Ellen M. Apalset

Vitamin D inadequacy is associated with low-energy distal radius fractures: A case–control study

INTRODUCTION Vitamin D inadequacy is associated with hip fractures, but the relationship has not been explored for distal radius fractures. AIMS To compare serum 25-hydroxyvitamin D (s-25(OH)D) status in low-energy distal radius fracture patients and a group of matched controls, and examine whether observed differences in s-25(OH)D between patients and controls would remain after adjusting for bone mineral density (BMD), body mass index (BMI), and smoking history. METHODS A total of 575 female and 72 male low-energy distal radius fracture patients (50-90 years) and 534 female and 52 male matched controls were included. The primary measure was levels of vitamin D. Secondary measures were BMD assessed by dual energy X-ray absorptiometry, BMI and smoking history. RESULTS Mean s-25(OH)D was 66.5nmol/L in female patients and 78.7nmol/L in controls (p<0.001). The corresponding figures in men were 64.5 and 77.0nmol/L (p=0.017). In adjusted conditional logistic regression analyzes, s-25(OH)D <50nmol/L (OR=2.32, 95% CI: 1.47-3.64, p<0.001), and 50-75 (OR=1.70, 95% CI: 1.17-2.47, p=0.005) were associated with distal radius fractures in women. s-25(OH)D <50nmol/L (OR=6.27, 95% CI: 1.17-33.66, p=0.032) was associated with distal radius fractures in men. CONCLUSIONS Vitamin D inadequacy is associated with low-energy distal radius fractures in both women and men. Differences in vitamin D levels are independent of BMD, BMI or smoking history.

Intake of vitamin K1 and K2 and risk of hip fractures: The Hordaland Health Study

BACKGROUND Evidence of the effect of vitamin K on bone health is conflicting. The aim was to investigate the association between intake of vitamins K1 and K2 and subsequent risk of hip fracture in a general population sample, as well as potential effect modification by apolipoprotein E gene (APOE) status by presence of the E4 allele. METHODS 1238 men and 1569 women 71-75 years of age were included in the community-based Hordaland Health Study 1997-1999 in Western Norway. Information on hip fracture was obtained from hospitalizations in the region from enrolment until 31 December 2009. Information on intake of vitamins K1 and K2 collected at baseline was used as potential predictors of hip fracture in Cox proportional hazards regression analyses. RESULTS Participants in the lowest compared to the highest quartile of vitamin K1 intake had increased risk of suffering a hip fracture (hazard ratio (HR)=1.57 [95% CI 1.09, 2.26]). Vitamin K2 intake was not associated with hip fracture. Presence of APOE4-allele did not increase the risk of hip fracture, nor was there any effect modification with vitamin K1 in relation to risk of hip fracture. CONCLUSIONS A low intake of vitamin K1, but not K2, was associated with an increased risk of hip fractures.

Celiac disease and risk of fracture in adults--a review.

Patients with celiac disease (CD) have low bone mineral density. Evidence of increased fracture risk in these patients is conflicting, and the indication for bone mineral density screening of all adult CD patients is debated. Our aim was to review current published data on fractures in CD. Cross-sectional cohort studies and one case study were identified by searching Medline and Embase. Although the identified studies are heterogeneous and difficult to compare, the overall findings indicate a positive association between CD and risk of fracture. Adult patients with CD should be considered for bone densitometry in order to estimate fracture risk.

Interferon (IFN)‐γ‐mediated inflammation and the kynurenine pathway in relation to bone mineral density: the Hordaland Health Study

The risk of osteoporosis increases in inflammatory disorders. In cell‐mediated immune activation, interferon (IFN)‐γ stimulates macrophage release of neopterin and increases the activity of indoleamine 2,3‐dioxygenase (IDO), thereby stimulating tryptophan degradation along the kynurenine pathway. Plasma levels of neopterin and the kynurenine/tryptophan ratio (KTR) are thus markers of IFN‐γ‐mediated inflammation. Several kynurenine pathway metabolites (kynurenines) possess immunomodulatory properties. The aim of this study was to investigate associations between markers of IFN‐γ‐mediated inflammation and kynurenines with bone mineral density (BMD). The community‐based Hordaland Health Study (HUSK), with middle‐aged (46–49 years) and older (71–74 years) participants, was conducted from 1998 to 2000 (n = 5312). Hip BMD in relation to neopterin, KTR and kynurenines were investigated, using linear and logistic regression analyses. In the oldest group, neopterin (P ≤ 0·019) and KTR (P ≤ 0·001) were associated inversely with BMD after multiple adjustment. Comparing the highest to the lowest quartiles, the odds ratios of low BMD (being in the lowest quintile of BMD) in the oldest cohort were for neopterin 2·01 among men and 2·34 among women (P ≤ 0·007) and for KTR 1·80 for men and 2·04 for women (P ≤ 0·022). Xanthurenic acid was associated positively with BMD in all sex and age groups while 3‐hydroxyanthranilic acid was associated positively with BMD among women only (P ≤ 0·010). In conclusion, we found an inverse association between BMD and markers of IFN‐γ‐mediated inflammation in the oldest participants. BMD was also associated with two kynurenines in both age groups. These results may support a role of cell‐mediated inflammation in bone metabolism.

1,25-Dihydroxyvitamin D and the Vitamin D Receptor Gene Polymorphism Apa1 Influence Bone Mineral Density in Primary Hyperparathyroidism

OBJECTIVE Parathyroid hormone (PTH) and vitamin D are the most important hormones regulating calcium metabolism. In primary hyperparathyroidism (PHPT) excessive amounts of PTH are produced. Bone turnover is enhanced, leading to reduced bone mineral density and elevated levels of serum calcium. The aim of this study was to investigate relations between serum levels of 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)(2)D) and bone mineral density, as well as known genetic polymorphisms in the vitamin D receptor and enzymes metabolising vitamin D in patients with PHPT. DESIGN/SUBJECTS We conducted a cross-sectional study of 52 patients with PHPT. RESULTS Mean level of 25(OH)D was 58.2 nmol/L and median 1,25(OH)(2)D level was 157 pmol/L. Among our patients with PHPT 36.5% had 25(OH)D levels below 50 nmol/L. Serum 1,25(OH)(2)D was inversely correlated to bone mineral density in distal radius (p = 0.002), but not to bone mineral density at lumbar spine or femoral neck. The vitamin D receptor polymorphism Apa1 (rs7975232) was associated with bone mineral density in the lumbar spine. CONCLUSIONS The results suggest that PHPT patients with high blood concentrations of 1,25(OH)(2)D may have the most deleterious skeletal effects. Randomized, prospective studies are necessary to elucidate whether vitamin D supplementation additionally increases serum 1,25(OH)(2)D and possibly enhances the adverse effects on the skeleton in patients with PHPT.

Smoking and body fat mass in relation to bone mineral density and hip fracture: The Hordaland Health Study

Lower bone mineral density (BMD) in smokers may be attributable to lower body weight or fat mass, rather than to a direct effect of smoking. We analyzed the effects of smoking exposure, assessed by plasma cotinine, and body fat on BMD and the risk of subsequent hip fracture. In the community-based Hordaland Health Study (HUSK), 3003 participants 46–49 years and 2091 subjects 71–74 years were included. Cotinine was measured in plasma and information on health behaviors was obtained from self-administered questionnaires. BMD and total body soft tissue composition were measured by dual X-ray absorptiometry. Information on hip fracture was obtained from computerized records containing discharge diagnoses for hospitalizations between baseline examinations 1997–2000 through December 31st, 2009. In the whole cohort, moderate and heavy smokers had stronger positive associations between fat mass and BMD compared to never smokers (differences in regression coefficient (95% CI) per % change in fat mass = 1.38 (0.24, 2.52) and 1.29 (0.17, 2.4), respectively). In moderate and heavy smokers there was a nonlinear association between BMD and fat mass with a stronger positive association at low compared to high levels of fat mass (Davies segmented test, p<0.001). In elderly women and men, heavy smokers had an increased risk of hip fracture compared to never smokers (hazard ratio = 3.31, 95% CI: 2.05, 5.35; p<0.001). In heavy smokers there was a tendency of a lower risk of hip fracture with higher percentage of fat mass. The deleterious effect of smoking on bone health is stronger in lean smokers than in smokers with high fat mass.

Procollagen type 1 amino-terminal propeptide (P1NP) and risk of hip fractures in elderly Norwegian men and women. A NOREPOS study

The current study aimed to assess a possible association between the bone turnover marker procollagen type 1 amino-terminal propeptide (P1NP) and future hip fractures in elderly Norwegian men and women and to elucidate the relation between P1NP, bone mineral density and 25-hydroxyvitamin D (25(OH)D). Men and women aged 71 to 77 from two population based health studies in Norway (1999-2001) were followed for a median period of 7.3 years with respect to hip fractures. The study was designed as a case-cohort study. P1NP and 25(OH)D were analysed in frozen serum samples obtained at baseline in hip fracture patients (n=340) and in randomly selected sex stratified sub-cohorts. Bone mineral density was measured by dual-energy X-ray absorptiometry (DXA) in a subset of participants. Cox proportional hazards regression with inverse probability weighting and robust variance was performed. No significant correlation between 25(OH)D and P1NP was found. A negative correlation between P1NP and BMD was observed in women (Rho=-0.36, p=0.001). A similar trend was observed in men. No association between quartiles of P1NP and rate of subsequent hip fractures was found. Spline analyses suggested a higher rate of hip fracture at P1NP levels above 60 μg/L in both men and women. A higher hip fracture rate, which was independent of BMD, was also indicated in women with very low levels of P1NP.

Positive predictive values of ICD-10 codes to identify incident acute pancreatitis and incident primary malignancy in the Scandinavian national patient registries among women with postmenopausal osteoporosis

Background Validation of definitions used to identify conditions of interest is imperative to epidemiologic studies based on routinely collected data. The objective of the study was thus to estimate positive predictive values (PPVs) of International Classification of Diseases, 10th Revision (ICD-10) codes to identify cases of incident acute pancreatitis leading to hospitalization and incident primary malignancy in the Scandinavian (Denmark, Norway, and Sweden) national patient registries in women with postmenopausal osteoporosis (PMO). Methods This validation study included postmenopausal (defined as 55 years or older) women with osteoporosis, identified between 2005–2014. Potential cases were sampled based on ICD-10 codes from the three national patient registries. Cases were adjudicated by physicians, using medical record review as gold standard. PPVs with corresponding 95% CIs were computed. Results Medical records of 286 of 325 (retrieval rate 88%) women with PMO were available for adjudication. Acute pancreatitis leading to hospitalization had a PPV of 87.6% (95% CI: 80.8%–90.2%). Incident primary malignancy had a PPV of 88.1% (95% CI: 81.3%–92.7%). The PPVs did not vary substantially across the three countries. Conclusion ICD-10 codes to identify acute pancreatitis leading to hospitalization, and incident primary malignancy in the Scandinavian national patient registries had high PPVs among women with PMO. This allows identification of cases of acute pancreatitis and incident primary malignancy with reasonable validity and to use these as outcomes in comparative analyses.

Positive IgA against transglutaminase 2 in patients with distal radius and ankle fractures compared to community-based controls

Abstract Background: Patients with celiac disease (CD), including adults with subclinical disease, have low bone mineral density (BMD), deteriorated bone microarchitecture and meta-analysis show an increased risk of fracture. Immunoglobulin A (IgA) against transglutaminase 2 (IgA TG2) is a highly reliable marker to detect CD. Main objective: To explore the prevalence of positive IgA TG2 and CD in patients with distal radius and ankle fracture compared to community-based controls. Methods: Four hundred patients aged 40 years or above with distal fractures were included in a case–control study. About 197 controls were identified from the National Population Registry, those included had never suffered a fracture. BMD was measured, and comorbidities, medications, physical activity, smoking habits, body mass index (BMI) and nutritional factors were registered. Blood analysis to detect common causes of secondary osteoporosis was performed. Results: About 2.5% of the fracture patients had positive IgA TG2, compared to 1% in the control group. The odds ratio, adjusted for sex and age, of having positive IgA TG2 was 2.50 (95% CI 0.54–11.56). Conclusions: There were no significantly increased odds of CD in adult patients with fractures compared to controls; however, results imply that positive IgA TG2 is more prevalent in fracture patients than in controls. This study indicates that universal screening for CD in fracture patients is not warranted, but supports current clinical practice in Norway to suspect and investigate for CD in patients with fracture, osteoporosis and other risk factors for CD.

Positive predictive values of International Classification of Diseases, 10th revision codes for dermatologic events and hypersensitivity leading to hospitalization or emergency room visit among women with postmenopausal osteoporosis in the Danish and Swedish national patient registries

Background Clinical epidemiology research studies, including pharmacoepidemiology and pharmacovigilance studies, use routinely collected health data, such as diagnoses recorded in national health and administrative registries, to assess clinical effectiveness and safety of treatments. We estimated positive predictive values (PPVs) of International Classification of Diseases, 10th revision (ICD-10) codes for primary diagnoses of dermatologic events and hypersensitivity recorded at hospitalization or emergency room visit in the national patient registries of Denmark and Sweden among women with postmenopausal osteoporosis (PMO). Methods This validation study included women with PMO identified from the Danish and Swedish national patient registries (2005–2014). Medical charts of the potential cases served as the gold standard for the diagnosis confirmation and were reviewed and adjudicated by physicians. Results We obtained and reviewed 189 of 221 sampled medical records (86%). The overall PPV was 92.4% (95% confidence interval [CI], 85.1%–96.3%) for dermatologic events, while the PPVs for bullous events and erythematous dermatologic events were 52.5% (95% CI, 37.5%–67.1%) and 12.5% (95% CI, 2.2%–47.1%), respectively. The PPV was 59.0% (95% CI, 48.3%–69.0%) for hypersensitivity; however, the PPV of hypersensitivity increased to 100.0% (95% CI, 67.6%–100.0%) when restricting to diagnostic codes for anaphylaxis. The overall results did not vary by country. Conclusion Among women with PMO, the PPV for any dermatologic event recorded as the primary diagnosis at hospitalization or at an emergency room visit was high and acceptable for epidemiologic research in the Danish and Swedish national patient registries. The PPV was substantially lower for hypersensitivity leading to hospitalization or emergency room visit.