| 1. |
- Glynn, A. Wicklund, et al.
(författare)
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Organochlorines and bone mineral density in Swedish men from the general population
- 2000
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Ingår i: Osteoporosis International. - : Springer Science and Business Media LLC. - 0937-941X .- 1433-2965. ; 11:12, s. 1036-1042
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Tidskriftsartikel (refereegranskat)abstract
- Persistent organochlorines (POCs), such as polychlorinated biphenyls (PCBs) and DDT, are present at relatively high concentrations in food and show estrogenic, anti-estrogenic or anti-androgenic activity in biological test systems. Because bone mineral density (BMD) in men is influenced by sex hormones, we looked for associations between BMD and serum concentrations of POCs in 115 men (mean age 63 years, range 40-75 years) from the general Swedish population. Ten PCB congeners, five DDT isomers, hexachlorobenzene, three hexachlorocyclohexane isomers, trans-nonachlor and oxychlordane were analyzed by gas chromatography. Quantitative bone measurements were performed by dual-energy X-ray absorptiometry at three sites: whole body, the L2-L4 region of the lumbar spine, and the neck region of the proximal femur, as well as by quantitative ultrasound on the left os calcis (broadband ultrasound attenuation (BUA) and speed of sound (SOS)). After adjustment for confounding factors in linear regression analyses we found no strong association between serum concentrations of single POCs and the five BMD and ultrasound variables. When POCs were grouped according to hormonal activity (estrogenic, anti-estrogenic, anti-androgenic) and the study subjects were divided into organochlorine concentration quartiles, a weak association was indicated between increased serum concentrations of p,p'-DDE (antiandrogenic) and decreased BMD, BUA and SOS. This may suggest that p,p'-DDE could cause negative effects on bone density, but the findings might also be due to chance since multiple comparisons were made in the statistical analysis. Overall our results do not suggest that the studied POCs caused major effects on bone density in our study group.
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| 2. |
- Melhus, Håkan, et al.
(författare)
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Excessive dietary intake of vitamin A is associated with reduced bone mineral density and increased risk for hip fracture
- 1998
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Ingår i: Annals of Internal Medicine. - : American College of Physicians. - 0003-4819 .- 1539-3704. ; 129:10, s. 770-8
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The highest incidence of osteoporotic fractures is found in northern Europe, where dietary intake of vitamin A (retinol) is unusually high. In animals, the most common adverse effect of toxic doses of retinol is spontaneous fracture. OBJECTIVE: To investigate whether excessive dietary intake of vitamin A is associated with decreased bone mineral density and increased risk for hip fracture. DESIGN: A cross-sectional study and a nested case-control study. SETTING: Two counties in central Sweden. PARTICIPANTS: For the cross-sectional study, 175 women 28 to 74 years of age were randomly selected. For the nested case-control study, 247 women who had a first hip fracture within 2 to 64 months after enrollment and 873 age-matched controls were selected from a mammography study cohort of 66,651 women 40 to 76 years of age. MEASUREMENTS: Retinol intake was estimated from dietary records and a food-frequency questionnaire. Bone mineral density was measured with dual-energy x-ray absorptiometry. Hip fracture was identified by using hospital discharge records and was confirmed by record review. RESULTS: In multivariate analysis, retinol intake was negatively associated with bone mineral density. For every 1-mg increase in daily intake of retinol, risk for hip fracture increased by 68% (95% CI, 18% to 140%; P for trend, 0.006). For intake greater than 1.5 mg/d compared with intake less than 0.5 mg/d, bone mineral density was reduced by 10% at the femoral neck (P = 0.05), 14% at the lumbar spine (P = 0.001), and 6% for the total body (P = 0.009) and risk for hip fracture was doubled (odds ratio, 2.1 [CI, 1.1 to 4.0]). CONCLUSION: High dietary intake of retinol seems to be associated with osteoporosis.
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| 3. |
- Michaëlsson, Karl, et al.
(författare)
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A high dietary calcium intake is needed for a positive effect on bone density in Swedish postmenopausal women
- 1997
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Ingår i: Osteoporosis International. - 0937-941X .- 1433-2965. ; 7:2, s. 155-161
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Tidskriftsartikel (refereegranskat)abstract
- The importance of dietary calcium for bone health is unclear, partly since most investigations have dealt only with a fairly narrow range of calcium intake. In the present population-based observational study with longitudinal dietary assessment, we investigated women with a mean age of 60 years and with a consistently high (range 1417-2417, mean 1645 mg, n = 40), intermediate (800-1200, mean 1006 mg, n = 35) or low (400-550, mean 465 mg, n = 40) estimated daily consumption of calcium. Measurements of bone mineral density (BMD) of the lumbar spine, femoral neck and total body were performed by dual-energy X-ray absorptiometry, as well as ultrasound of the heel. In a multivariate analysis, with adjustment for energy intake the risk factors for osteoporosis (age, body mass index, physical activity, menopausal age, use of estrogens, smoking and former athletic activity), the group with the highest calcium intake had higher values for BMD than the others at all measured sites. The average mean difference compared with the low and the intermediate calcium group was 11% for the femoral neck, 8-11% for the lumbar spine and 5-6% for total body BMDs. In univariate analyses and multivariate models which did not include energy intake, the differences between the groups were less pronounced. The women in the intermediate calcium group had approximately the same mean BMD values as those in the low calcium group. These findings support the view that only a high calcium intake (3% highest percentiles in the studied population) protects against osteoporosis in Swedish postmenopausal women.
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| 4. |
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| 5. |
- Michaëlsson, Karl, et al.
(författare)
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Diet and Hip Fracture Risk - A Case-control Study : Study Group of the Multiple Risk Survey on Swedish Women for Eating Assessment
- 1995
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Ingår i: International Journal of Epidemiology. - 0300-5771 .- 1464-3685. ; 24:4, s. 771-782
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- BACKGROUND. The role of diet as a risk factor for osteoporotic fractures is unclear. Earlier studies have yielded conflicting results. METHODS. In two counties in central Sweden we investigated the association between dietary intake and the risk of proximal femoral fractures in a case-control study nested in a cohort. Women born in 1914-1948 were asked to fill out a food frequency questionnaire when invited to attend for mammographic screening between the years 1987 and 1990. More than 65,000 women completed the questionnaire. Those who had participated in the enquiry and subsequently sustained a first hip fracture were defined as cases. For every case, four individually matched controls, by age and county of residence, were selected from the cohort. A second questionnaire concerning confounding factors was mailed to controls and cases. In all, 247 cases and 893 controls could finally be included. Monthly intake of foods and daily intake of nutrients were calculated. RESULTS. When highest quartile of intake was compared to lowest, intakes of iron (adjusted odds ratio [OR] of 3.3, 95% confidence interval [CI]: 1.6-6.9), magnesium (adjusted OR = 2.7, 95% CI: 1.3-6.0) and vitamin C (adjusted OR = 1.9, 95% CI: 1.2-3.1) were found to be independent risk factors for hip fracture. High calcium intake did not protect against hip fracture. Smoking, low physical activity in leisure time, low body mass index, earlier fracture of the distal forearm and diabetes were all risk factors while postmenopausal hormone replacement therapy protected against hip fracture. DISCUSSION. This large study indicates new dietary risk factors for hip fracture. The association between high dietary intake of iron, magnesium and vitamin C and risk of hip fracture has not been reported previously. Further clinical and experimental studies are needed to confirm these findings and to investigate their mechanism of action.
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| 6. |
- Michaëlsson, Karl, 1959-, et al.
(författare)
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Diet, bone mass, and osteocalcin : A cross-sectional study
- 1995
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Ingår i: Calcified Tissue International. - 0171-967X .- 1432-0827. ; 57:2, s. 86-93
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Tidskriftsartikel (refereegranskat)abstract
- To determine the relationships among nutrients intake, bone mass, and bone turnover in women we have investigated these issues in a population-based, cross-sectional, observational study in one county in central Sweden. A total of 175 women aged 28-74 at entry to the study were included. Dietary assessment was made by both a semiquantitative food frequency questionnaire and by four 1-week dietary records. Dual energy X-ray absorptiometry was performed at five sites: total body, L2-L4 region of the lumbar spine, and three regions of the proximal femur. Serum concentrations of osteocalcin (an osteoblast-specific protein reflecting bone turnover) were measured by a radioimmunoassay. Linear regression models, with adjustment for possible confounding factors were used for statistical analyses. A weak positive association was found between dietary calcium intake as calculated from the semiquantitative food frequency questionnaire and total body bone mineral density (BMD) among premenopausal women. No association emerged between dietary calcium intake and site-specific bone mass, i.e., lumbar spine and femoral neck, nor was an association found between dietary calcium intake and serum osteocalcin. BMD at some of the measured sites was positively associated with protein and carbohydrates and negatively associated with dietary fat. In no previous studies of diet and bone mass have dietary habits been ascertained so carefully and the results adjusted for possible confounding factors. Neither of the two methods of dietary assessment used in this study revealed any effect of calcium intake on BMD at fracture-relevant sites among these healthy, mostly middle-aged women. A weak positive association was found between calcium intake estimates based on the food frequency questionnaire and total body BMD. In this study population the preventive effect of high dietary calcium on osteoporosis is probably very weak. The independent significance of protein, carbohydrates, and fat is uncertain.
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| 7. |
- Michaëlsson, Karl, 1959-, et al.
(författare)
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Effect of prefracture versus postfracture dietary assessment on hip fracture risk estimates
- 1996
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Ingår i: International Journal of Epidemiology. - : Oxford University Press (OUP). - 0300-5771 .- 1464-3685. ; 25:2, s. 403-10
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND. Dietary factors are presumed to have influence on bone mass and hence fracture susceptibility. Most information in this respect is based on retrospective assessment of previous dietary habits. In a population-based case-control study nested within a cohort, we collected dietary information both before and after a first hip fracture. Thus it was possible to study reported changes in dietary habits, intentional as well as unintentional, among hip fracture patients after a first hip fracture and to compare postfracture with prefracture dietary information. METHODS. More than 65 000 women born 1914-1948 in two counties in central Sweden completed a food frequency questionnaire regarding their usual current dietary habits, before attending a mammographic screening between the years 1987 and 1990. Subsequently 123 of them sustained a first hip fracture and were defined as cases in the present study. For every case, one control, individually matched by age and county of residence, was selected from the cohort. A second identical food frequency questionnaire was mailed to both cases and controls on average 2 years after the hip fracture event. In total 98 case/control pairs could be included in the analysis. The association between diet and hip fracture was evaluated and the results from the two dietary assessments were contrasted. Women who themselves claimed that they had not changed their diet in recent years were analysed separately. RESULTS. The hip fracture cases, compared with the controls, had reduced their reported dietary intake of dairy products after the fracture. Apparently this was not intentional since this effect was more pronounced among those cases who claimed that their diet was unchanged. The changes were most apparent among the younger cases with a more recent hip fracture and with a body mass index above the median. Half of the cases, more than twice the frequency in controls, who were initially classified as having high intake of dairy products were classified as having low intake (<800 mg calcium/day) after the hip fracture. This also lowered, in fact reversed, the relative risk estimates of hip fracture both for intake of dairy products and calcium. Crude odds ratios of highest quartile of intake versus lowest, changed from 3.0 to 0.6 for dairy products and from 2.6 to 0.9 for calcium. No other foods or nutrients displayed such notable differences between the two surveys. CONCLUSION. We conclude that the use of current and retrospective dietary information after a hip fracture can lead to a differential misclassification in dietary studies and to biased estimates of hip fracture risk as compared with prospectively collected dietary information.
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| 8. |
- Michaëlsson, Karl, 1959-, et al.
(författare)
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Screening for osteopenia and osteoporosis : selection by body composition
- 1996
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Ingår i: Osteoporosis International. - 0937-941X .- 1433-2965. ; 6:2, s. 120-126
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Tidskriftsartikel (refereegranskat)abstract
- There is a great need for simple means of identifying persons at low risk of developing osteoporosis, in order to exclude them from screening with bone mineral measurements, since this procedure is too expensive and time-consuming for general use in the unselected population. We have determined the relationships between body measure (weight, height, body mass index, lean tissue mass, fat mass, waist-to-hip ratio) and bone mineral density (BMD) in 175 women of ages 28-74 years in a cross-sectional study in a county in central Sweden. Dual-energy X-ray absorptiometry was performed at three sites: total body, L2-4 region of lumbar spine, and neck region of the proximal femur. Using multiple linear regression models, the relationship between the dependent variable, BMD, and each of the body measures was determined, with adjustment for confounding factors. Weight alone, in a multivariate model, explained 28%, 21% and 15% of the variance in BMD of total body, at the lumbar spine and at the femoral neck according to these models. The WHO definition of osteopenia was used to dichotomize BMD, which made it possible, in multivariate logistic regression models, to estimate the risk of osteopenia with different body measures categorized into tertiles. Weight of over 71 kg was associated with a very low risk of being osteopenic compared with women weighing less than 64 kg, with odds ratios (OR) of 0.01 (95% confidence interval (CI) 0.00-0.09), 0.06 (CI 0.02-0.22) and 0.13 (CI 0.04-0.42) for osteopenia of total body, lumbar spine and femoral neck, respectively. Furthermore a sensitivity/specificity analysis revealed that, in this population, a woman weighing over 70 kg is not likely to have osteoporosis. Test specifics of a weight under 70 kg for osteoporosis (BMD less than 2.5 SD compared with normal young women) of femoral neck among the postmenopausal women showed a sensitivity of 0.94, a specificity of 0.36, positive predictive value (PPV) of 0.21, and negative predictive value (NPV) of 0.97. Thus, exclusion of the 33% of women with the highest weight meant only that 3% of osteoporotic cases were missed. The corresponding figures for lumbar spine were sensitivity 0.89, specificity 0.38, PPV 0.33, and NPV 0.91. All women who were defined as being osteoporotic of total body weighed under 62 kg. When the intention was to identify those with osteopenia of total body among the postmenopausal women we attained a sensitivity of 0.92 and a NPV of 0.91 for a weight under 70 kg, whereas we found that weight could not be used as an exclusion criterion for osteopenia of femoral neck and lumbar spine. Our data thus indicate that weight could be used to exclude women from a screening program for postmenopausal osteoporosis.
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| 9. |
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| 10. |
- Michaëlsson, Karl, et al.
(författare)
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The positive effect of dietary vitamin D intake on bone mineral density in men is modulated by the polyadenosine repeat polymorphism of the vitamin D receptor
- 2006
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Ingår i: Bone. - : Elsevier BV. - 8756-3282 .- 1873-2763. ; 39:6, s. 1343-1351
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Few studies have considered the dietary influence of vitamin D intake on bone mineral density (BMD). Numerous studies have examined the association between VDR polymorphism and BMD, but no previous study has examined the joint influence of dietary vitamin D intake and VDR polymorphism on BMD. METHODS: We therefore conducted a study in 230 men aged 41-76 years of age. BMD was measured with DXA. A second bone scan was performed on average 2.7 years after the first investigation. Dietary habits were assessed by 14 dietary 24-h recall interviews. The polyadenosine (A) VDR genotypes were determined. RESULTS: Dietary vitamin D intake was associated with BMD at all sites, also after multivariate adjustment. Those in the highest quintile of intake had 9% higher femoral neck BMD (p = 0.004), 6% higher BMD at the lumbar spine (p = 0.06) and 5% higher total body BMD (p = 0.003) compared to men in the lowest quintile of dietary vitamin D intake. However, the positive association between vitamin D intake and BMD was especially apparent among those with the L/L polyadenosine (A) VDR genotype explaining between 10 and 15% of the variability in BMD depending on site (p < 0.004). There was furthermore a trend, in the lumbar spine, of less reduction in BMD with increasing vitamin D intake (p = 0.07) but not at the other sites. Calcium intake conferred no association with BMD. CONCLUSIONS: Our results indicate that the extent of positive association between dietary vitamin D intake and BMD in men is dependent on VDR polymorphism, a novel conceivable important gene-environmental interaction.
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