McCloskey-Kanis method) in the follow-up film. There were 3174 men, mean age 63.1 years, and 3,614 women, mean age 62.2 years, with paired duplicate spinal radiographs (48% of those originally recruited to the baseline survey). The age standardized incidence of morphometric fracture was 10.7/1,000 person years (pyr) in women and 5.7/1,000 pyr in men. The age-standardized incidence of vertebral fracture as assessed qualitatively by the radiologist was broadly similar-12.1/1,000 pyr and 6.8/1,000 pyr, respectively. The incidence increased markedly with age in both men and women. There was some evidence of geographic variation in fracture occurrence; rates were higher in Sweden than elsewhere in Europe. This is the first large population-based study to ascertain the incidence of vertebral fracture in men and women over 50 years of age across Europe. The data confirm the frequent occurrence of the disorder in men as well as in women and the rise in incidence with age.

Association between genetic variation in the gene for insulin-like growth factor-I and low birthweight

Low birthweight is associated with later risk of type 2 diabetes and related disorders. We aimed to show that a polymorphism in the gene for insulin-like growth factor-I, which has proved to raise risk of type 2 diabetes and myocardial infarction, is associated with low birthweight. We recorded birthweight and obtained DNA for 463 adults. Individuals who did not have the wild-type allele of the polymorphism had a 215 g lower birthweight than those homozygous for this allele (95% CI -411 to -10). Our data lend support to the hypothesis that genetic variation affecting fetal growth could account for the association between low birthweight and susceptibility to diabetes and cardiovascular disease in later life.

Improving risk assessment: hip geometry, bone mineral distribution and bone strength in hip fracture cases and controls. The EPOS study. European Prospective Osteoporosis Study

Hip geometry and bone mineral density (BMD) have previously been shown to relate independently to hip fracture risk. Our objective was to determine by how much hip geometric data improved the identification of hip fracture. Lunar pencil beam scans of the proximal femur were obtained. Geometric and densitometric values from 800 female controls aged 60 years or more (from population samples which were participants in the European Prospective Osteoporosis Study, EPOS) were compared with data from 68 female hip fracture patients aged over 60 years who were scanned within 4 weeks of a contralateral hip fracture. We used Lunar DPX 'beta' versions of hip strength analysis (HSA) and hip axis length (HAL) applied to DPX(L) data. Compressive stress (Cstress), calculated by the HSA software to occur as a result of a typical fall on the greater trochanter, HAL, body mass index (BMI: weight/(height)2) and age were considered alongside femoral neck BMD (FN-BMD, g/cm2) as potential predictors of fracture. Logistic regression was used to generate predictors of fracture initially from FN-BMD. Next age, Cstress (as the most discriminating HSA-derived parameter), HAL and BMI were added to the model as potentially independent predictors. It was not necessary to include both HAL and Cstress in the logistic models, so the entire data set was examined without excluding the subjects missing HAL measurements. Cstress combined with age and BMI provided significantly better prediction of fracture than FN-BMD used alone as is current practice, judged by comparing areas under receiver operating characteristic (ROC) curves (p<0.001, deLong's test). At a specificity of 80%, sensitivity in identification was improved from 66% to 81%. Identifying women at high risk of hip fracture is thus likely to be substantially enhanced by combining bone density with age, simple anthropometry and data on the structural geometry of the hip. HSA might prove to be a valuable enhancement of DXA densitometry in clinical practice and its use could justify a more proactive approach to identifying women at high risk of hip fracture in the community.