Vitamin D-tour : cognition and depression: the role of vitamin D and its interplay with glucose homeostasis

According to recent estimations approximately 35.6 million people have dementia worldwide. Globally, 350 million people experience one or more depressive episodes during their life. As the therapeutic options for dementia and depression are limited, these conditions form a major challenge for public health and society. More and more researchers have initiated research on potential preventive factors for dementia and depression, including the potential effects of nutritional factors. The aim of this PhD-thesis was to study the role of vitamin D and its potential interplay with glucose homeostasis, in the development of cognitive decline and depression, using epidemiological data as well experimental animal data. Chapter 2 recapitulates a debate between vitamin D experts that was organized to make a step towards the harmonization on the formulation of optimal vitamin D intake levels and serum 25(OH)D concentrations across Europe. It was concluded that based on the current evidence-base 25(OH)D concentrations ≥50 nmol/L are sufficient with respect to optimal bone health. For health outcomes beyond bone health evidence was considered insufficient to formulate optimal levels. In order to achieve and maintain a 25(OH)D concentration ≥50 nmol/L, older adults aged ≥65 years were recommended to adhere to a vitamin D intake of 20 μg/day. Chapter 3 shows that there is a high prevalence of 25(OH)D inadequacy in a population of Dutch older adults that participated in the B-PROOF study (n=2857), namely 45% had 25(OH)D concentrations In chapter 4 the associations between 25(OH)D status and global cognitive performance (n=116), depressive symptoms (n=118), and surrogate markers of glucose intolerance (n=593) were evaluated using data of European adults aged 70-75 years. None of the associations reached significance. Studying the potential role of vitamin D in domain-specific cognitive performance and depression in 127 Dutch pre-frail and frail older adults aged ≥65 years (chapter 5), showed an association between 25(OH)D concentration and executive functioning, and a tendency towards an association with information processing speed. Stratification for ‘low’ and ‘high’ fasting glucose concentrations did not suggest an interaction between vitamin D and glucose homeostasis in the association with domain-specific cognitive performance. Moreover, adding fasting glucose or insulin did not substantially influence the associations between 25(OH)D status and domain-specific cognitive performance, and hence a mediation effect of glucose homeostasis was considered unlikely. We furthermore observed associations of 25(OH)D status with attention and working memory (n=787) (chapter 6), depression (n=2839) (chapter 7) and grey matter volume of the brain (n=217) (chapter 8) in a population community-dwelling Dutch older adults aged ≥65 years. Again, these studies did not provide evidence that the associations were modified or mediated by glucose intolerance. However, it should be emphasized that glucose intolerance in these three chapters was defined sub-optimally, specifically using blood samples that may have been collected in a non-fasting state, or by using self-reported diabetes data. Hence, the mediation and interaction effects should be interpreted cautiously. Finally, chapter 9 shows the results of a proof of principle study on the effect of a long-term vitamin D deficiency on cognitive decline and emotional reactivity in old C57BL/6j mice. Modest tendencies were shown for a relation between vitamin D and spatial learning, but these tendencies did not reach significance. Vitamin D deficiency did not affect recognition memory, spatial memory or emotional reactivity. Mice that received a higher dietary fat load, which was given to induce an impaired glucose tolerance, did not respond differently to a vitamin D deficiency than mice that received a low fat diet did. Overall, it is concluded that the evidence for an effect of vitamin D on cognitive performance/decline, depression or brain volume is insufficient to formulate disease specific cut-off values for vitamin D intake or 25(OH)D status. However, given the high prevalence of 25(OH)D concentrations <50 nmol/L we do call for a more active promotion of the current vitamin D intake recommendations.</p

Risk Factors of Streptococcus suis Infection in Vietnam. A Case-Control Study

Background: Streptococcus suis infection, an emerging zoonosis, is an increasing public health problem across South East Asia and the most common cause of acute bacterial meningitis in adults in Vietnam. Little is known of the risk factors underlying the disease. Methods and Findings: A case-control study with appropriate hospital and matched community controls for each patient was conducted between May 2006 and June 2009. Potential risk factors were assessed using a standardized questionnaire and investigation of throat and rectal S. suis carriage in cases, controls and their pigs, using real-time PCR and culture of swab samples. We recruited 101 cases of S. suis meningitis, 303 hospital controls and 300 community controls. By multivariate analysis, risk factors identified for S. suis infection as compared to either control group included eating "high risk" dishes, including such dishes as undercooked pig blood and pig intestine (OR1 = 2.22; 95% CI = [1.15-4.28] and OR2 = 4.44; 95% CI = [2.15-9.15]), occupations related to pigs (OR1 = 3.84; 95% CI = [1.32-11.11] and OR2 = 5.52; 95% CI = [1.49-20.39]), and exposures to pigs or pork in the presence of skin injuries (OR1 = 7.48; 95% CI = [1.97-28.44] and OR2 = 15.96; 95% CI = [2.97-85.72]). S. suis specific DNA was detected in rectal and throat swabs of 6 patients and was cultured from 2 rectal samples, but was not detected in such samples of 1522 healthy individuals or patients without S. suis infection. Conclusions: This case control study, the largest prospective epidemiological assessment of this disease, has identified the most important risk factors associated with S. suis bacterial meningitis to be eating 'high risk' dishes popular in parts of Asia, occupational exposure to pigs and pig products, and preparation of pork in the presence of skin lesions. These risk factors can be addressed in public health campaigns aimed at preventing S. suis infectio

Validation of a Dutch Risk Score Predicting Poor Outcome in Adults with Bacterial Meningitis in Vietnam and Malawi

We have previously developed and validated a prognostic model to predict the risk for unfavorable outcome in Dutch adults with bacterial meningitis. The aim of the current study was to validate this model in adults with bacterial meningitis from two developing countries, Vietnam and Malawi. Demographic and clinical characteristics of Vietnamese (n = 426), Malawian patients (n = 465) differed substantially from those of Dutch patients (n = 696). The Dutch model underestimated the risk of poor outcome in both Malawi and Vietnam. The discrimination of the original model (c-statistic [c] 0.84; 95% confidence interval 0.81 to 0.86) fell considerably when re-estimated in the Vietnam cohort (c = 0.70) or in the Malawian cohort (c = 0.68). Our validation study shows that new prognostic models have to be developed for these countries in a sufficiently large series of unselected patients

Can gold be used as a hedge against the risks of Sharia-compliant securities? Application for Islamic portfolio management

In this paper, we investigate whether gold hedges Sharia-compliant stocks and Sukuk during the period from September 2005 to October 2017. The inference is taken by using both the DCC-GARCH model and the wavelet coherence analysis. On the whole, our finding suggests that gold is not effective in hedging the fluctuations of Sharia-compliant securities. However, we find that combining gold with stocks (and Sukuk) is useful in diversification and portfolio optimization. These results imply that, while gold is an excellent hedge for plain vanilla securities, it is not for Islamic exposures. This is important in light of the increasing amount of assets that are managed according to Islamic screening

Health services for reproductive tract infections among female migrant workers in industrial zones in Ha Noi, Viet Nam: an in-depth assessment

BACKGROUND: Rural-to-urban migration involves a high proportion of females because job opportunities for female migrants have increased in urban industrial areas. Those who migrate may be healthier than those staying in the village and they may benefit from better health care services at destination, but the 'healthy' effect can be reversed at destination due to migration-related health risk factors. The study aimed to explore the need for health care services for reproductive tract infections (RTIs) among female migrants working in the Sai Dong industrial zone as well as their services utilization. METHODS: The cross sectional study employed a mixed method approach. A cohort of 300 female migrants was interviewed to collect quantitative data. Two focus groups and 20 in-depth interviews were conducted to collect qualitative data. We have used frequency and cross-tabulation techniques to analyze the quantitative data and the qualitative data was used to triangulate and to provide more in-depth information. RESULTS: The needs for health care services for RTI were high as 25% of participants had RTI syndromes. Only 21.6% of female migrants having RTI syndromes ever seek helps for health care services. Barriers preventing migrants to access services were traditional values, long working hours, lack of information, and high cost of services. Employers had limited interests in reproductive health of female migrants, and there was ineffective collaboration between the local health system and enterprises. These barriers were partly caused by lack of health promotion programs suitable for migrants. Most respondents needed more information on RTIs and preferred to receive these from their employers since they commonly work shifts--and spend most of their day time at work. CONCLUSION: While RTIs are a common health problem among female migrant workers in industrial zones, female migrants had many obstacles in accessing RTI care services. The findings from this study will help to design intervention models for RTI among this vulnerable group such as communication for behavioural impact of RTI health care, fostered collaboration between local health care services and employer enterprises, and on-site service (e.g. local or enterprise health clinics) strengthenin

A Retrospective Analysis of the Haemodynamic and Metabolic Effects of Fluid Resuscitation in Vietnamese Adults with Severe Falciparum Malaria

BACKGROUND: Optimising the fluid resuscitation of patients with severe malaria is a simple and potentially cost-effective intervention. Current WHO guidelines recommend central venous pressure (CVP) guided, crystalloid based, resuscitation in adults. METHODS: Prospectively collected haemodynamic data from intervention trials in Vietnamese adults with severe malaria were analysed retrospectively to assess the responses to fluid resuscitation. RESULTS: 43 patients were studied of whom 24 received a fluid load. The fluid load resulted in an increase in cardiac index (mean increase: 0.75 L/min/m(2) (95% Confidence interval (CI): 0.41 to 1.1)), but no significant change in acid-base status post resuscitation (mean increase base deficit 0.6 mmol/L (95% CI: -0.1 to 1.3). The CVP and PAoP (pulmonary artery occlusion pressure) were highly inter-correlated (r(s) = 0.7, p<0.0001), but neither were correlated with acid-base status (arterial pH, serum bicarbonate, base deficit) or respiratory status (PaO(2)/FiO(2) ratio). There was no correlation between the oxygen delivery (DO(2)) and base deficit at the 63 time-points where they were assessed simultaneously (r(s) = -0.09, p = 0.46). CONCLUSIONS: In adults with severe falciparum malaria there was no observed improvement in patient outcomes or acid-base status with fluid loading. Neither CVP nor PAoP correlated with markers of end-organ perfusion or respiratory status, suggesting these measures are poor predictors of their fluid resuscitation needs

Search for the standard model Higgs boson decaying to a bbˉb\bar{b} pair in events with no charged leptons and large missing transverse energy using the full CDF data set

We report on a search for the standard model Higgs boson produced in association with a vector boson in the full data set of proton-antiproton collisions at $\sqrt{s} = 1.96$ TeV recorded by the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.45 fb$^{-1}$. We consider events having no identified charged lepton, a transverse energy imbalance, and two or three jets, of which at least one is consistent with originating from the decay of a $b$ quark. We place 95% credibility level upper limits on the production cross section times standard model branching fraction for several mass hypotheses between 90 and $150 \mathrm{GeV}/c^2$. For a Higgs boson mass of $125 \mathrm{GeV}/c^2$, the observed (expected) limit is 6.7 (3.6) times the standard model prediction.Comment: Accepted by Phys. Rev. Let

Search for the standard model Higgs boson decaying to a bb pair in events with one charged lepton and large missing transverse energy using the full CDF data set

We present a search for the standard model Higgs boson produced in association with a W boson in sqrt(s) = 1.96 TeV p-pbar collision data collected with the CDF II detector at the Tevatron corresponding to an integrated luminosity of 9.45 fb-1. In events consistent with the decay of the Higgs boson to a bottom-quark pair and the W boson to an electron or muon and a neutrino, we set 95% credibility level upper limits on the WH production cross section times the H->bb branching ratio as a function of Higgs boson mass. At a Higgs boson mass of 125 GeV/c2 we observe (expect) a limit of 4.9 (2.8) times the standard model value.Comment: Submitted to Phys. Rev. Lett (v2 contains clarifications suggested by PRL

Search for the standard model Higgs boson decaying to a bb pair in events with two oppositely-charged leptons using the full CDF data set

We present a search for the standard model Higgs boson produced in association with a Z boson in data collected with the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.45/fb. In events consistent with the decay of the Higgs boson to a bottom-quark pair and the Z boson to electron or muon pairs, we set 95% credibility level upper limits on the ZH production cross section times the H -> bb branching ratio as a function of Higgs boson mass. At a Higgs boson mass of 125 GeV/c^2 we observe (expect) a limit of 7.1 (3.9) times the standard model value.Comment: To be submitted to Phys. Rev. Let