100 YEARS OF VITAMIN D: Combined hormonal contraceptives and vitamin D metabolism in adolescent girls.

Objective: Combined hormonal contraceptive (CHC) use has been associated with higher total 25-hydroxyvitamin D (25(OH)D) levels. Here, we investigate the relation between CHC use and vitamin D metabolism to elucidate its clinical interpretation. Methods: The cross-sectional Fit Futures 1 included 1038 adolescents. Here, a subgroup of 182 girls with available 25(OH)D, 1,25-dihydroxyvitamin D (1,25(OH)2D), 24,25-dihydroxyvitamin D (24,25(OH)2D), vitamin D-binding protein (DBP) and measured free 25(OH)D levels, in addition to parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23), was investigated. Vitamin D metabolites were compared between girls using (CHC+) and not using CHC (CHC-). Further, the predictability of CHC on 25(OH)D levels was assessed in a multiple regression model including lifestyle factors. The ratios 1,25(OH)2D/25(OH)D and 24,25(OH)2D/25(OH)D (vitamin D metabolite ratio (VMR)) in relation to 25(OH)D were presented in scatterplots. Results: CHC+ (n = 64; 35% of the girls) had higher 25(OH)D levels (mean ± s.d., 60.3 ± 22.2) nmol/L) than CHC- (n = 118; 41.8 ± 19.3 nmol/L), P -values <0.01. The differences in 25(OH)D levels between CHC+ and CHC- were attenuated but remained significant after the adjustment of lifestyle factors. CHC+ also had higher levels of 1,25(OH)2D, 24,25(OH)2D, DBP and calcium than CHC-, whereas 1,25(OH)2D/25(OH)D, PTH, FGF23 and albumin were significantly lower. Free 25(OH)D and VMR did not statistically differ, and both ratios appeared similar in relation to 25(OH)D, irrespective of CHC status. Conclusion: This confirms a clinical impact of CHC on vitamin D levels in adolescents. Our observations are likely due to an increased DBP-concentration, whereas the free 25(OH)D appears unaltered.

Vitamin D supplementation has no effect on cognitive performance after four months in mid-aged and older subjects.

BACKGROUND: Low serum 25-hydroxyvitamin D (25(OH)D) levels are associated with impaired cognitive function, but the effect of vitamin D supplementation on cognitive function is uncertain. METHODS: 422 subjects were included in a randomized controlled trial with vitamin D (cholecalciferol) 100,000 IU given as a bolus dose followed by 20,000 IU per week versus placebo for four months. Cognitive function was evaluated with verbal recall test, coding test and tapping test. RESULTS: 374 subjects (mean age 52 years, 198 males) had complete cognitive tests both at baseline and at end of study. Mean baseline serum 25(OH)D level was 34 nmol/L. At baseline there were no significant associations between serum 25(OH)D and the three separate cognitive tests. At the end of the study mean serum 25(OH)D levels were 89 nmol/L and 31 nmol/L in the vitamin D and placebo groups, respectively. At the end of the study, there were no statistically significant differences between the two groups regarding change in the cognitive test scores. Nor did sub-group analyses based on gender, age, baseline serum 25(OH)D and cognitive test scores reveal significant differences between the two groups at the end of the study. CONCLUSIONS: Vitamin D supplementation did not improve cognitive function during a four months intervention in mid-aged and older subjects. TRIAL REGISTRATION: ClinicalTrials.govNCT02750293.

Cortisol levels and cognitive profile in major depression: A comparison of currently and previously depressed patients.

The association between depressive symptoms and elevated cortisol levels, and depression and cognitive functioning, has been less robust in outpatients with symptoms in the mild to moderate range. Furthermore, the association between elevated cortisol levels and cognitive functioning is unclear. In the present study, currently depressed (n = 37), previously depressed (n = 81) and never depressed controls (n = 50) were assessed on a range of neuropsychological measures. Salivary cortisol was measured in the morning and evening. Participants with current depression were non-hospitalized and had symptoms predominately in the mild to moderate range. Elevated salivary evening cortisol, but not morning cortisol, was significantly related to depressive symptoms. The difference in cortisol levels between the previously depressed group and the never depressed controls was not significant. The groups had significantly different cognitive profiles, with the currently depressed performing poorer on tasks related to working memory compared to the never depressed controls. Both the currently and previously depressed performed worse on attentional tasks. The findings indicate that outpatients with mild to moderate depression have elevated cortisol levels and limited mild cognitive impairments. Furthermore, mild impairments in attention may persist after remission, indicating that this could be a trait-marker in depression. The present study did not find support for a significant relationship between cortisol and cognitive functioning.

Failure to Find a Conditioned Placebo Analgesic Response.

Background: Associative learning has, in several studies, been modulated by the sex of the participant. Consistent with this, a recent review found that conditioned nocebo effects are stronger in females than in males. Purpose: It has been suggested that conditioned placebo responses are stronger in females, and this hypothesis was investigated in the present study. Cortisol and measures of negative emotions were taken to investigate if these processes could mediate any conditioned placebo effects. Methods: Cold pain was applied to the volar forearm. The Conditioned group received inert capsules prior to two presentations of less painful stimulations, to associate intake of the capsules with reduced pain. The pain control group received the same painful stimulation as the Conditioned group, but no capsules. The Capsule control group received the capsules in the same way as the Conditioned group, but no decrease in the painful stimulation. Participant sex was crossed across groups. It was hypothesized that in the Conditioned group, an expectation of reduced pain should be induced after administration of the capsules, and this should generate placebo analgesia, and mostly so in females. Results: The Conditioned group reported lower pain during conditioning, and rated the capsules as more effective painkillers than the capsule control group. However, placebo analgesia was not reliably observed in the Conditioned group. Conclusion: The placebo capsules were rated as effective painkillers, but this did not translate into a placebo analgesic effect. This could be due to violation of response expectancies, too few conditioning trials, and differences in pain ratings in the pre-test that could be due to previous experience with painkillers.

Co-expression of 1α-hydroxylase and vitamin D receptor in human articular chondrocytes.

BACKGROUND: The aim was to investigate whether resident chondrocytes in human articular cartilage and in subculture express vitamin D receptor (VDR) and the enzyme that hydroxylates the prohormone 25(OH)D3 to the active hormone 1α,25(OH)2D3, namely 1α-hydroxylase (CYP27B1). Any putative effects of vitamin D on chondrocytes were also explored. METHODS: Cartilage from human osteoarthritic knee joints, cultured chondrocytes and cells grown in 3D spheroids were examined for the expression of VDR and 1α-hydroxylase by PCR, Western blots and immunolabelling. Receptor engagement was judged by visualizing nuclear translocation. The effects of 25(OH)D3 and 1α,25(OH)2D3 on chondrocyte functions were assessed in proliferation-, chondrogenesis- and cartilage signature-gene expression assays. The capability of chondrocytes to hydroxylate 25(OH)D3 was determined by measuring the concentration of metabolites. Finally, a putative regulation of receptor and enzyme expression by 1α,25(OH)2D3 or interleukin (IL)-1ß, was investigated by Western blot. RESULTS: Gene expression was positive for VDR in freshly isolated cells from native cartilage, cells subcultured in monolayers and in spheroids, whereas protein expression, otherwise judged low, was apparent in monolayers. Nuclear translocation of VDR occurred upon 1α,25(OH)2D3 treatment. Transcripts for 1α-hydroxylase were detected in freshly isolated cells, cultured cells and spheroids. Western blots and immunolabelling detected 1α-hydroxylase protein in all materials, while staining of tissue appeared confined to cells at the superficial layer. A dose-dependent 1α,25(OH)2D3 production was measured when the enzyme substrate was supplied to cell cultures. Western blots revealed that the VDR, but not 1α-hydroxylase, was induced by IL-1ß treatment in adherent cells. Proliferation in monolayers was enhanced by both 25(OH)D3 and 1α,25(OH)2D3, and both compounds had negative effects on chondrogenesis and cartilage-matrix genes. CONCLUSIONS: VDR expression in resident cartilage chondrocytes, generally considered differentiated cells, is elusive. A similar pattern applies for redifferentiated chondrocytes in spheroid cultures, whereas dedifferentiated cells, established in monolayers, stably express VDR. Both 25(OH)D3 and 1α,25(OH)2D3 are able to potentiate cell proliferation but have a negative impact in proteoglycan synthesis. Chondrocytes express 1α-hydroxylase and may contribute to the production of 1α,25(OH)2D3 into the joint environment. Effects of vitamin D could be unfavourable in the context of cartilage matrix synthesis.

The role of formyl peptide receptor 1 (FPR1) in neuroblastoma tumorigenesis.

BACKGROUND: Formyl peptide receptor 1 (FPR1) is a G protein-coupled receptor mainly expressed by the cells of myeloid origin, where it mediates the innate immune response to bacterial formylated peptides. High expression of FPR1 has been detected in various cancers but the function of FPR1 in tumorigenesis is poorly understood. METHODS: Expression of FPR1 in neuroblastoma cell lines and primary tumors was studied using RT-PCR, western blotting, immunofluorescence and immunohistochemistry. Calcium mobilization assays and western blots with phospho-specific antibodies were used to assess the functional activity of FPR1 in neuroblastoma. The tumorigenic capacity of FPR1 was assessed by xenografting of neuroblastoma cells expressing inducible FPR1 shRNA, FPR1 cDNA or control shRNA in nude mice. RESULTS: FPR1 is expressed in neuroblastoma primary tumors and cell lines. High expression of FPR1 corresponds with high-risk disease and poor patient survival. Stimulation of FPR1 in neuroblastoma cells using fMLP, a selective FPR1 agonist, induced intracellular calcium mobilization and activation of MAPK/Erk, PI3K/Akt and P38-MAPK signal transduction pathways that were inhibited by using Cyclosporin H, a selective receptor antagonist for FPR1. shRNA knock-down of FPR1 in neuroblastoma cells conferred a delayed xenograft tumor development in nude mice, whereas an ectopic overexpression of FPR1 promoted augmented tumorigenesis in nude mice. CONCLUSION: Our data demonstrate that FPR1 is involved in neuroblastoma development and could represent a therapy option for the treatment of neuroblastoma.

Vitamin D 20,000 IU per Week for Five Years Does Not Prevent Progression From Prediabetes to Diabetes.

CONTEXT: Vitamin D deficiency is associated with insulin resistance and risk of future diabetes. OBJECTIVE: The objective of the study was to test whether supplementation with vitamin D to subjects with prediabetes will prevent progression to type 2 diabetes mellitus (T2DM). DESIGN: This was a randomized controlled trial performed in 2008 through 2015. SETTING: The study was conducted at the clinical research unit at a teaching hospital. PATIENTS: Five hundred eleven subjects (mean age 62 y, 314 males) with prediabetes diagnosed with an oral glucose tolerance test as part of the Tromsø Study 2007­2008 were included. A total of 256 were randomized to vitamin D and 255 to placebo. Twenty-nine subjects in the vitamin D and 24 in the placebo group withdrew because of adverse events. INTERVENTIONS: Interventions included vitamin D (cholecalciferol) 20 000 IU/wk vs placebo for 5 years. Annual oral glucose tolerance tests were performed. MAIN OUTCOME MEASURE: Progression to T2DM was the main outcome measure. Secondary outcomes were change in glucose levels, insulin resistance, serum lipids, and blood pressure. RESULTS: The mean baseline serum 25-hydroxyvitamin D level was 60 nmol/L (24 ng/mL). One hundred three in the vitamin D and 112 in the placebo group developed T2DM (hazard risk 0.90; 95% confidence interval 0.69­1.18, Cox regression, P = .45, intention to treat analysis). No consistent significant effects on the other outcomes were seen. Subgroup analyses in subjects with low baseline 25-hydroxyvitamin D yielded similar results. No serious side effects related to the intervention were recorded. CONCLUSIONS: In subjects without vitamin D deficiency, vitamin D supplementation is unlikely to prevent progression from prediabetes to diabetes. Very large studies with inclusion of vitamin D-deficient subjects will probably be needed to show such a putative effect. This study tested if supplementation with vitamin D to subjects with prediabetes will prevent progression to type 2 diabetes (T2DM).

Effects of vitamin D binding protein phenotypes and vitamin D supplementation on serum total 25(OH)D and directly measured free 25(OH)D.

OBJECTIVE: To determine the relationship between serum total 25-hydroxyvitamin D (25(OH)D), directly measured free 25(OH)D and calculated free 25(OH)D with regard to vitamin D-binding protein (DBP) phenotypes, sex, BMI, age and season, and their interrelationship to vitamin D supplementation. DESIGN, PATIENTS AND INTERVENTIONS: A randomized controlled trial with 20 000 IU of vitamin D3 per week or placebo for 12 months was designed. A total of 472 subjects, 236 in each of the intervention groups, were included in the analyses. MAIN OUTCOME MEASURES: Baseline serum concentrations and increases in serum total 25(OH)D, directly measured free 25(OH)D, calculated free 25(OH)D and DBP. RESULTS: Serum total 25(OH)D and DBP concentrations were significantly lower in subjects with the phenotype Gc2/Gc2 compared to phenotypes with the Gc1S allele, and lower in males compared to females. When using directly measured free 25(OH)D, the differences related to DBP phenotypes and sexes were clearly diminished. All calculated free 25(OH)D concentrations were overestimated compared to the directly measured free 25(OH)D. Serum parathyroid hormone showed an inverse correlation with all vitamin D parameters analyzed. The increases after 12 months of vitamin D supplementation were not significantly different for any of the vitamin D parameters regardless of DBP phenotype, sex or age. Supplementation with vitamin D did not affect serum DBP. CONCLUSION: Direct measurements of free 25(OH)D reduce the differences seen in total 25(OH)D between DBP phenotype groups and sexes, probably caused by differences in DBP concentrations. With conditions affecting serum DBP concentrations, direct measurements of free 25(OH)D should be considered.

Human articular chondrocytes express functional leukotriene B4 receptors.

Leukotriene B4 (LTB4) is a potent chemoattractant associated with the development of osteoarthritis (OA), while its receptors BLT1 and BLT2 have been found in synovium and subchondral bone. In this study, we have investigated whether these receptors are also expressed by human cartilage cells and their potential effects on cartilage cells. The expression of LTB4 receptors in native tissue and cultured cells was assessed by immunohistochemistry, immunocytochemistry, polymerase chain reaction (PCR) and electron microscopy. The functional significance of the LTB4 receptor expression was studied by Western blotting, using phospho-specific antibodies in the presence or absence of receptor antagonists. In further studies, the secretion of pro-inflammatory cytokines, growth factors and metalloproteinases by LTB4-stimulated chondrocytes was measured by multiplex protein assays. The effects of LTB4 in cartilage signature gene expression in cultured cells were assessed by quantitative PCR, whereas the LTB4-promoted matrix synthesis was determined using 3D pellet cultures. Both receptors were present in cultured chondrocytes, as was confirmed by immunolabelling and PCR. The relative quantification by PCR demonstrated a higher expression of the receptors in cells from healthy joints compared with OA cases. The stimulation of cultured chondrocytes with LTB4 resulted in a phosphorylation of downstream transcription factor Erk 1/2, which was reduced after blocking BLT1 signalling. No alteration in the secretion of cytokine and metalloproteinases was recorded after challenging cultured cells with LTB4; likewise, cartilage matrix gene expression and 3D tissue synthesis were unaffected. Chondrocytes express BLT1 and BLT2 receptors, and LTB4 activates the downstream Erk 1/2 pathway by engaging the high-affinity receptor BLT1. However, any putative role in cartilage biology could not be revealed, and remains to be clarified.

No effect of high-dose vitamin D supplementation on glycemic status or cardiovascular risk factors in subjects with prediabetes.

OBJECTIVE: In observational studies, low serum 25-hydroxyvitamin D [25(OH)D] concentrations have been associated with insulin resistance and other risk factors for cardiovascular disease. RESEARCH DESIGN AND METHODS: We present 1-year data from an ongoing 5-year trial in 511 individuals with impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) randomly assigned to 20,000 IU/week vitamin D3 or placebo. An oral glucose tolerance test was performed at baseline and after 1 year. RESULTS: Mean baseline serum 25(OH)D was 59.9 nmol/L and 61.1 nmol/L in the vitamin D and placebo groups, respectively, and increased by 45.8 nmol/L and 3.4 nmol/L, respectively. With adjustment for baseline concentrations, no differences in measures of glucose metabolism, insulin secretion or sensitivity, blood pressure, or hs-CRP were found after 1 year. There was a slight, but significant decrease in total and LDL cholesterol in the vitamin D group compared with the placebo group, but as there was also a decrease in HDL cholesterol, the change in the total/HDL cholesterol ratio did not differ significantly. Only analyzing subjects with 25(OH)D <50 nmol/L did not change the results. CONCLUSIONS: This study shows that vitamin D supplementation does not improve glycemic indices, blood pressure, or lipid status in subjects with IFG and/or IGT.

Serum free and bio-available 25-hydroxyvitamin D correlate better with bone density than serum total 25-hydroxyvitamin D.

In the circulation 25-hydroxyvitamin D (25(OH)D) is bound to vitamin D-binding protein (DBP) and albumin. Only a small fraction is in the unbound, free form. According to the 'free-hormone-hypothesis' only the free form is biologically active. Genetic differences in DBP may affect the binding to 25(OH)D and thereby the amount of free 25(OH)D. In the present study sera were obtained from 265 postmenopausal women with low bone mass density (BMD). Serum 25(OH)D, DBP and albumin were measured and the free and bio-available (free + albumin-bound) 25(OH)D calculated. Based on genotyping of the polymorphisms rs7041 and rs4588, the six common DBP phenotypes were identified and the free and bio-available 25(OH)D calculated according to the corresponding binding coefficients. Relations between measures of 25(OH)D and PTH and BMD were evaluated with linear regression adjusted for age and BMI. The calculated amount of free and bio-available 25(OH)D was 0.03% and 13.1%, respectively, of the measured total serum 25(OH)D. Adjusting for DBP phenotype affected the calculated free and bio-available 25(OH)D levels up to 37.5%. All measures of 25(OH)D correlated significantly with PTH, whereas a significant association with BMD was only seen for the free and bio-available 25(OH)D measures. Adjusting for the DBP phenotypes improved the associations. These relations were almost exclusively seen in subjects not using vitamin D and/or calcium supplements. In conclusion, the free and bio-available forms of 25(OH)D may be a more informative measure of vitamin D status than total 25(OH)D. Adjustment for DBP phenotype may improve this further.

The phosphodiesterase 8B gene rs4704397 is associated with thyroid function, risk of myocardial infarction, and body height: the Tromsø study.

OBJECTIVE: High serum thyrotropin (TSH) levels predict cardiovascular disease (CVD). Recently several single nucleotide polymorphisms (SNPs) associated with TSH levels have been identified, one of them being the rs4704397 SNP in the phosphodiesterase 8B (PDE8B) gene. If the relation between thyroid function and CVD is causal, one could also expect rs4704397 genotypes to predict CVD and possibly health in general. METHODS: DNA was prepared and genotyping performed for rs4704397 in subjects who participated in the fourth survey of the Tromsø Study in 1994-1995 and who were registered with the endpoints myocardial infarction (MI), type 2 diabetes (T2DM), cancer, or death, as well as a randomly selected control group. Similarly, genotyping was performed in subjects who had participated in clinical trials where serum TSH, free T4 (fT4), and free T3 (fT3) were measured. RESULTS: From the Tromsø Study, 8938 subjects without thyroid disease or thyroid medication were successfully genotyped for rs4704397. Among these, 2098 were registered with MI, 1025 with T2DM, 2748 with cancer, and 3592 had died. The minor homozygote genotype (A:A) had a median serum TSH level that was 0.29 mIU/L higher than in the major homozygote genotype (G:G). The A:A genotype had a significantly increased risk of MI as compared to the G:G genotype (1.14 [1.00-1.29], hazard ratio [confidence interval], Cox regression with adjustment for age, sex, and body mass index). No significant associations were seen with the other endpoints or CVD risk factors. Furthermore, subjects with the G:G genotype were significantly taller than subjects with the A:A genotype (mean difference 1.5 cm). In 584 subjects with serum TSH, fT4, and fT3 measurements, the subjects with the A:A genotype had significantly higher serum TSH and nonsignificantly lower serum fT3 (mean difference 0.15 pmol/L) levels than subjects with the G:G genotype. CONCLUSION: rs4704397 is associated with thyroid function, risk of MI, and body height. However, confirmation in other cohorts is needed before firm conclusions can be drawn.

Serum calcium and the calcium-sensing receptor polymorphism rs17251221 in relation to coronary heart disease, type 2 diabetes, cancer and mortality: the Tromsø Study.

Serum calcium measured in 27,158 subjects in 1994 and the calcium-sensing receptor polymorphism rs17251221 genotyped in 9,404 subjects were related to cardiovascular risk factors, incident myocardial infarction (MI), type 2 diabetes (T2DM), cancer and death during follow-up until 2008-2010. In a Cox regression model with adjustment for age, gender, smoking and body mass index, subjects with serum calcium 2.50-2.60 mmol/L had a significantly increased risk of incident MI [n = 1,802, hazards ratio (HR) 1.40, 95 % confidence interval (CI) 1.18, 1.66] and T2DM (n = 705, HR 1.49, 95 % CI 1.15, 1.94) and a significantly reduced risk of cancer (n = 2,222, HR 0.73, 95 % CI 0.62, 0.86) as compared to subjects with serum calcium 2.20-2.29 mmol/L. For rs17251221 there was a mean difference in serum calcium of 0.05 mmol/L between major and minor homozygote genotypes. No consistent, significant relation between rs17251221 and risk factors or the major hard endpoints were found. The minor homozygote genotype (high serum calcium) had a significant twofold increased risk (HR 2.32, 95 % CI 1.24, 4.36) for prostate cancer, as compared to the major homozygote. This may be clinically important if confirmed in other cohorts.

Effects of Age and Sex on Estimated Diabetes Prevalence Using Different Diagnostic Criteria: The Tromsø OGTT Study.

HbA(1c) 6.5% has recently been recommended as an alternative diagnostic criterion for diabetes. The aims of the study were to evaluate the effects of age, sex, and other factors on prevalence of diabetes and to compare risk profiles of subjects with diabetes when defined by HbA(1c) and glucose criteria. Subjects were recruited among participants in the longitudinal population-based Tromsø Study. HbA(1c), fasting plasma glucose, and 2-hour plasma glucose were measured in 3,476 subjects. In total, 294 subjects met one or more of the diagnostic criteria for diabetes; 95 met the HbA(1c) criterion only, 130 met the glucose criteria only, and 69 met both. Among subjects with diabetes detected by glucose criteria (regardless of HbA(1c)), isolated raised 2-hour plasma glucose was more common in subjects aged ≥ 60 years as compared to younger subjects and in elderly women as compared to elderly men. Subjects with diabetes detected by glucose criteria only had worse cardiometabolic risk profiles than those detected by HbA(1c) only. In conclusion, the current HbA(1c) and glucose criteria defined different subjects with diabetes with only modest overlap. Among a substantial proportion of elderly subjects, and especially elderly women, the 2-hour plasma glucose was the only abnormal value.

Effect of vitamin D supplement on depression scores in people with low levels of serum 25-hydroxyvitamin D: nested case-control study and randomised clinical trial.

AIMS: To compare depressive symptoms in participants with low and high serum 25-hydroxyvitamin D (25(OH)D) levels and to examine whether supplementation with vitamin D(3) would improve symptoms in those with low serum 25(OH)D levels. METHOD: Participants with low 25(OH)D levels were randomised to either placebo or 40 000 IU vitamin D(3) per week for 6 months. Individuals with high serum 25(OH)D levels were used as nested controls. Depressive symptoms were evaluated with the Beck Depression Inventory, Hospital Anxiety and Depression Scale, Seasonal Pattern Assessment Scale and Montgomery-Åsberg Depression Rating Scale. The study was registered at ClinicalTrials.gov (NCT00960232). RESULTS: Participants with low 25(OH)D levels (n = 230) at baseline were more depressed (P<0.05) than participants with high 25(OH)D levels (n = 114). In the intervention study no significant effect of high-dose vitamin D was found on depressive symptom scores when compared with placebo. CONCLUSIONS: Low levels of serum 25(OH)D are associated with depressive symptoms, but no effect was found with vitamin D supplementation.

Polymorphisms related to the serum 25-hydroxyvitamin D level and risk of myocardial infarction, diabetes, cancer and mortality. The Tromsø Study.

OBJECTIVE: Low serum 25(OH)D levels are associated with cardiovascular risk factors, and also predict future myocardial infarction (MI), type 2 diabetes (T2DM), cancer and all-cause mortality. Recently several single nucleotide polymorphisms (SNPs) associated with serum 25-hydroxyvitamin D (25(OH)D) level have been identified. If these relations are causal one would expect a similar association between these SNPs and health. METHODS: DNA was prepared from subjects who participated in the fourth survey of the Tromsø Study in 1994-1995 and who were registered with the endpoints MI, T2DM, cancer or death as well as a randomly selected control group. The endpoint registers were complete up to 2007-2010. Genotyping was performed for 17 SNPs related to the serum 25(OH)D level. RESULTS: A total of 9528 subjects were selected for genetic analyses which were successfully performed for at least one SNP in 9471 subjects. Among these, 2025 were registered with MI, 1092 with T2DM, 2924 with cancer and 3828 had died. The mean differences in serum 25(OH)D levels between SNP genotypes with the lowest and highest serum 25(OH)D levels varied from 0.1 to 7.8 nmol/L. A genotype score based on weighted risk alleles regarding low serum 25(OH)D levels was established. There was no consistent association between the genotype score or individuals SNPs and MI, T2DM, cancer, mortality or risk factors for disease. However, for rs6013897 genotypes (located at the 24-hydroxylase gene (CYP24A1)) there was a significant association with breast cancer (P<0.05). CONCLUSION: Our results do not support nor exclude a causal relationship between serum 25(OH)D levels and MI, T2DM, cancer or mortality, and our observation on breast cancer needs confirmation. Further genetic studies are warranted, particularly in populations with vitamin D deficiency. TRIAL REGISTRATION: ClinicalTrials.gov NCT01395303.

Staphylococcus epidermidis polysaccharide intercellular adhesin activates complement.

Staphylococcus epidermidis is a frequent cause of nosocomial infections. The central virulence factor of S. epidermidis is biofilm formation. Polysaccharide intercellular adhesin (PIA) constitutes the major biofilm matrix-component. PIA and biofilm have been implicated in S. epidermidis evasion of host immune defence. We examined the effects of S. epidermidis PIA on the inflammatory response with focus on complement activation. We used a human whole-blood ex vivo model of infection and compared the effects of a PIA-positive S. epidermidis strain (SE1457) and its PIA-negative isogenic mutant (M10). The independent effect of purified PIA on complement activation was investigated. In glucose-rich media, the mutant formed a proteinacious DNA-rich biofilm, whereas SE1457 formed a thick PIA-biofilm. In biofilm growth, SE1457 induced a stronger activation of the complement system compared with M10. We verified that purified PIA was independently responsible for a strong activation of the complement system. In contrast, M10 induced higher granulocyte activation by expression of CD11b and higher secretion of cytokines. We conclude that PIA has potent pro-inflammatory properties by activating the complement system. However, in a complex balance of the immune response, the decreased activation of granulocytes and cytokines by a PIA biofilm may limit host eradication of S. epidermidis.

Vitamin D, insulin secretion, sensitivity, and lipids: results from a case-control study and a randomized controlled trial using hyperglycemic clamp technique.

OBJECTIVE: Vitamin D deficiency is associated with an unfavorable metabolic profile in observational studies. The intention was to compare insulin sensitivity (the primary end point) and secretion and lipids in subjects with low and high serum 25(OH)D (25-hydroxyvitamin D) levels and to assess the effect of vitamin D supplementation on the same outcomes among the participants with low serum 25(OH)D levels. RESEARCH DESIGN AND METHODS: Participants were recruited from a population-based study (the Tromsø Study) based on their serum 25(OH)D measurements. A 3-h hyperglycemic clamp was performed, and the participants with low serum 25(OH)D levels were thereafter randomized to receive capsules of 20,000 IU vitamin D(3) or identical-looking placebo twice weekly for 6 months. A final hyperglycemic clamp was then performed. RESULTS: The 52 participants with high serum 25(OH)D levels (85.6 ± 13.5 nmol/L [mean ± SD]) had significantly higher insulin sensitivity index (ISI) and lower HbA(1c) and triglycerides (TGs) than the 108 participants with low serum 25(OH)D (40.3 ± 12.8 nmol/L), but the differences in ISI and TGs were not significant after adjustments. After supplementation, serum 25(OH)D was 142.7 ± 25.7 and 42.9 ± 17.3 nmol/L in 49 of 51 completing participants randomized to vitamin D and 45 of 53 randomized to placebo, respectively. At the end of the study, there were no statistically significant differences in the outcome variables between the two groups. CONCLUSIONS: Vitamin D supplementation to apparently healthy subjects with insufficient serum 25(OH)D levels does not improve insulin sensitivity or secretion or serum lipid profile.

Differences in serum levels of CB-153 and p,p'-DDE, and reproductive parameters between men living south and north in Norway.

Arctic is contaminated with persistent organochlorine pollutants (POPs), and exposure to these compounds may differ between south and north in Norway. POPs may have negative impact on male reproductive characteristics. We compared serum levels of the CB-153 and p,p'-DDE in men who were born and had lived most of their lifetime south and north (close to or above the Arctic Circle) in Norway. We found no geographical differences in levels of CB-153 (south: 50 ng/g lipid (mean), north: 59 ng/g lipid; p=0.27) or sperm parameters. However, the levels of p,p'-DDE were higher in south than in north (81 ng/g lipid (mean) vs. 66 ng/g lipid; p=0.02), as were the levels of total and free testosterone. The FSH levels were lowest in south. A strong relationship between the CB-153 and the SHBG levels was observed. The regional differences observed for p,p'-DDE, testosterone and FSH were not reflected in the semen quality.

Variation of serum creatine kinase (CK) levels and prevalence of persistent hyperCKemia in a Norwegian normal population. The Tromsø Study.

In this cross-sectional study we assessed the prevalence of hyperCKemia, defined as persistent CK values ≥210 U/L in women, ≥400 U/L in men <50 years and ≥280 U/L in men ≥50 years (reference values according to the Nordic Reference Interval Project). Blood samples were obtained from 12,828 participants in the 6th survey of The Tromsø Study. We identified 686 (5.3%) individuals with incidentally elevated CK. After a standardized control test, 169 persons (1.3%) had persistent hyperCKemia, i.e. 69.9% normalization. Use of statins or other causes of hyperCKemia were detected in 78 individuals (46.2%), giving a prevalence of "idiopathic hyperCKemia" of 0.71%. CK variation was highest in younger men and in females between 60 and 69 years. This study has identified persistent hyperCKemia in 1.3% of the normal population, and demonstrates the importance of performing controlled CK analyses, also in those with identified risk factors.