Multiplicative, additive, and interactive associations of 25-hydroxyvitamin D with lung and prostate cancer.

Results regarding the epidemiological association of vitamin D with lung (LCA) and prostate cancer (PCA) are controversial. This study tested whether serum 25-hydroxyvitamin D [25(OH)D] concentrations have interactive epidemiological associations with smoking, the number-one risk factor for LCA, and age, the number-one risk factor for PCA. Also, this study investigated whether the associations of 25(OH)D, smoking, age, alcohol consumption, body mass index, diet (the healthy Nordic diet score), and physical activity with incident LCA and PCA are multiplicative or additive. The study of association types makes it easier to select appropriate statistical methods. The Kuopio Ischaemic Heart Disease Risk Factor Study provided the data of 2578 men with 112 LCA and 300 PCA cases over 35 years by the end of 2019. Serum 25(OH)D did not associate with LCA and PCA or interact with smoking and age. The association of smoking with LCA was additive; 13 extra cases per 1000 men every 10 years. Age and alcohol consumption multiplicatively increased the hazard of LCA (hazard ratio, 95% confidence interval for age >50: 3.56, 1.82-6.17; drink per week: 1.01, 1.00-1.03), whereas adherence to healthy Nordic diet decreased it (per score point: 0.95, 0.89-1.00). The association of age >50 with PCA was additive; 2.5 extra cases per 1000 men every 10 years. To conclude, there was no epidemiological relationship of pre-diagnostic 25(OH)D concentrations with the incidence of LCA and PCA. The respective associations of smoking and age >50 with LCA and PCA were additive rather than multiplicative.

The effect of vitamin D3 supplementation on atrial fibrillation in generally healthy men and women: The Finnish Vitamin D Trial.

Atrial fibrillation is a common cardiac arrhythmia with high morbidity risk. Observational studies suggest that vitamin D deficiency is associated with higher atrial fibrillation risk but there is limited evidence whether vitamin D supplementation could affect the risk. In these post hoc analyses from the Finnish Vitamin D Trial, we compared the incidence of atrial fibrillation with 5-year supplementation of vitamin D3 (1600 IU/d or 3200 IU/d) vs placebo. CLINICAL TRIAL REGISTRY NUMBER: ClinicalTrials.gov: NCT01463813, https://clinicaltrials.gov/ct2/show/NCT01463813.

How competing risks affect the epidemiological relationship between vitamin D and prostate cancer incidence? A population-based study.

We hypothesized that controversial results regarding the epidemiological relationship between circulating 25-hydroxyvitamin D, 25(OH)D, and risk of prostate cancer (PCA) incidence are partly due to competing risks. To test the hypothesis, we studied associations across 25(OH)D, PCA and death in 2578 middle-aged men belonging to the Kuopio Ischaemic Heart Disease Risk Factor Study. The men were free of cancer at baseline, and the mean (SD) follow-up time was 23.3 (9.1) years. During this period, 296 men had a PCA diagnosis, and 1448 men died without the PCA diagnosis. The absolute risk of developing PCA was highest in the highest 25(OH)D tertile (15%), whereas that of death was highest in the lowest 25(OH)D tertile (67%). A competing risk analysis showed that belonging to the highest 25(OH)D tertile increased the risk of PCA incidence and improved survival with the respective hazard ratios (HR) of 1.35 (95% CI = 1.07-1.70) and 0.79 (95% CI = 0.71-0.89). Adjusting for 10 covariates together with 25(OH)D did not significantly change the results, but the respective adjusted HRs for PCA and death were 1.20 and 0.87. To conclude, the competing risk analysis did not eliminate the direct relationship between 25(OH)D and PCA but rather strengthened it.

Follicle-Stimulating Hormone Levels and Subclinical Atherosclerosis in Older Postmenopausal Women.

Recent studies of perimenopausal women suggest that follicle-stimulating hormone (FSH) levels may be associated with atherosclerosis, independent of estradiol. Whether FSH is related to atherosclerosis in older postmenopausal women, who have completed the menopausal transition, remains unknown. We assessed the relationship of serum FSH and estradiol levels with carotid artery intima-media thickness (IMT) among 587 postmenopausal participants in the Kuopio Ischemic Heart Disease Risk Factor Study (Kuopio, Finland). Participants were aged 53-73 years and not using hormone therapy at baseline (1998-2001). Mean IMT was measured via high-resolution ultrasonography. We observed a significant inverse association between FSH levels and IMT. Mean IMTs among women in quartiles 1-4 of FSH were 0.94 mm, 0.91 mm, 0.87 mm, and 0.85 mm, respectively (P-trend < 0.001). After adjustment for age, estradiol, testosterone, body mass index (weight (kg)/height (m)2), lipids, and other factors, FSH levels remained significantly associated with IMT (regression coefficients for quartiles 2-4 vs. quartile 1 were -0.038, -0.045, and -0.062, respectively; P-trend = 0.01). Findings were strongest in women aged 64-73 years (P-trend = 0.006) and did not vary by body mass index. In contrast, estradiol levels were not related to IMT. In summary, high postmenopausal FSH levels were associated with a lower atherosclerotic burden, independent of estradiol, adiposity, and other factors. Our findings warrant replication and the further exploration of potential underlying mechanisms.

The association between serum 25-hydroxyvitamin D3 concentration and risk of disease death in men: modification by magnesium intake.

Low vitamin D status increases the risk of death. Magnesium plays an essential role in vitamin D metabolism and low magnesium intake may predispose to vitamin D deficiency and potentiate the health problems. We investigated whether magnesium intake modifies the serum 25(OH)D3 concentration and its associations with mortality in middle-aged and older men. We included 1892 men aged 42-60 years without cardiovascular disease or cancer at baseline in 1984-1989 from the prospective, population-based Kuopio Ischaemic Heart Disease Risk Factor Study. Serum 25(OH)D3 was measured with the high-performance liquid chromatography using coulometric electrode array detection. Magnesium intake was assessed with 4-day food recording. Deaths were ascertained by a computer linkage to the national cause of death register. Deaths due accidents and suicides were excluded. Cox proportional hazards regression models were used to analyze the associations. The multivariate-adjusted hazard ratio (HR) for death in the lowest (<32.1 nmol/L) versus the highest (>49.4 nmol/L) serum 25(OH)D3 tertile was 1.31 (95 % CI 1.07-1.60, Ptrend = 0.01). Stratified by the magnesium intake, the higher risk was observed only in the lower magnesium intake median (<414 mg/day); HR = 1.60 (95 % CI 1.19-2.13, Ptrend = 0.002) in the lowest versus the highest 25(OH)D3 tertile, whereas the corresponding HR = 1.07, 95 % CI 0.75-1.36, Ptrend = 0.63) in the higher magnesium intake median, P for interaction = 0.08. In this cohort of middle-aged and older men low serum 25(OH)D3 concentration was associated with increased risk of death mainly in those with lower magnesium intake.

High-performance liquid chromatography and coulometric electrode array detector in serum 25-hydroxyvitamin D(3) and 25-hydroxyvitamin D(2) analyses.

The diode array detector in our high-performance liquid chromatography (HPLC) method for 25-hydroxyvitamin D(3) (25OHD(3)) and 25-hydroxyvitamin D(2) (25OHD(2)) did not perform satisfactorily for measuring human serum concentrations below 30nM. Because of a need for a 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 0.36pmol on column (3.6nM), and linearity ranged from 5 to 2400nM. 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 those of the other participating laboratories using HPLC methods. The HPLC-CEAD results for 25OHD(3) also corresponded 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 88.0nM, respectively. The developed HPLC-CEAD method was shown to be applicable for determining 25OHD(3) and 25OHD(2) in human serum samples.

Association of serum 25-hydroxyvitamin D with type 2 diabetes and markers of insulin resistance in a general older population in Finland.

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: Our results suggest that low serum 25(OH)D is associated with impaired glucose and insulin metabolism.

Vitamin D supplementation and prevention of cardiovascular disease and cancer in the Finnish Vitamin D Trial: a randomized controlled trial.

BACKGROUND: Vitamin D insufficiency is associated with risks of cardiovascular diseases (CVD) and cancer in observational studies, but evidence for benefits with vitamin D supplementation is limited. OBJECTIVES: To investigate the effects of vitamin D3 supplementation on CVD and cancer incidences. METHODS: The study was a 5-year, randomized, placebo-controlled trial among 2495 male participants ≥60 years and post-menopausal female participants ≥65 years from a general Finnish population who were free of prior CVD or cancer. The study had 3 arms: placebo, 1600 IU/day, or 3200 IU/day vitamin D3. Follow-up was by annual study questionnaires and national registry data. A representative subcohort of 551 participants had more detailed in-person investigations. The primary endpoints were incident major CVD and invasive cancer. Secondary endpoints included the individual components of the primary CVD endpoint (myocardial infarction, stroke, and CVD mortality), site-specific cancers, and cancer death. RESULTS: During the follow-up, there were 41 (4.9%), 42 (5.0%), and 36 (4.3%) major CVD events in the placebo, 1600 IU/d (compared with placebo: HR: 0.97; 95% CI: 0.63-1.49; P = 0.89), and 3200 IU/d (HR: 0.84; 95% CI: 0.54-1.31; P = 0.44) arms, respectively. Invasive cancer was diagnosed in 41 (4.9%), 48 (5.8%), and 40 (4.8%) participants in the placebo, 1600 IU/d (HR: 1.14; 95% CI: 0.75-1.72; P = 0.55), and 3200 IU/d (HR: 0.95; 95% CI: 0.61-1.47; P = 0.81) arms, respectively. There were no significant differences in the secondary endpoints or total mortality. In the subcohort, the mean baseline serum 25-hydroxyvitamin D concentration was 75 nmol/L (SD, 18 nmol/L). After 12 months, the concentrations were 73 nmol/L (SD, 18 nmol/L), 100 nmol/L (SD, 21 nmol/L), and 120 nmol/L (SD, 22 nmol/L) in the placebo, 1600 IU/d, and 3200 IU/d arms, respectively. CONCLUSIONS: Vitamin D3 supplementation did not lower the incidences of major CVD events or invasive cancer among older adults, possibly due to sufficient vitamin D status in most participants at baseline.

A single dose of enterolactone activates estrogen signaling and regulates expression of circadian clock genes in mice.

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 17ß-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.

Association of serum 25-hydroxyvitamin D with the risk of death in a general older population in Finland.

PURPOSE: To investigate the association between serum 25-hydroxyvitamin D [25(OH)D] concentration, a marker of vitamin D status, and risk of all-cause and cardiovascular mortality in a general older population with relatively low average serum 25(OH)D concentrations. METHODS: The study population included 552 men and 584 women aged 53-73 years who were free of CVD and cancer at baseline in 1998-2001 from the prospective, population-based Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study. Deaths were ascertained by a computer linkage to the national cause of death register. All deaths that occurred from the study entry to December 31, 2008, were included. Cox proportional hazards regression models were used to analyze the association between serum 25(OH)D and risk of death. RESULTS: The mean serum 25(OH)D concentration was 43.7 nmol/L (SD 17.8), with a strong seasonal variation. During the average follow-up of 9.1 years, 87 participants died, 35 from cardiovascular disease (CVD). After multivariable-adjustments, the hazard ratios (HR) for all cause death in the tertiles of serum 25(OH)D were 1, 1.68 (95% CI: 0.92, 3.07) and 2.06 (95% CI: 1.12, 3.80), p for trend = 0.02. CONCLUSIONS: Our study supports the accumulating evidence from epidemiological studies that vitamin D deficiency is associated with increased risk of death. Large-scale primary prevention trials with vitamin D supplementation are warranted.

Elevated circulating LDL phenol levels in men who consumed virgin rather than refined olive oil are associated with less oxidation of plasma LDL.

In human LDL, the bioactivity of olive oil phenols is determined by the in vivo disposition of the biological metabolites of these compounds. Here, we examined how the ingestion of 2 similar olive oils affected the content of the metabolic forms of olive oil phenols in LDL in men. The oils differed in phenol concentrations as follows: high (629 mg/L) for virgin olive oil (VOO) and null (0 mg/L) for refined olive oil (ROO). The study population consisted of a subsample from the EUROLIVE study and a randomized controlled, crossover design was used. Intervention periods lasted 3 wk and were preceded by a 2-wk washout period. The levels of LDL hydroxytyrosol monosulfate and homovanillic acid sulfate, but not of tyrosol sulfate, increased after VOO ingestion (P < 0.05), whereas the concentrations of circulating oxidation markers, including oxidized LDL (oxLDL), conjugated dienes, and hydroxy fatty acids, decreased (P < 0.05). The levels of LDL phenols and oxidation markers were not affected by ROO consumption. The relative increase in the 3 LDL phenols was greater when men consumed VOO than when they consumed ROO (P < 0.05), as was the relative decrease in plasma oxLDL (P = 0.001) and hydroxy fatty acids (P < 0.001). Plasma oxLDL concentrations were negatively correlated with the LDL phenol levels (r = -0.296; P = 0.013). Phenols in LDL were not associated with other oxidation markers. In summary, the phenol concentration of olive oil modulates the phenolic metabolite content in LDL after sustained, daily consumption. The inverse relationship of these metabolites with the degree of LDL oxidation supports the in vivo antioxidant role of olive oil phenolics compounds.

Dietary intake and urinary excretion of lignans in Finnish men.

Intake of lignans has been assessed in different study populations, but so far none of the studies has compared the daily intake of lignans and the urinary excretion of plant and enterolignans. We assessed the intake of lariciresinol, pinoresinol, secoisolariciresinol and matairesinol in 100 Finnish men consuming their habitual omnivorous diet, and measured the 24 h urinary excretion of plant and enterolignans to compare the intake and metabolism. Dietary determinants of lignan intake and their urinary excretion were also determined. The mean intake of lignans was 1224 (sd 539) mug/d, of which lariciresinol and pinoresinol covered 78 %. Almost half (47 %) of the intake of lignans was explained by the intake of rye products, berries, coffee, tea and roots. The urinary excretion of plant lignans corresponded to 17 % and enterolignans to 92 % of the intake of lignans. The urinary excretion of plant lignans was explained 14 % by the intake of rye products and intake of coffee, and consequently 3-7 % by the intake of water-insoluble fibre. The urinary excretion of enterolactone was explained 11 % by the intake of vegetables and rye products, 14 % by the intake of water-soluble fibre and only 4 % by the intake of lariciresinol. Although the assessed intake of lignans corresponded well with the urinary excretion of lignans, the enterolactone production in the human body depended more on the dietary sources of lignans than the absolute intake of lignans.

In vivo transcriptome changes of human white blood cells in response to vitamin D.

In the vitamin D intervention study VitDbol (NCT02063334) blood samples were drawn directly before an oral bolus (2000 µg vitamin D3) and 24 h later. The focus of phase II of VitDbol was the transcriptome-wide analysis of the effects of vitamin D gene expression in human peripheral blood mononuclear cells (PBMCs). All five participants responded in an individual fashion to the bolus by increases in serum levels of the vitamin D metabolites 25-hydroxyvitamin D3 (25(OH)D3) and 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3). RNA sequencing identified 15.040 commonly expressed genes in PBMCs, 702 (4,7%) of which were significantly (p < 0,05) affected by the vitamin D3 bolus. KEGG pathway analysis suggested that these genes are involved in general protein translation, monocyte differentiation and cellular growth control. Previously published transcriptome-wide studies in comparable cell systems confirmed 234 of the 702 vitamin D target genes, leaving many genes, such as HLA-A and HLA-C, as novel discoveries. Interestingly, in vivo stimulated PBMCs of this study showed a larger number of common vitamin D target genes with the monocytic cell line THP-1 than with in vitro stimulated PBMCs. The expression pattern of vitamin D target genes differed significantly between individuals and the average expression change can serve as a marker for vitamin D responsiveness. In conclusion, this study demonstrates that under in vivo conditions changes in 25(OH)D3 and 1,25(OH)2D3 serum concentrations alter the expression of more than 700 vitamin D target genes in human leukocytes.

Metabolic Profiling of High Egg Consumption and the Associated Lower Risk of Type 2 Diabetes in Middle-Aged Finnish Men.

SCOPE: Higher egg intake was previously associated with a lower risk of developing type 2 diabetes (T2D) in the prospective, population-based Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD) in eastern Finland. Potential compounds that can explain this association are explored using nontargeted LC-MS-based metabolic profiling. METHODS AND RESULTS: Two hundred and thirty-nine baseline serum samples from the KIHD are analyzed in four groups: subjects with higher (mean intake one egg per day) or lower (mean intake two eggs per week) egg intake who developed T2D (cases) or remained heatlhy (controls) during the mean follow-up of 19.3 years. Different serum profiles of subjects who had either higher or lower egg intakes, and of those who developed type 2 diabetes or remained healthy, are observed. The higher baseline tyrosine level predicts higher odds of T2D (OR 1.94; 95% CI 1.45, 2.60; p < 0.001; FDR 0.023) along with an unknown hexose-containing compound (OR 2.13; 95% CI 1.57, 2.88; p < 0.001; FDR 0.005). Certain predominant metabolites in T2D cases are correlated positively with ones in the lower-egg-intake group and negatively with ones in the higher-egg-intake group. CONCLUSION: Our current findings may underline some potential metabolites that can explain how egg intake is associated with a lower risk of T2D.

Intake of flavonoids and risk of cancer in Finnish men: The Kuopio Ischaemic Heart Disease Risk Factor Study.

Limited amount of evidence suggests that high intake of flavonoids could be associated with decreased risk of lung and colorectal cancer, but more studies are needed. In this prospective cohort study, we assessed the relation between the intakes of 26 flavonoids from 5 subclasses; flavonols, flavones, flavanones, flavan-3-ols and anthocyanidins, and the risk of lung, prostate and colorectal cancer. The study population consisted of 2,590 middle-aged eastern Finnish men of the prospective population-based Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study. The mean intake of flavonoids was 131.0 +/- 214.7 mg/day. During the mean follow-up time of 16.2 years, 62 lung, 138 prostate, and 55 colorectal cancers occurred. All lung cancer cases occurred among either current smokers (n = 50) or previous smokers (n = 12). After adjustment for age, examination years, body mass index, smoking status, pack-years of smoking, physical activity and intakes of alcohol, total fat, saturated fat, fiber, vitamin C and E, relative risk (RR) for lung cancer was 0.27 (95% CI: 0.11-0.66) for the highest quarter of total flavonoid intake as compared with the lowest quarter. Out of 5 flavonoid subclasses, flavonols and flavan-3-ols were associated with lung cancer, for the highest quarter of intake the RR were 0.29 (95% CI: 0.11-0.78) and 0.24 (95% CI: 0.09-0.64), respectively. No association between flavonoid intake and risk of prostate or colorectal cancer were found. We conclude that high intake of flavonoids is associated with decreased risk of lung cancer in middle-aged Finnish smoking men.

Enterolactone induces heme oxygenase-1 expression through nuclear factor-E2-related factor 2 activation in endothelial cells.

Enterolactone is a lignan formed by enterobacteria from precursors in plant foods. Due to its phenolic structure, it can act as an antioxidant, e.g. via direct scavenging of hydroxyl radical. Moreover, many, but not all, phenolic compounds can have indirect antioxidative effects through induction of heme oxygenase-1 (HO-1), which has antiinflammatory functions via production of antioxidants bilirubin and biliverdin as well as carbon monoxide, thereby contributing to cardiovascular health. Our aim was therefore to assess whether enterolactone has indirect antioxidative effects via induction of HO-1 in endothelial cells. The effect of enterolactone on HO-1 mRNA and protein expression in human umbilical vein endothelial cells (HUVEC) was analyzed by quantitative real-time PCR and western blot. The role of nuclear factor-E2-related factor 2 (Nrf2) in HO-1 induction by enterolactone was studied using small interfering RNA (siRNA) and chromatin immunoprecipitation (ChIP) methods. Our results showed that enterolactone induced HO-1 in HUVEC in a time- and concentration-dependent manner. The induction appeared to be mediated via the transcription factor Nrf2, as Nrf2 siRNA abolished the HO-1 induction by enterolactone. We also showed using ChIP that exposure to enterolactone increased the binding of Nrf2 to the promoter region of HO-1. In conclusion, enterolactone increases the expression of HO-1 via Nrf2, which may contribute to its vasculoprotective effects.

Flavonoid intake and the risk of ischaemic stroke and CVD mortality in middle-aged Finnish men: the Kuopio Ischaemic Heart Disease Risk Factor Study.

The role of flavonoids in CVD, especially in strokes, is unclear. Our aim was to study the role of flavonoids in CVD. We studied the association between the intakes of five subclasses (flavonols, flavones, flavanones, flavan-3-ols and anthocyanidins), a total of twenty-six flavonoids, on the risk of ischaemic stroke and CVD mortality. The study population consisted of 1950 eastern Finnish men aged 42-60 years free of prior CHD or stroke as part of the prospective population-based Kuopio Ischaemic Heart Disease Risk Factor Study. During an average follow-up time of 15.2 years, 102 ischaemic strokes and 153 CVD deaths occurred. In the Cox proportional hazards model adjusted for age and examination years, BMI,systolic blood pressure, hypertension medication, serum HDL- and LDL-cholesterol, serum TAG, maximal oxygen uptake, smoking, family history of CVD, diabetes, alcohol intake, energy-adjusted intake of folate, vitamin E, total fat and saturated fat intake (percentage of energy), men in the highest quartile of flavonol and flavan-3-ol intakes had a relative risk of 0.55 (95% CI 0.31, 0.99) and 0.59 (95% CI 0.30, 1.14) for ischaemic stroke, respectively, as compared with the lowest quartile. After multivariate adjustment, the relative risk for CVD death in the highest quartile of flavanone and flavone intakes were 0.54 (95% CI 0.32, 0.92) and 0.65 (95% CI 0.40, 1.05), respectively. The present results suggest that high intakes of flavonoids may be associated with decreased risk of ischaemic stroke and possibly with reduced CVD mortality.

Simultaneous measurement of retinol, alpha-tocopherol and six carotenoids in human plasma by using an isocratic reversed-phase HPLC method.

A simple and sensitive isocratic reversed-phase high-performance liquid chromatography (HPLC) method for simultaneous determination of retinol, alpha-tocopherol and six carotenoids in human plasma was described. Sample preparation of the earlier published method was further developed by addition of ultrapure water, which enabled aqueous layer to freeze facilitating phase separation without pipetting thus also improving precision of the method. Developed method appeared to be less laborious and time consuming compared to the traditional extraction methods, which require removal of organic layer by pipetting. The recoveries (absolute and relative) were between 80% and 103%. The intra-assay CVs were 1.1-4.0% (normal level) and 3.3-9.0% (low level). Inter-assay CVs were 5.3-8.8%. Reference method for all these analytes was not available, but a comparison with another published method was carried out. The results of the comparison matched satisfactorily. The method is used routinely in our laboratory in a large population-based study.

In vivo response of the human epigenome to vitamin D: A Proof-of-principle study.

In vitro cell culture studies showed that the hormonal form of vitamin D3, 1α,25-dihydroxyvitamin D3, significantly (p < 0.05) affects the human epigenome at thousands of genomic loci. Phase II of the VitDbol vitamin D intervention trial (NCT02063334) involved a proof-of-principle study of one individual, who was exposed three times every 28 days to an oral bolus (2000 µg) of vitamin D3. Blood samples were taken directly before each supplementation as well as one and two days after, chromatin was isolated from peripheral blood mononuclear cells without any further in vitro culture and at all nine time points epigenome-wide chromatin accessibility was assessed by applying FAIRE-seq (formaldehyde-assisted isolation of regulatory elements sequencing). The vitamin D3 bolus resulted in an average raise in 25-hydroxyvitamin D3 (25(OH)D3) serum concentration of 11.9 and 19.4 nM within one and two days, respectively. Consistently accessible chromatin was detected at 5205 genomic loci, the 853 most prominent of which a self-organizing map algorithm classified into early, delayed and non-responding genomic regions: 70 loci showed already after one day and 361 sites after two days significant (p < 0.0001) chromatin opening or closing. Interestingly, more than half of these genomic regions overlap with transcription start sites, but the change of chromatin accessibility at these sites has no direct effect on the transcriptome. Some of the vitamin D responsive chromatin sites cluster at specific loci within the human genome, the most prominent of which is the human leukocyte antigen region in chromosome 6. In conclusion, this study demonstrates that under in vivo conditions a rather minor rise in 25(OH)D3 serum levels is sufficient to result in significant changes at hundreds of sites within the epigenome of human leukocytes.

Serum dihomo-γ-linolenic acid level is inversely associated with the risk of depression. A 21-year follow-up study in general population men.

BACKGROUND: Depression is a major public health challenge worldwide, and polyunsaturated fatty acids (PUFAs), especially n-3 PUFAs, have been found to inversely associate with the risk of depression. However, only few cross-sectional studies have investigated the association between dihomo-γ-linolenic acid (DGLA), an n-6 PUFA with anti-inflammatory effects, and depression. The aims of the present study were to examine an association between serum DGLA and the risk of depression, and to study whether the potential association is mediated via inflammation. METHODS: A 20-year prospective Kuopio Ischaemic Heart Disease Risk Factor (KIHD) follow-up study was conducted from 1984 to 1989 with 2179 middle-aged and older Finnish men (42-60 years old at baseline). The baseline concentrations of serum fatty acids, including DGLA, were determined. A hospital discharge diagnosis of depression was used as the main outcome and obtained from linkage to National Hospital Discharge Register. Serum C-reactive protein (CRP) levels were measured to assess inflammation. RESULTS: An inverse association between serum DGLA concentration and incidence of depression was found after adjustment for several potential confounders (Hazard ratio HR 0.53, CI 0.36-0.79, P=0.002). The association between DGLA and depression was not dependent on inflammation (P-interaction=0.618). LIMITATIONS: Our findings may not be generalizable to individuals below middle-age or women. Moreover, we were unable to consider cases with mild depression in the longitudinal setting. CONCLUSIONS: Higher serum DGLA concentrations may predict lower risk of develop depression in elderly men. Further studies are warranted to address potential mechanisms as mechanism behind this association remains unclear.