Wichor Bramer
University of Groningen, Biology, Alumnus
Research Interests:
The antioxidant lutein is suggested as being beneficial to cardiometabolic health because of its protective effect against oxidative stress, but evidence has not systematically been evaluated. We aimed to evaluate systematically the... more
The antioxidant lutein is suggested as being beneficial to cardiometabolic health because of its protective effect against oxidative stress, but evidence has not systematically been evaluated. We aimed to evaluate systematically the effects of lutein (intake or concentrations) on cardiometabolic outcomes in different life stages. This is a systematic review with meta-analysis of literature published in MEDLINE, Embase, Cochrane Central, Web of Science, PubMed, and Google Scholar up to August 2014. Included were trials and cohort, case-control, and cross-sectional studies in which the association between lutein concentrations, dietary intake, or supplements and cardiometabolic outcomes was reported. Two independent investigators reviewed the articles. Seventy-one relevant articles were identified that included a total of 387,569 participants. Only 1 article investigated the effects of lutein during pregnancy, and 3 studied lutein in children. Furthermore, 31 longitudinal, 33 cross-se...
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Abnormal gestational weight gain is associated with unfavorable pregnancy outcomes. Several risk factors have been identified, but the effect of macronutrient intake during pregnancy on gestational weight gain has not been systematically... more
Abnormal gestational weight gain is associated with unfavorable pregnancy outcomes. Several risk factors have been identified, but the effect of macronutrient intake during pregnancy on gestational weight gain has not been systematically evaluated in both high-income countries and low- and middle-income countries. We conducted a systematic review of the literature in 8 different databases (until 12 August 2015) to assess whether energy intake and macronutrient intake (i.e., protein, fat, and carbohydrate) during pregnancy were associated with gestational weight gain (following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines). Of 7623 identified references, we included 56 articles (46 observational studies and 10 trials, 28 of which were in high-income countries and 28 of which were in low- and middle-income countries). Eleven of the included articles were of high quality (20%). Results of 5 intervention and 7 high-quality observational studies suggested...
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Searching for systematic reviews can be quite challenging. But even when you are not searching for a systematic review it can take lots of time before you can be sure that you did not miss important articles. We have developed a method... more
Searching for systematic reviews can be quite challenging. But even when you are not searching for a systematic review it can take lots of time before you can be sure that you did not miss important articles. We have developed a method that allows for faster creation of search strategies but with good quality.
Chronic neck pain is a common problem with a poorly understood pathophysiology. Often no underlying structural pathology can be found and radiological imaging findings are more related to age than to a patient's symptoms. Besides its... more
Chronic neck pain is a common problem with a poorly understood pathophysiology. Often no underlying structural pathology can be found and radiological imaging findings are more related to age than to a patient's symptoms. Besides its common occurrence, chronic idiopathic neck pain is also very disabling with almost 50% of all neck pain patients showing moderate disability at long-term follow-up. Central sensitization (CS) is defined as "an amplification of neural signaling within the central nervous system that elicits pain hypersensitivity," "increased responsiveness of nociceptive neurons in the central nervous system to their normal or subthreshold afferent input," or "an augmentation of responsiveness of central neurons to input from unimodal and polymodal receptors." There is increasing evidence for involvement of CS in many chronic pain conditions. Within the area of chronic idiopathic neck pain, there is consistent evidence for the presence a...
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Physicians and researchers in the field of family medicine often need to find relevant articles in online medical databases for a variety of reasons. Because a search filter may help improve the efficiency and quality of such searches, we... more
Physicians and researchers in the field of family medicine often need to find relevant articles in online medical databases for a variety of reasons. Because a search filter may help improve the efficiency and quality of such searches, we aimed to develop and validate search filters to identify research studies of relevance to family medicine. Using a new and objective method for search filter development, we developed and validated 2 search filters for family medicine. The sensitive filter had a sensitivity of 96.8% and a specificity of 74.9%. The specific filter had a specificity of 97.4% and a sensitivity of 90.3%. Our new filters should aid literature searches in the family medicine field. The sensitive filter may help researchers conducting systematic reviews, whereas the specific filter may help family physicians find answers to clinical questions at the point of care when time is limited.
Research Interests:
Research Interests:
Research Interests:
Several studies have reported that metformin can reduce the risk of hepatocellular carcinoma (HCC) in diabetes patients. However, the direct anti-HCC effects of metformin have hardly been studied in patients, but have been extensively... more
Several studies have reported that metformin can reduce the risk of hepatocellular carcinoma (HCC) in diabetes patients. However, the direct anti-HCC effects of metformin have hardly been studied in patients, but have been extensively investigated in animal models of HCC. We therefore performed a systematic review and meta-analysis of animal studies evaluating the effects of metformin on HCC. We collected the relevant studies by searching EMBASE, Medline (OvidSP), Web of Science, Scopus, PubMed Publisher, and Google Scholar. Studies were included according to the following inclusion criteria: HCC, animal study, and metformin intervention. Study quality was assessed using SYRCLE's risk of bias tool. A meta-analysis was performed for the outcome measures: tumor growth (tumor volume, weight and size), tumor number and incidence. The search resulted in 573 references, of which 13 could be included in the review and 12 included in the meta-analysis. The study characteristics of the i...
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Gastrointestinal endoscopy plays a crucial role in the diagnosis and management of gastrointestinal disorders. When endoscopy is indicated during pregnancy, concerns about the effects on pregnancy outcome often arise. The aim of this... more
Gastrointestinal endoscopy plays a crucial role in the diagnosis and management of gastrointestinal disorders. When endoscopy is indicated during pregnancy, concerns about the effects on pregnancy outcome often arise. The aim of this study was to assess whether lower gastrointestinal endoscopies (LGEs) across all three trimesters of pregnancy affects pregnancy outcomes. A systematic literature search was performed using Embase (including MEDLINE), Medline OvidSP, Cochrane Central Register of Controlled Trials, Web-of-Science, Google scholar and Pubmed. All original research articles from 1990 until May 2014 involving pregnant women who underwent LGE for any indication were included. Adverse pregnancy events like spontaneous abortion, preterm birth and fetal demise were assessed for a temporal and etiological relation with the LGE. In total, 5514 references were screened by two independent reviewers. Eighty-two references met the inclusion criteria and were selected. Two retrospectiv...
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Non-communicable diseases (NCDs) have large economic impact at multiple levels. To systematically review the literature investigating the economic impact of NCDs [including coronary heart disease (CHD), stroke, type 2 diabetes mellitus... more
Non-communicable diseases (NCDs) have large economic impact at multiple levels. To systematically review the literature investigating the economic impact of NCDs [including coronary heart disease (CHD), stroke, type 2 diabetes mellitus (DM), cancer (lung, colon, cervical and breast), chronic obstructive pulmonary disease (COPD) and chronic kidney disease (CKD)] on macro-economic productivity. Systematic search, up to November 6th 2014, of medical databases (Medline, Embase and Google Scholar) without language restrictions. To identify additional publications, we searched the reference lists of retrieved studies and contacted authors in the field. Randomized controlled trials, cohort, case-control, cross-sectional, ecological studies and modelling studies carried out in adults (>18 years old) were included. Two independent reviewers performed all abstract and full text selection. Disagreements were resolved through consensus or consulting a third reviewer. Two independent reviewer...
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Mesenchymal stem cells (MSC) are widely studied for their immunomodulatory properties. Data from in vitro and pre-clinical models demonstrate that MSC suppress activated immune cells and ameliorate the severity of experimental immune... more
Mesenchymal stem cells (MSC) are widely studied for their immunomodulatory properties. Data from in vitro and pre-clinical models demonstrate that MSC suppress activated immune cells and ameliorate the severity of experimental immune disease. In complex human studies, the immunomodulatory efficacy of MSC therapy is not well established. We conducted a systematic review of clinical studies which used MSC with the purpose of immunomodulation and included at least 10 patients to investigate the efficacy of MSC therapy. Sixty-two studies comprising 10 different immune disorders were included in the analysis, of which 18 studies represented controlled trials. Although several of the studies reported an amelioration of disease severity, other studies failed to observe a beneficial effect of MSC. The low number of randomized controlled trials, small number of studies per disease category and limited immunological readout parameters made it difficult to draw a definitive conclusion on the e...
Research Interests:
Research Interests:
Research Interests:
High protein intake in early childhood is associated with obesity, suggesting possible adverse effects on other cardiometabolic outcomes. However, studies in adults have suggested beneficial effects of protein intake on blood pressure... more
High protein intake in early childhood is associated with obesity, suggesting possible adverse effects on other cardiometabolic outcomes. However, studies in adults have suggested beneficial effects of protein intake on blood pressure (BP) and lipid profile. Whether dietary protein intake is associated with cardiovascular and metabolic health in children is unclear. Therefore, we aimed to systematically review the evidence on the associations of protein intake with BP, insulin sensitivity and blood lipids in children. We searched the databases Medline, Embase, Cochrane Central and PubMed for interventional and observational studies in healthy children up to the age of 18 years, in which associations of total, animal and/or vegetable protein intake with one or more of the following outcomes were reported: BP; measures of insulin sensitivity; cholesterol levels; or TAG levels. In the search, we identified 6636 abstracts, of which fifty-six studies met all selection criteria. In genera...
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The importance of polyunsaturated fatty acid (PUFA) intake in fetal life and infancy has been widely studied in relation to child cognitive and visual development, but whether early life PUFA exposure is related to cardiometabolic risk... more
The importance of polyunsaturated fatty acid (PUFA) intake in fetal life and infancy has been widely studied in relation to child cognitive and visual development, but whether early life PUFA exposure is related to cardiometabolic risk factors is unclear. The focus of this systematic review was to evaluate the effects of PUFA dietary intake and blood levels during pregnancy, lactation, or early childhood (⩽5y) on obesity, blood pressure, blood lipids, and insulin sensitivity. We identified 4302 abstracts in the databases Embase, Medline and Cochrane Central (April 2014), of which 56 articles, reporting on 45 unique studies, met all selection criteria. Many of the included studies focused on obesity as an outcome (33 studies), whereas studies on insulin sensitivity were relatively scarce (6 studies). Overall, results for obesity, blood pressure, and blood lipids were inconsistent, with a few studies reporting effects in opposite directions and other studies that did not observe any effects of PUFAs on these outcomes. Four studies suggested beneficial effects of PUFAs on insulin sensitivity. We conclude that there is insufficient evidence to support a beneficial effect of PUFAs in fetal life or early childhood on obesity, blood pressure, or blood lipids. More research is needed to investigate the potential favorable effects of PUFAs on insulin sensitivity, and to examine the role of specific fatty acids in early life on later cardiometabolic health.