Publications (39) View all
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Article: Serum 25-hydroxyvitamin D3 and the risk of pneumonia in an ageing general population.
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ABSTRACT: BACKGROUND: Vitamin D has been suggested to have a role in infection defence and on the immune system. We therefore investigated the effect of serum 25-hydroxyvitamin D3 (25(OH)D3) on the risk of incident hospitalised pneumonia in an ageing general population in eastern Finland. METHODS: The study population included 723 men and 698 women aged 53-73 years from the prospective population-based Kuopio Ischemic Heart Disease Risk Factor study who were free of pneumonia, other pulmonary diseases and cancer at baseline in 1998-2001. Incident pneumonia episodes leading to hospitalisation were collected by record linkage to the hospital discharge register. The serum vitamin D status was assayed as 25(OH)D3 concentration. Cox proportional hazards regression models were used to analyse the effect of serum 25(OH)D3 on the risk of incident pneumonia. RESULTS: The mean (SD) serum 25(OH)D3 concentration of the study population was 43.5 (17.8) nmol/l. 73 subjects had at least one hospitalisation episode due to pneumonia during an average follow-up of 9.8 years. After multivariable adjustments, the subjects in the lowest serum 25(OH)D3 tertile had a 2.6-fold (95% CI 1.4 to 5.0, p trend across tertiles=0.005) higher risk of developing pneumonia compared with the subjects in the highest tertile. This significant result remained even after adjustment for the determinants of serum 25-hydroxyvitamin D3. CONCLUSIONS: These data suggest an inverse effect of serum 25(OH)D3 concentration on the risk of incident pneumonia in the general ageing population.Journal of epidemiology and community health 04/2013; · 3.04 Impact Factor -
Article: HPLC and coulometric electrode array detector in serum 25-hydroxyvitamin D(3) and 25-hydroxyvitamin D(2) analyses.
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ABSTRACT: The diode array detector in our HPLC method for 25-hydroxyvitamin D(3) (25OHD(3)) and 25-hydroxyvitamin D(2) (25OHD(2)) did not perform satisfactory for measuring human serum concentrations below 30 nM. Because of a need for reliable self-managed method in ongoing and starting vitamin D studies of the laboratory, we decided to develop a chromatographic method applying coulometric electrode array detector (CEAD), and evaluate reliability of the method by participating in the vitamin D External Quality Assessment Scheme (DEQAS). The limit of quantification for 25OHD(3) and 25OHD(2) of the new method was 0.36 pmol on column (3.6 nM) and linearity ranged from 5 to 2400 nM. Accuracy of the method was 90% for 25OHD(3) and 69% for 25OHD(2). The HPLC-CEAD results from five DEQAS rounds were in line with the other participating laboratories using HPLC methods. The HPLC-CEAD results for 25OHD(3) corresponded also to the results obtained with the Chromsystems HPLC method in a certified laboratory. The long-term coefficients of variation for 25OHD(3) were 6.2, 7.8, 5.2, 6.7 and 7.3% in concentrations of 27.5, 38.7, 48.4, 78.4 and 88.0 nM, respectively. The developed HPLC-CEAD method was shown to be applicable for determining 25OHD(3) and 25OHD(2) in human serum samples.Analytical Biochemistry 12/2012; · 3.00 Impact Factor -
Article: NMR protocol for determination of oxidation susceptibility of serum lipids and application of the protocol to a chocolate study.
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ABSTRACT: A protocol for determination of oxidation susceptibility of serum lipids based on proton nuclear magnetic resonance ((1)H NMR) spectroscopy is presented and compared to the commonly used spectrophotometric method. Even though there are methodological differences between these two methods, the NMR-based oxidation susceptibility correlates well (r(2) = 0.73) with the lag time determined spectrophotometrically. In addition to the oxidizability of serum lipids, the NMR method provides also information about the lipid profile. The NMR oxidation assay was applied to the chocolate study including fasting serum samples (n = 45) from subjects who had consumed white (WC), dark (DC) or high-polyphenol chocolate (HPC) daily for 3 weeks. The oxidation susceptibility of serum lipids decreased in the HPC group, and there was a significant difference between the WC and HPC groups (P = 0.031). According to the random forest analysis, the consumption of the HPC chocolate induced changes to the amounts of HDL, phosphatidylcholine, sphingomyelin, and nervonic, docosahexaenoic and myristic acids. Furthermore, arachidonic, docosahexaenoic, docosapentaenoic and palmitic acids, gamma-glutamyl transferase, hemoglobin, HDL, phosphatidylcholine and choline containing phospholipids explained about 60% of the oxidation susceptibility values. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11306-011-0323-2) contains supplementary material, which is available to authorized users.Metabolomics 06/2012; 8(3):386-398. · 4.51 Impact Factor -
Article: Association of serum 25-hydroxyvitamin D with type 2 diabetes and markers of insulin resistance in a general older population in Finland.
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ABSTRACT: Vitamin D insufficiency and type 2 diabetes are both common in Finland, and low vitamin D status has been suggested as a risk factor for type 2 diabetes. Our aim was to study the associations between serum 25-hydroxyvitamin D [25(OH)D], a marker of vitamin D status, and glucose homeostasis and type 2 diabetes in a general population sample in Eastern Finland. Cross-sectional analysis in the Kuopio Ischaemic Heart Disease Risk Factor Study. A total of 850 men and 906 women, aged 53-73 years, were analysed. Relative risk (RR) of prevalent diabetes was estimated as odds ratios by logistic regression. Associations between serum 25(OH)D and markers of impaired glucose metabolism in tertiles of serum 25(OH)D concentration were assessed by linear regression. The mean serum 25(OH)D concentration was 43.4 nmol/L (SD 17.6, range 8.5-122.8 nmol/L) in the study population. Serum 25(OH)D concentration <50 nmol/L were observed in 65.5% of the participants. Serum 25(OH)D was inversely associated with fasting serum insulin, fasting blood glucose and oral glucose tolerance test (OGTT) 2-h glucose levels after adjustment for age, gender and examination year. Association with the OGTT 2-h glucose remained statistically significant after multivariate adjustments. The RR (95% confidence interval) for type 2 diabetes in tertiles of serum 25(OH)D were 1, 1.26 (0.86, 1.85) and 1.44 (0.96, 2.15) after multivariate adjustments (p for trend = 0.08). Our results suggest that low serum 25(OH)D is associated with impaired glucose and insulin metabolism.Diabetes/Metabolism Research and Reviews 02/2012; 28(5):418-23. · 3.37 Impact Factor -
Article: A single dose of enterolactone activates estrogen signaling and regulates expression of circadian clock genes in mice.
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ABSTRACT: Enterolactone (EL) is an enterolignan produced by gut microbiota from dietary plant lignans. Epidemiological and experimental studies suggest that EL and plant lignans may reduce the risk of breast and prostate cancer as well as cardiovascular disease. These effects are thought to at least in part involve modulation of estrogen receptor activity. Surprisingly little is known about the in vivo estrogenicity of EL. In the present study, we investigated the target tissues of EL, the genes affected by EL treatment, and the response kinetics. Following a single dose of EL, luciferase was significantly induced in reproductive and nonreproductive tissues of male and female 3xERE-luciferase mice, indicating estrogen-like activity. Microarray analysis revealed that EL regulated the expression of only 1% of 17β-estradiol target genes in the uterus. The majority of these genes were traditional estrogen target genes, but also members of the circadian signaling pathway were affected. Kinetic analyses showed that EL undergoes rapid phase II metabolism and is efficiently excreted. In vivo imaging demonstrated that the estrogen response followed similar, fast kinetics. We conclude that EL activates estrogen signaling in both male and female mice and that the transient responses may be due to the fast metabolism of the compound. Lastly, EL may represent a link among diet, gut microbiota, and circadian signaling.Journal of Nutrition 09/2011; 141(9):1583-9. · 3.92 Impact Factor
