Perceptions towards COVID-19 and adoption of preventive measures among the public in Saudi Arabia: a cross sectional study.

BACKGROUND: Effective management of the spread of a novel infectious disease, such as the COVID-19 virus can be achieved through influencing people's behavior to adopt preventive measures. The public's perceptions and attitudes towards the virus, governmental guidance and preventive measures were unknown in Saudi Arabia. OBJECTIVES: 1) investigate the public perception of COVID-19, anxiety level, the COVID-19 information sources sought, adoption of preventive measures, and ability and willingness to self-isolate during and post-lockdown periods of the COVID-19 pandemic in Saudi Arabia; 2) investigate socio-demographic factors associated with adoption of preventive measures against COVID-19 and self-isolation practices. METHOD: Between April 22nd and June 21st 2020, Saudi adults aged ≥18 years voluntarily completed a self-administered web-based cross-sectional survey, distributed through social media (WhatsApp) and emails to representatives in education, health, business, and social sectors across all Saudi Arabian regions. The survey included questions on anxiety level, COVID-19 risk perceptions and adoption of preventive measures. Weighted percentages, Pearson's chi-square tests, and multiple logistic regression were applied to evaluate associations between these factors and socio-demographic variables. RESULTS: A total of 2393 respondents completed the survey. A majority (74%) were worried about the COVID-19 outbreak and of those, 27% reported that it was likely that they would be infected with COVID-19; 16% believed it would be life-threatening or severe. However, only 11% of respondents reported high anxiety level. Adoption of hygiene practices and social distancing were lower among older (> 65 years) compared to younger (18-24 years) respondents (OR: 0.06; 95% CI: 0.01, 0.28 and OR 0.06; 95% CI: 0.01, 0.27 respectively). High percentages of respondents reported being able to (88%) and were willing to (82%) self-isolate. Those with the lowest gross household income and those with at least one flu symptom were less able and willing to self-isolate. A significant increase in levels of anxiety, perceived effectiveness of social distancing and hygiene practices was reported in the post-lockdown compared to during the lockdown. CONCLUSIONS: The study reported high levels of adoption of preventive measures, willingness and perceived ability to self-isolate during the early phase of the pandemic. Vulnerable groups such as the elderly, and those with low socio-economic status reported lower adoption of preventive measures or ability and willingness to self-isolate. Tailored public health messages and interventions are needed to achieve high adherence to these preventive measures in these groups.

The Effectiveness of Prompts to Promote Engagement With Digital Interventions: A Systematic Review.

BACKGROUND: Digital interventions have been effective in improving numerous health outcomes and health behaviors; furthermore, they are increasingly being used in different health care areas, including self-management of long-term conditions, mental health, and health promotion. The full potential of digital interventions is hindered by a lack of user engagement. There is an urgent need to develop effective strategies that can promote users' engagement with digital interventions. One potential method is the use of technology-based reminders or prompts. OBJECTIVE: To evaluate the effectiveness of technology-based strategies for promoting engagement with digital interventions. METHODS: Cochrane Collaboration guidelines on systematic review methodology were followed. The search strategy was executed across 7 electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Web of Science, the Education Resources Information Center (ERIC), PsycINFO, and the Cumulative Index to Nursing and Allied Health Literature (CINAHL). Databases were searched from inception to September 13, 2013, with no language or publication type restrictions, using three concepts: randomized controlled trials, digital interventions, and engagement. Gray literature and reference lists of included studies were also searched. Titles and abstracts were independently screened by 2 authors, then the full texts of potentially eligible papers were obtained and double-screened. Data from eligible papers were extracted by one author and checked for accuracy by another author. Bias was assessed using the Cochrane risk of bias assessment tool. Narrative synthesis was performed on all included studies and, where appropriate, data were pooled using meta-analysis. All findings were reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. RESULTS: A total of 14 studies were included in the review with 8774 participants. Of the 14 studies, 9 had sufficient data to be included in the meta-analyses. The meta-analyses suggested that technology-based strategies can potentially promote engagement compared to no strategy for dichotomous outcomes (relative risk [RR] 1.27, 95% CI 1.01-1.60, I(2)=71%), but due to considerable heterogeneity and the small sample sizes in most studies, this result should be treated with caution. No studies reported adverse or economic outcomes. Only one study with a small sample size compared different characteristics; the study found that strategies promoting new digital intervention content and those sent to users shortly after they started using the digital intervention were more likely to engage users. CONCLUSIONS: Overall, studies reported borderline positive effects of technology-based strategies on engagement compared to no strategy. However, the results have to be interpreted with caution. More research is needed to replicate findings and understand which characteristics of the strategies are effective in promoting engagement and how cost-effective they are.

Nonlinear reduction in risk for colorectal cancer by fruit and vegetable intake based on meta-analysis of prospective studies.

BACKGROUND & AIMS: The association between fruit and vegetable intake and colorectal cancer risk has been investigated by many studies but is controversial because of inconsistent results and weak observed associations. We summarized the evidence from cohort studies in categorical, linear, and nonlinear, dose-response meta-analyses. METHODS: We searched PubMed for studies of fruit and vegetable intake and colorectal cancer risk that were published until the end of May 2010. We included 19 prospective studies that reported relative risk estimates and 95% confidence intervals (CIs) of colorectal cancer-associated with fruit and vegetable intake. Random effects models were used to estimate summary relative risks. RESULTS: The summary relative risk for the highest vs the lowest intake was 0.92 (95% CI: 0.86-0.99) for fruit and vegetables combined, 0.90 (95% CI: 0.83-0.98) for fruit, and 0.91 (95% CI: 0.86-0.96) for vegetables (P for heterogeneity=.24, .05, and .54, respectively). The inverse associations appeared to be restricted to colon cancer. In linear dose-response analysis, only intake of vegetables was significantly associated with colorectal cancer risk (summary relative risk=0.98; 95% CI: 0.97-0.99), per 100 g/d. However, significant inverse associations emerged in nonlinear models for fruits (Pnonlinearity<.001) and vegetables (Pnonlinearity=.001). The greatest risk reduction was observed when intake increased from very low levels of intake. There was generally little evidence of heterogeneity in the analyses and there was no evidence of small-study bias. CONCLUSIONS: Based on meta-analysis of prospective studies, there is a weak but statistically significant nonlinear inverse association between fruit and vegetable intake and colorectal cancer risk.

Factors that influence the implementation of e-health: a systematic review of systematic reviews (an update).

BACKGROUND: There is a significant potential for e-health to deliver cost-effective, quality health care, and spending on e-health systems by governments and healthcare systems is increasing worldwide. However, there remains a tension between the use of e-health in this way and implementation. Furthermore, the large body of reviews in the e-health implementation field, often based on one particular technology, setting or health condition make it difficult to access a comprehensive and comprehensible summary of available evidence to help plan and undertake implementation. This review provides an update and re-analysis of a systematic review of the e-health implementation literature culminating in a set of accessible and usable recommendations for anyone involved or interested in the implementation of e-health. METHODS: MEDLINE, EMBASE, CINAHL, PsycINFO and The Cochrane Library were searched for studies published between 2009 and 2014. Studies were included if they were systematic reviews of the implementation of e-health. Data from included studies were synthesised using the principles of meta-ethnography, and categorisation of the data was informed by the Consolidated Framework for Implementation Research (CFIR). RESULTS: Forty-four reviews mainly from North America and Europe were included. A range of e-health technologies including electronic medical records and clinical decision support systems were represented. Healthcare settings included primary care, secondary care and home care. Factors important for implementation were identified at the levels of the following: the individual e-health technology, the outer setting, the inner setting and the individual health professionals as well as the process of implementation. CONCLUSION: This systematic review of reviews provides a synthesis of the literature that both acknowledges the multi-level complexity of e-health implementation and provides an accessible and useful guide for those planning implementation. New interpretations of a large amount of data across e-health systems and healthcare settings have been generated and synthesised into a set of useable recommendations for practice. This review provides a further empirical test of the CFIR and identifies areas where additional research is necessary. TRIAL REGISTRATION: PROSPERO, CRD42015017661.

Achieving change in primary care--causes of the evidence to practice gap: systematic reviews of reviews.

BACKGROUND: This study is to identify, summarise and synthesise literature on the causes of the evidence to practice gap for complex interventions in primary care. DESIGN: This study is a systematic review of reviews. METHODS: MEDLINE, EMBASE, CINAHL, Cochrane Library and PsychINFO were searched, from inception to December 2013. Eligible reviews addressed causes of the evidence to practice gap in primary care in developed countries. Data from included reviews were extracted and synthesised using guidelines for meta-synthesis. RESULTS: Seventy reviews fulfilled the inclusion criteria and encompassed a wide range of topics, e.g. guideline implementation, integration of new roles, technology implementation, public health and preventative medicine. None of the included papers used the term "cause" or stated an intention to investigate causes at all. A descriptive approach was often used, and the included papers expressed "causes" in terms of "barriers and facilitators" to implementation. We developed a four-level framework covering external context, organisation, professionals and intervention. External contextual factors included policies, incentivisation structures, dominant paradigms, stakeholders' buy-in, infrastructure and advances in technology. Organisation-related factors included culture, available resources, integration with existing processes, relationships, skill mix and staff involvement. At the level of individual professionals, professional role, underlying philosophy of care and competencies were important. Characteristics of the intervention that impacted on implementation included evidence of benefit, ease of use and adaptability to local circumstances. We postulate that the "fit" between the intervention and the context is critical in determining the success of implementation. CONCLUSIONS: This comprehensive review of reviews summarises current knowledge on the barriers and facilitators to implementation of diverse complex interventions in primary care. To maximise the uptake of complex interventions in primary care, health care professionals and commissioning organisations should consider the range of contextual factors, remaining aware of the dynamic nature of context. Future studies should place an emphasis on describing context and articulating the relationships between the factors identified here. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42014009410.

Exploring the challenges of implementing e-health: a protocol for an update of a systematic review of reviews.

INTRODUCTION: There is great potential for e-health to deliver cost-effective, quality healthcare and spending on e-health systems by governments and healthcare systems is increasing worldwide. However, the literature often describes problematic and unsuccessful attempts to implement these new technologies into routine clinical practice. To understand and address the challenges of implementing e-health, a systematic review was conducted in 2009, which identified several conceptual barriers and facilitators to implementation. As technology is rapidly changing and new e-health solutions are constantly evolving to meet the needs of current practice, an update of this review is deemed necessary to understand current challenges to the implementation of e-health. This research aims to identify, summarise and synthesise currently available evidence, by undertaking a systematic review of reviews to explore the barriers and facilitators to implementing e-health across a range of healthcare settings. METHODS AND ANALYSIS: This is a protocol for an update of a systematic review of reviews. We will search MEDLINE, EMBASE, CINAHL, PSYCINFO and The Cochrane Library for studies published between 2009 and 2014. We will check reference lists of included studies for further studies. Two authors will independently screen the titles and abstracts identified from the search; any discrepancies will be resolved by discussion and consensus. Full-text papers will be obtained and relevant reviews will be selected against inclusion criteria. Eligible reviews have to be based on the implementation of e-health technologies. Data from eligible reviews will be extracted using a data abstraction form. A thematic analysis of barriers and facilitators to e-health implementation will be conducted. ETHICS AND DISSEMINATION: Ethical approval is not required. The permission of the original authors to update the review was sought and granted. TRIAL REGISTRATION NUMBER: PROSPERO CRD42015017661.

The effectiveness of technology-based strategies to promote engagement with digital interventions: a systematic review protocol.

BACKGROUND: Digital interventions provide effective and potentially cost-effective models for improving health outcomes as they deliver health information and services that are widely disseminated, confidential, and can be tailored to needs of the individual user. Digital interventions have been used successfully for health promotion, mental health, and for enabling self-management of long-term conditions. However, their effectiveness is limited by low usage rates, with non-engagement a major challenge. Hence, it is crucial to find effective strategies to increase user engagement with digital interventions. OBJECTIVE: This systematic review will aim to evaluate the effectiveness of technology-based strategies to promote engagement with digital interventions. METHODS: We will follow Cochrane Collaboration guidelines on systematic review methodology. The search strategy will be executed across seven e-databases (including MEDLINE, EMBASE, PsycINFO, CINAHL) using the concepts "digital intervention" and "engagement", limited by study type (randomized controlled trial). Grey literature and reference lists of included studies will be searched. Titles and abstracts will be independently screened by 2 authors. Then the full text of potentially eligible papers will be obtained and double screened. Data from eligible papers will be extracted by 1 author and checked for accuracy by another author. Bias will be assessed using the Cochrane bias assessment tool. Narrative synthesis will report on all included studies, and where appropriate, data will be pooled using meta-analysis. All findings will be reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Sources of heterogeneity will be further investigated if required. RESULTS: Our research is in progress. The final draft of the systematic review is being written and will be submitted before the end of 2015. CONCLUSIONS: The review findings will inform researchers and digital intervention providers about optimal use of technology-based strategies to promote engagement with digital interventions. TRIAL REGISTRATION: PROSPERO International Prospective Register of Systematic Reviews: CRD42014010164; http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42014010164#.VTZmmiFViko (Archived by WebCite at http://www.webcitation.org/6XxQC8fT8).

Achieving change in primary care--effectiveness of strategies for improving implementation of complex interventions: systematic review of reviews.

OBJECTIVE: To identify, summarise and synthesise available literature on the effectiveness of implementation strategies for optimising implementation of complex interventions in primary care. DESIGN: Systematic review of reviews. DATA SOURCES: MEDLINE, EMBASE, CINAHL, Cochrane Library and PsychINFO were searched, from first publication until December 2013; the bibliographies of relevant articles were screened for additional reports. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Eligible reviews had to (1) examine effectiveness of single or multifaceted implementation strategies, (2) measure health professional practice or process outcomes and (3) include studies from predominantly primary care in developed countries. Two reviewers independently screened titles/abstracts and full-text articles of potentially eligible reviews for inclusion. DATA SYNTHESIS: Extracted data were synthesised using a narrative approach. RESULTS: 91 reviews were included. The most commonly evaluated strategies were those targeted at the level of individual professionals, rather than those targeting organisations or context. These strategies (eg, audit and feedback, educational meetings, educational outreach, reminders) on their own demonstrated a small to modest improvement (2-9%) in professional practice or behaviour with considerable variability in the observed effects. The effects of multifaceted strategies targeted at professionals were mixed and not necessarily more effective than single strategies alone. There was relatively little review evidence on implementation strategies at the levels of organisation and wider context. Evidence on cost-effectiveness was limited and data on costs of different strategies were scarce and/or of low quality. CONCLUSIONS: There is a substantial literature on implementation strategies aimed at changing professional practices or behaviour. It remains unclear which implementation strategies are more likely to be effective than others and under what conditions. Future research should focus on identifying and assessing the effectiveness of strategies targeted at the wider context and organisational levels and examining the costs and cost-effectiveness of implementation strategies. PROSPERO REGISTRATION NUMBER: CRD42014009410.

Addressing the evidence to practice gap for complex interventions in primary care: a systematic review of reviews protocol.

INTRODUCTION: Getting the results of research implemented into routine healthcare is often a challenge. The disconnect between the development and implementation of evidence into practice is called the 'second translational gap' and is particularly apparent in primary care. To address this gap, we plan to identify, summarise and synthesise currently available evidence by undertaking a systematic review of reviews to: (1) explore barriers and facilitators of implementation of research evidence or complex interventions, and (2) assess the effectiveness of strategies in facilitating implementation of complex interventions in primary care. METHODS AND ANALYSIS: This is a protocol for a systematic review of reviews. We will search MEDLINE, EMBASE, the Cochrane Library, CINAHL and PsycINFO up until December 2013. We will check reference lists of included studies for further studies. Two authors will independently screen the titles and abstracts identified from the search; any discrepancies will be resolved by discussion and consensus. Full-text papers will be obtained and relevant reviews will be selected against inclusion criteria. Eligible reviews have to be based on predominantly primary care in developed countries and examine either factors to implementation or, the effectiveness of strategies to optimise implementation. Data from eligible reviews will be extracted using standardised data abstraction forms. For barriers and facilitators, data will be synthesised using an interpretative meta-synthesis approach. For implementation strategies, findings will be summarised and described narratively and synthesised using a framework approach. All findings will be reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. ETHICS AND DISSEMINATION: Ethical approval is not required. The review findings will inform the work of the design and implementation of future studies and will be of interest to a wide audience including health professionals, researchers, health service or commissioning managers and policymakers. TRIAL REGISTRATION NUMBER: Protocol registration number (PROSPERO CRD42014009410).

Magnesium intake and colorectal tumor risk: a case-control study and meta-analysis.

BACKGROUND: Dietary magnesium might be related to colorectal tumor risk through the pivotal roles of magnesium in cellular metabolism, insulin resistance, and systemic inflammation. OBJECTIVE: We evaluated the hypothesis of whether higher dietary magnesium intake is associated with reduced colorectal tumor risk. DESIGN: A case-control study on colorectal adenomas (768 cases; 709 polyp-free control subjects) and a meta-analysis of colorectal adenomas (3 case-control studies) and carcinomas (6 prospective cohort studies) were conducted. Dietary magnesium was estimated from food-frequency questionnaires in the case-control study and most studies in the meta-analyses. Data analysis comprised multiple logistic regression analysis (case-control study) and fixed- and random-effects meta-analyses. RESULTS: The case-control study showed a nonsignificant inverse association between dietary magnesium intake and risk of colorectal adenomas (OR for every 100-mg/d increase: 0.81; 95% CI: 0.62, 1.06). However, inverse associations were observed only in subjects with BMI (in kg/m²) ≥25, in subjects aged ≥55 y, and for advanced adenomas. Associations did not vary by the calcium-to-magnesium intake ratio. In the meta-analysis, every 100-mg/d increase in magnesium intake was associated with 13% lower risk of colorectal adenomas (OR: 0.87; 95% CI: 0.75, 1.00) and 12% lower risk of colorectal cancer (RR: 0.88; 95% CI: 0.81, 0.97). CONCLUSIONS: Our findings support the hypothesis that higher intakes of dietary magnesium are associated with lower risk of colorectal tumors. The consumption of magnesium-rich foods may be a new avenue to explore further in the search for cancer-prevention strategies.

Selenium and prostate cancer: systematic review and meta-analysis.

BACKGROUND: Prostate cancer is a growing public health problem. Several human studies have shown a potentially protective effect of selenium, but the conclusions from published reports are inconsistent. OBJECTIVE: The objective was to examine the evidence for relations between selenium intake, selenium status, and prostate cancer risk. DESIGN: This was a systematic review and meta-analysis of randomized controlled trials, case-control studies, and prospective cohort studies. The World Cancer Research Fund/American Institute for Cancer Research Continuous Update Project database was searched up to September 2010. The studies included reported measurements of selenium intake or status (plasma, serum, or toenail selenium), assessments of prostate cancer cases (number of events), and the RR in the adult population. Meta-analyses were performed, and study quality, heterogeneity, and small study effects were assessed. Dose-response meta-analyses were used, with restricted cubic splines and fractional polynomials for nonlinear trends, to investigate the association between selenium status and prostate cancer risk. RESULTS: Twelve studies with a total of 13,254 participants and 5007 cases of prostate cancer were included. The relation between plasma/serum selenium and prostate cancer in a nonlinear dose-response meta-analysis showed that the risk decreased with increasing plasma/serum selenium up to 170 ng/mL. Three high-quality studies included in the meta-analysis of toenail selenium and cancer risk indicated a reduction in prostate cancer risk (estimated RR: 0.29; 95% CI: 0.14, 0.61) with a toenail selenium concentration between 0.85 and 0.94 µg/g. CONCLUSION: The relation between selenium status and decreased prostate cancer risk was examined over a relatively narrow range of selenium status; further studies in low-selenium populations are required.

Dietary fibre, whole grains, and risk of colorectal cancer: systematic review and dose-response meta-analysis of prospective studies.

OBJECTIVE: To investigate the association between intake of dietary fibre and whole grains and risk of colorectal cancer. DESIGN: Systematic review and meta-analysis of prospective observational studies. DATA SOURCES: PubMed and several other databases up to December 2010 and the reference lists of studies included in the analysis as well as those listed in published meta-analyses. STUDY SELECTION: Prospective cohort and nested case-control studies of dietary fibre or whole grain intake and incidence of colorectal cancer. RESULTS: 25 prospective studies were included in the analysis. The summary relative risk of developing colorectal cancer for 10 g daily of total dietary fibre (16 studies) was 0.90 (95% confidence interval 0.86 to 0.94, I(2) = 0%), for fruit fibre (n = 9) was 0.93 (0.82 to 1.05, I(2) = 23%), for vegetable fibre (n = 9) was 0.98 (0.91 to 1.06, I(2) = 0%), for legume fibre (n = 4) was 0.62 (0.27 to 1.42, I(2) = 58%), and for cereal fibre (n = 8) was 0.90 (0.83 to 0.97, I(2) = 0%). The summary relative risk for an increment of three servings daily of whole grains (n = 6) was 0.83 (0.78 to 0.89, I(2) = 18%). CONCLUSION: A high intake of dietary fibre, in particular cereal fibre and whole grains, was associated with a reduced risk of colorectal cancer. Further studies should report more detailed results, including those for subtypes of fibre and be stratified by other risk factors to rule out residual confounding. Further assessment of the impact of measurement errors on the risk estimates is also warranted.

Red and processed meat and colorectal cancer incidence: meta-analysis of prospective studies.

BACKGROUND: The evidence that red and processed meat influences colorectal carcinogenesis was judged convincing in the 2007 World Cancer Research Fund/American Institute of Cancer Research report. Since then, ten prospective studies have published new results. Here we update the evidence from prospective studies and explore whether there is a non-linear association of red and processed meats with colorectal cancer risk. METHODS AND FINDINGS: Relevant prospective studies were identified in PubMed until March 2011. For each study, relative risks and 95% confidence intervals (CI) were extracted and pooled with a random-effects model, weighting for the inverse of the variance, in highest versus lowest intake comparison, and dose-response meta-analyses. Red and processed meats intake was associated with increased colorectal cancer risk. The summary relative risk (RR) of colorectal cancer for the highest versus the lowest intake was 1.22 (95% CI  =  1.11-1.34) and the RR for every 100 g/day increase was 1.14 (95% CI  =  1.04-1.24). Non-linear dose-response meta-analyses revealed that colorectal cancer risk increases approximately linearly with increasing intake of red and processed meats up to approximately 140 g/day, where the curve approaches its plateau. The associations were similar for colon and rectal cancer risk. When analyzed separately, colorectal cancer risk was related to intake of fresh red meat (RR(for 100 g/day increase)  =  1.17, 95% CI  =  1.05-1.31) and processed meat (RR (for 50 g/day increase)  =  1.18, 95% CI  =  1.10-1.28). Similar results were observed for colon cancer, but for rectal cancer, no significant associations were observed. CONCLUSIONS: High intake of red and processed meat is associated with significant increased risk of colorectal, colon and rectal cancers. The overall evidence of prospective studies supports limiting red and processed meat consumption as one of the dietary recommendations for the prevention of colorectal cancer.

Meta-analyses of vitamin D intake, 25-hydroxyvitamin D status, vitamin D receptor polymorphisms, and colorectal cancer risk.

BACKGROUND: Our objective was to conduct a systematic review and meta-analysis of prospective studies on colorectal cancer (CRC) and vitamin D intake and 25-hydroxyvitamin D status, as part of the World Cancer Research Fund Continuous Update Project. We also aimed at conducting meta-analysis of all studies on CRC and vitamin D receptor (VDR) single-nucleotide polymorphisms. METHODS: Relevant studies were identified in PubMed (up to June 2010). Inclusion criteria were original and peer-reviewed publications with a prospective design (for studies on vitamin D intake or status). Random effects of dose-response meta-analyses were performed on cancer incidence. RESULTS: We observed inverse associations of CRC risk with dietary vitamin D [summary relative risk (RR) per 100 IU/day = 0.95, 95% CI: 0.93-0.98; 10 studies; range of intake (midpoints) = 39-719 IU/day] and serum/plasma 25-hydroxyvitamin D (RR per 100 IU/L = 0.96, 0.94-0.97; 6 studies; range = 200-1,800 IU/L), but not with total vitamin D (5 studies). Supplemental (2 studies; range = 0-600 IU/day) and total (4 studies; range = 79-732 IU/day) vitamin D intake and 25-hydroxyvitamin D status (6 studies; range = 200-1,800 IU/L) were inversely associated with colon cancer risk. We did not observe statistically significant associations between FokI, PolyA, TaqI, Cdx2, and ApaI VDR polymorphisms and CRC risk. The BsmI polymorphism was associated with a lower CRC risk (RR = 0.57, 0.36-0.89 for BB versus bb, 8 studies). CONCLUSIONS: These meta-analyses support the evidence of an inverse association between vitamin D intake, 25-hydroxyvitamin D status, and the BsmI VDR polymorphism and CRC risk. IMPACT: Improving vitamin D status could be potentially beneficial against CRC incidence.