Potential increased risk of cancer from commonly used medications: an umbrella review of meta-analyses

Population-based analysis of the human development index and risk factors for head and neck cancer

BACKGROUND

We aimed to investigate global variations in incidence and mortality and their associations to possible risk factors for prompt cancer prevention and control.

METHODS

Estimates of incidence and mortality rates for six types of head and neck cancer were extracted from the GLOBOCAN 2020 database. Summary exposure values for level-two risk factors were obtained from the Global Burden of Disease. Regression models adjusting for the human development index (HDI) were constructed to analyze correlations between age-standardized rates and risk factors.

RESULTS

The incidence rates of multiple types of head and neck cancer were positively associated with HDI tiers. In addition to tobacco use and alcohol consumption, high systolic blood pressure was associated with the incidence and mortality of cancers of the salivary glands, oropharynx, hypopharynx, and larynx. Dietary risks were linked to cancers of the oropharynx, nasopharynx, and hypopharynx.

CONCLUSIONS

This comprehensive analysis provides valuable insights into possible risk factors for head and neck cancer.

Clinical utility of overviews on adverse events of pharmacological interventions

BACKGROUND

Overviews (i.e., systematic reviews of systematic reviews, meta-reviews, umbrella reviews) are a relatively new type of evidence synthesis. Among others, one reason to conduct an overview is to investigate adverse events (AEs) associated with a healthcare intervention. Overviews aim to provide easily accessible information for healthcare decision-makers including clinicians. We aimed to evaluate the clinical utility of overviews investigating AEs.

METHODS

We used a sample of 27 overviews exclusively investigating drug-related adverse events published until 2021 identified in a prior project. We defined clinical utility as the extent to which overviews are perceived to be useful in clinical practice. Each included overview was assigned to one of seven pharmacological experts with expertise on the topic of the overview. The clinical utility and value of these overviews were determined using a self-developed assessment tool. This included four open-ended questions and a ranking of three clinical utility statements completed by clinicians. We calculated frequencies for the ranked clinical utility statements and coded the answers to the open-ended questions using an inductive approach.

RESULTS

The overall agreement with the provided statements was high. According to the assessments, 67% of the included overviews generated new knowledge. In 93% of the assessments, the overviews were found to add value to the existing literature. The overviews were rated as more useful than the individual included systematic reviews (SRs) in 85% of the assessments. The answers to the open-ended questions revealed two key aspects of clinical utility in the included overviews. Firstly, it was considered useful that they provide a summary of available evidence (e.g., along with additional assessments, or across different populations, or in different settings that have not been evaluated together in the included SRs). Secondly, it was found useful if overviews conducted a new meta-analysis to answer specific research questions that had not been answered previously.

CONCLUSIONS

Overviews on drug-related AEs are considered valuable for clinical practice by clinicians. They can make available evidence on AEs more accessible and provide a comprehensive view of available evidence. As the role of overviews evolves, investigations such as this can identify areas of value.

A review found heterogeneous approaches and insufficient reporting in overviews on adverse events

OBJECTIVES

To investigate reporting and methodological characteristics of overviews on adverse (drug-associated) events (AEs) of pharmacological interventions.

STUDY DESIGN AND SETTING

We searched MEDLINE, Embase, Epistemonikos, and the Cochrane Database of Systematic Reviews from inception to May 17, 2021 for overviews exclusively investigating AEs of pharmacological interventions. We extracted general, reporting, and methodological characteristics and analyzed data descriptively.

RESULTS

We included 27 overviews, 70% of which were published in 2016 or later. The most common nomenclature in the title was "overview" (56%), followed by "umbrella review" (26%). The median number of included systematic reviews (SRs) in each overview was 15 (interquartile range 7-34). Study selection methods were reported in 52%, methods for data extraction in 67%, and methods for critical appraisal in 63% of overviews. An assessment of methodological quality of included SRs was performed in 70% of overviews. Only 22% of overviews reported strategies for dealing with overlapping SRs. An assessment of the certainty of the evidence was performed in 33% of overviews.

CONCLUSION

To ensure methodological rigor, authors of overviews on AEs should follow available guidance for the conduct and reporting of overviews.

Risk of Dementia in Cancer Survivors: A Meta-Analysis of Population-Based Cohort Studies

Background: A negative association between cancer and Alzheimer’s disease (AD) was revealed. Objective: We aimed to further explore the dementia risk among cancer survivors and then among cancer survivors who received cancer treatment in subsequent subgroup analyses. Methods: Databases of PubMed, Embase, and Cochrane Library were systematically searched from inception to April 1, 2021, following PRISMA and MOOSE guidelines. Relative risks (RR) of dementia were pooled by a random-effects model stratifying the data by potential confounding factors to explore the heterogeneity. This study is registered with PROSPERO, number CRD42021250654. Results: A total of 36 studies were included in this meta-analysis, of which 16 studies were about the risk of dementia in cancer survivors, and 20 studies were about the risk of dementia in survivors who accepted cancer treatment. The pooled RR reached 0.89 ([95% CI = 0.82–0.97], I2 = 97.9%) for dementia and 0.89 ([0.83–0.95], I2 = 92.6%) for AD in cancer survivors compared with non-cancer controls. Notably, both dementia risk and AD risk significantly decreased in survivors of colon, leukemia, small intestine, and thyroid cancers (RR ranged from 0.64 to 0.92). Furthermore, prostate cancer patients treated with androgen deprivation therapy exhibited a significantly increased risk of dementia (RR:1.18 [1.09–1.27], I2 = 89.5%) and AD (RR:1.17 [1.08–1.25], I2 = 81.3%), with evidence of between-study heterogeneity. Conclusion: Currently, available evidence suggests that the risk of dementia among cancer survivors is decreased. However, large-scale prospective cohort studies are warranted to further prove the association.

Metabolic obesity phenotypes: a friend or foe of digestive polyps?-An observational study based on National Inpatient Database

OBJECTIVE

Obesity is associated with an increased risk of digestive polyps, whereas all obesity are not created equally. The role of metabolic states in occurrence risks of polyps among individuals with varying degrees of obesity remains unknown. Our study aimed to evaluate the association between metabolic obesity phenotypes and the occurrence of digestive polyps.

RESEARCH DESIGN AND METHODS

Data from 9,278,949 patients between 2016 and 2018 from the National Inpatient Sample (NIS) database, a nationally representative database of all discharges from US health-care hospitals, were analyzed. According to obesity phenotype, the study population was classified into four groups: metabolically healthy nonobese (MHNO), metabolically unhealthy nonobese (MUNO), metabolically healthy obese (MHO) and metabolically unhealthy obese (MUO). We calculated the incidence rates of various digestive polyps (stomach/duodenum, colon and rectum polyps) among these participants by searching the hospital records for ICD-10 diagnosis codes indicating each gastric, duodenum, colon or rectal polyps. The multiple stepwise regression analysis and further in-depth subgroup analysis were used to determine the associations between metabolic obesity phenotypes and the occurrence of digestive polyps.

RESULTS

In the total or female population, those with the MUNO and MUO phenotypes had significantly higher prevalence of digestive polyps compared with individuals with the MHNO or MHO phenotypes (all p < 0.05) and a significant difference was not found between MUNO and MUO phenotypes (p > 0.05). Obese subjects seem to be more likely to develop stomach and duodenum polyps or colon polyps than non-obese subjects in metabolically healthy people of males (MHO vs. MHNO, p < 0.05), whereas obesity status seems to have little effect on the occurrence of digestive polyps in metabolically healthy people of females (MHO vs. MHNO, p>0.05). After adjusting for the potential confounders, the MHO, MUNO and MUO phenotypes were all risk factors for stomach and duodenum polyps (OR = 1.46, 95% CI: 1.36-1.58, p< 0.01; OR = 1.19, 95% CI: 1.14-1.25, p< 0.01; OR = 1.44, 95% CI: 1.35-1.55, p< 0.01, respectively) or colon polyps (OR = 1.28, 95% CI: 1.21-1.35, p< 0.01; OR = 1.18, 95% CI: 1.14-1.22, p< 0.01; OR = 1.46, 95% CI: 1.38-1.54, p< 0.01, respectively) compared with the MHNO phenotype，especially in menopausal female. Interestingly, we also observed in further in-depth subgroup analysis that metabolic abnormalities may have a greater impact on the occurrence of digestive polyps than obesity (all p < 0.05).

CONCLUSIONS

Both metabolic abnormities and obesity were associated with a higher risk of digestive polyps. The effect of metabolism on digestive polyp occurrence may be stronger than that of obesity, highlighting the importance of abnormal metabolic status modification regardless of obesity status. Clinical intervention should not only focus on obesity, but also on metabolic abnormalities to decrease digestive polyp risk.

Design and methodological characteristics of studies using observational routinely collected health data for investigating the link between cancer and neurodegenerative diseases: protocol for a meta-research study

INTRODUCTION

Health services generate large amounts of routine health data (eg, administrative databases, disease registries and electronic health records), which have important secondary uses for research. Increases in the availability and the ability to access and analyse large amounts of data represent a major opportunity for conducting studies on the possible relationships between complex diseases. The objective of this study will be to evaluate the design, methods and reporting of studies conducted using observational routinely collected health data for investigating the link between cancer and neurodegenerative diseases.

METHODS AND ANALYSIS

This is the protocol for a meta-research study. We registered the study protocol within the Open Science Framework: https://osf.io/h2qjg. We will evaluate observational studies (eg, cohort and case-control) conducted using routinely collected health data for investigating the associations between cancer and neurodegenerative diseases (such as Alzheimer's disease, amyotrophic lateral sclerosis/motor neuron disease, Huntington's disease, multiple sclerosis and Parkinson's disease). The following electronic databases will be searched (from their inception onwards): MEDLINE, Embase and Web of Science Core Collection. Screening and selection of articles will be conducted by at least two researchers. Potential discrepancies will be resolved via discussion. Design, methods and reporting characteristics in each article will be extracted using a standardised data extraction form. Information on general, methodological and transparency items will be reported. We will summarise our findings with tables and graphs (eg, bar charts, forest plots).

ETHICS AND DISSEMINATION

Due to the nature of the proposed study, no ethical approval will be required. We plan to publish the full study in an open access peer-reviewed journal and disseminate the findings at scientific conferences and via social media. All data will be deposited in a cross-disciplinary public repository.

Effects of Antihypertensive Drugs Use on Risk and Prognosis of Colorectal Cancer: A Meta-Analysis of 37 Observational Studies

Background: Antihypertensive drugs might play a key role in the risk and poor prognosis of colorectal cancer. However, current epidemiologic evidence remains inconsistent. The aim of this study is to quantify the association between antihypertensive drugs and colorectal cancer. Methods: To identify available studies, we systematically searched electronic databases: PubMed, Web of Science, Embase, Cochrane Library. The risk estimates and their corresponding 95% confidence intervals (CIs) were collected and analyzed by using random-effects models. Heterogeneity test and sensitivity analysis were also performed. Results: Overall, 37 observational studies were included in this analysis (26 studies with cohort design, three studies with nested case-control design, and 8 studies with case-control design). Antihypertensive drugs did not present a significant effect on the risk or overall survival of patients with colorectal cancer [Risk ratio (RR) = 1.00, 95% CI: 0.95-1.04; Hazard ratio (HR) = 0.93, 95% CI: 0.84-1.02]. In the subgroup analysis, diuretics use was significantly associated with a worse overall survival of patients with colorectal cancer (HR = 1.27; 95% CI: 1.14-1.40). However, use of angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers was associated with improved progression-free survival of patients who suffered from colorectal cancer (HR = 0.83; 95% CI: 0.72-0.95). Conclusion: Antihypertensive drug usage did not influence the risk and overall survival of patients with colorectal cancer in general. Further investigation reminded us that diuretics use might reduce the overall survival time in colorectal cancer patients, whereas those who took Angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers had a longer progression-free survival.

Drug-Wide Association Study (DWAS): Challenges and Opportunities

Cancer risk associations with commonly prescribed medications have been mainly evaluated in hypothesis-driven studies that focus on one drug at a time. Agnostic drug-wide association studies (DWAS) offer an alternative approach to simultaneously evaluate associations between a large number of drugs with one or more cancers using large-scale electronic health records. Although cancer DWAS approaches are promising, a number of challenges limit their applicability. This includes the high likelihood of false positivity; lack of biological considerations; and methodological shortcomings, such as inability to tightly control for confounders. As such, the value of DWAS is currently restricted to hypothesis generation with detected signals needing further evaluation. In this commentary, we discuss those challenges in more detail and summarize the approaches to overcome them by using published cancer DWAS studies, including the accompanied article by Støer and colleagues. Despite current concerns, DWAS future is filled with opportunities for developing innovative analytic methods and techniques that incorporate pharmacology, epidemiology, cancer biology, and genetics.See related article by Støer et al., p. 682.

Disease-modifying agents for multiple sclerosis and the risk for reporting cancer: A disproportionality analysis using the US Food and Drug Administration Adverse Event Reporting System database

AIM

While the efficacy of disease-modifying therapies (DMTs) for patients with multiple sclerosis (MS) is established, little is known about their long-term safety. Cancer-risk after DMT use remains unclear. This study aimed to investigate whether the prescription of DMTs for patients with MS increases the risk of reporting cancer.

METHODS

Data from the Food and Drug Administration Adverse Event Reporting System were extracted from 2004 to 2020. After data cleaning, the crude and adjusted reported odds ratios (cROR and aROR) for cancer were calculated for DMTs with Interferon beta-1a as the reference drug. Sensitivity analyses investigated the group of reports with multiple registered DMTs, the effect of indication restriction and the results when using the rest of the DMTs as reference.

RESULTS

For malignant tumours, aROR (95% confidence interval [CI]) values were Cladribine 0.46 (0.18-0.95), Dimethyl fumarate 0.30 (0.27-0.34), Fingolimod 0.61 (0.53-0.70), Glatiramer 0.50 (0.43-0.58), Alemtuzumab 0.84 (0.64-1.08), Interferon beta-1b 0.49 (0.42-0.56), Natalizumab 0.36 (0.34-0.39), Ocrelizumab 0.48 (0.29-0.74), Peginterferon beta-1a 0.35 (0.26-0.48), Siponimod 0.89 (0.47-1.54) and Teriflunomide 0.25(0.21-0.30) adjusted to age, gender and concomitant medications. In the sensitivity analysis, when the rest of the drugs were used as a reference, Interferon beta-1a and Peginterferon beta-1a had aROR (95% CI) 2.60 (2.47-2.74, P < .001) and Alemtuzumab had aROR 1.47 (1.13-1.88, I = .003).

CONCLUSIONS

No safety signal for increased cancer risk was detected among the approved DMTs. A potential safety signal detected in the sensitivity analysis concerning Interferon beta-1a and Alemtuzumab requires further evaluation with more robust evidence.

Development of a Web-Based System for Exploring Cancer Risk With Long-term Use of Drugs: Logistic Regression Approach

Background

Existing epidemiological evidence regarding the association between the long-term use of drugs and cancer risk remains controversial.

Objective

We aimed to have a comprehensive view of the cancer risk of the long-term use of drugs.

Methods

A nationwide population-based, nested, case-control study was conducted within the National Health Insurance Research Database sample cohort of 1999 to 2013 in Taiwan. We identified cases in adults aged 20 years and older who were receiving treatment for at least two months before the index date. We randomly selected control patients from the patients without a cancer diagnosis during the 15 years (1999-2013) of the study period. Case and control patients were matched 1:4 based on age, sex, and visit date. Conditional logistic regression was used to estimate the association between drug exposure and cancer risk by adjusting potential confounders such as drugs and comorbidities.

Results

There were 79,245 cancer cases and 316,980 matched controls included in this study. Of the 45,368 associations, there were 2419, 1302, 662, and 366 associations found statistically significant at a level of P<.05, P<.01, P<.001, and P<.0001, respectively. Benzodiazepine derivatives were associated with an increased risk of brain cancer (adjusted odds ratio [AOR] 1.379, 95% CI 1.138-1.670; P=.001). Statins were associated with a reduced risk of liver cancer (AOR 0.470, 95% CI 0.426-0.517; P<.0001) and gastric cancer (AOR 0.781, 95% CI 0.678-0.900; P<.001). Our web-based system, which collected comprehensive data of associations, contained 2 domains: (1) the drug and cancer association page and (2) the overview page.

Conclusions

Our web-based system provides an overview of comprehensive quantified data of drug-cancer associations. With all the quantified data visualized, the system is expected to facilitate further research on cancer risk and prevention, potentially serving as a stepping-stone to consulting and exploring associations between the long-term use of drugs and cancer risk.

Systematic review and meta-analysis of randomised controlled clinical trial evidence refutes relationship between pharmacotherapy with angiotensin-receptor blockers and an increased risk of cancer

AIMS

The potential influence of angiotensin-receptor blockers (ARBs) on carcinogenesis is a much-debated topic. Both observational, as well as preclinical studies in rodent carcinogenic assays, suggest a major role of the Renin-Angiotensin-Aldosterone-System (RAAS) in cancer development. Therefore, a systematic review and meta-analysis with available study data on ARBs and carcinogenicity in general as primary outcome were conducted. Secondary outcomes were defined as tumour-specific mortality rates and the frequency of new cases of specific tumour types with particular emphasis on lung, breast, and prostate cancer.

METHODS

A systematic literature research was performed in MEDLINE, EMBASE, Cochrane Library, and TOXLINE. We used a combination of MeSH terms, keywords and substance names of ARBs and searched between 1950 and 2016. At least 100 participants in each study arm and a minimum follow-up for one year were necessary for study inclusion. Odds ratios (OR) were calculated by a random-effects model.

RESULTS

A total of 8818 potentially eligible publications were identified of whom seven randomised controlled trials, four case-control studies and one cohort study met our inclusion criteria. As a key result, we found no effect on carcinogenesis in randomised controlled trials for ARB usage. (OR 1.02, 95% CI 0.87-1.19; p = .803). Conflicting results with observational studies could be explained by poor reporting- and study qualities.

CONCLUSIONS

The results of our meta-analysis focusing only on high evidence levels and study designs (RCTs) did not reveal any relationship between pharmacotherapy with an ARB and an increased risk for cancer in general.

Cancer incidence among Finnish people with type 2 diabetes during 1989-2014

Diabetes and cancer are common diseases both with enormous impact on health burden globally. The increased risk of several types of cancer among people with type 2 diabetes mellitus has been indicated repeatedly. This study aimed at exploring and describing the association between type 2 diabetes and cancer incidence. A cohort of 428,326 people with type 2 diabetes was identified from the Finnish National Diabetes Register and followed up through a register linkage with the Finnish Cancer Registry for cancer incidence during 1988-2014. A total of 74,063 cases of cancer occurred in this cohort in 4.48 million person-years. This accounted for 16% more than the expected cancer incidence in the Finnish general population; the standardized incidence ratio (SIR) was 1.16 (95% confidence interval [CI] 1.15-1.16). There was a statistically significant excess of cancers of lip (SIR = 1.40, CI = 1.28-1.53), liver (SIR = 2.44, CI = 2.35-2.53), pancreas (SIR = 1.75, CI = 1.70-1.79), stomach (SIR = 1.22, CI = 1.18-1.26), colon (SIR = 1.22, CI = 1.19-1.25), gallbladder and bile ducts (SIR = 1.29, CI = 1.21-1.36), non-melanoma skin (SIR = 1.18, CI = 1.15-1.22), kidney (SIR = 1.42, CI = 1.37-1.47), bladder (SIR = 1.17, CI = 1.13-1.21), and thyroid (SIR = 1.22, CI = 1.12-1.31). There was a small statistically significant decrease in prostate cancer incidence (SIR = 0.95, CI = 0.93-0.96). This study showed an association between type 2 diabetes mellitus and the incidence of cancer at numerous sites in the Finnish population.

What causes psychosis? An umbrella review of risk and protective factors

Psychosis is a heterogeneous psychiatric condition for which a multitude of risk and protective factors have been suggested. This umbrella review aimed to classify the strength of evidence for the associations between each factor and psychotic disorders whilst controlling for several biases. The Web of Knowledge database was searched to identify systematic reviews and meta-analyses of observational studies which examined associations between socio-demographic, parental, perinatal, later factors or antecedents and psychotic disorders, and which included a comparison group of healthy controls, published from 1965 to January 31, 2017. The literature search and data extraction followed PRISMA and MOOSE guidelines. The association between each factor and ICD or DSM diagnoses of non-organic psychotic disorders was graded into convincing, highly suggestive, suggestive, weak, or non-significant according to a standardized classification based on: number of psychotic cases, random-effects p value, largest study 95% confidence interval, heterogeneity between studies, 95% prediction interval, small study effect, and excess significance bias. In order to assess evidence for temporality of association, we also conducted sensitivity analyses restricted to data from prospective studies. Fifty-five meta-analyses or systematic reviews were included in the umbrella review, corresponding to 683 individual studies and 170 putative risk or protective factors for psychotic disorders. Only the ultra-high-risk state for psychosis (odds ratio, OR=9.32, 95% CI: 4.91-17.72) and Black-Caribbean ethnicity in England (OR=4.87, 95% CI: 3.96-6.00) showed convincing evidence of association. Six factors were highly suggestive (ethnic minority in low ethnic density area, second generation immigrants, trait anhedonia, premorbid IQ, minor physical anomalies, and olfactory identification ability), and nine were suggestive (urbanicity, ethnic minority in high ethnic density area, first generation immigrants, North-African immigrants in Europe, winter/spring season of birth in Northern hemisphere, childhood social withdrawal, childhood trauma, Toxoplasma gondii IgG, and non-right handedness). When only prospective studies were considered, the evidence was convincing for ultra-high-risk state and suggestive for urbanicity only. In summary, this umbrella review found several factors to be associated with psychotic disorders with different levels of evidence. These risk or protective factors represent a starting point for further etiopathological research and for the improvement of the prediction of psychosis.

Physical activity and cancer: an umbrella review of the literature including 22 major anatomical sites and 770 000 cancer cases

OBJECTIVE

To provide an overview of the breadth and validity of claimed associations between physical activity and risk of developing or dying from cancer.

DESIGN

Umbrella review.

DATA SOURCES

We searched Medline, Embase, Cochrane Database and Web of Science.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Systematic reviews about physical activity and cancer incidence and cancer mortality in different body sites among general population.

RESULTS

We included 19 reviews covering 22 cancer sites, 26 exposure-outcome pairs meta-analyses and 541 original studies. Physical activity was associated with lower risk of seven cancer sites (colon, breast, endometrial, lung, oesophageal, pancreas and meningioma). Only colon (a protective association with recreational physical activity) and breast cancer (a protective association with overall physical activity) were supported by strong evidence and highly suggestive evidence, respectively. Evidence from endometrial, lung, oesophageal, pancreas and meningioma presented hints of uncertainty and bias in the literature (eg, not reaching P values<10^-6) showing large between-study heterogeneity and/or not demonstrating a definite direction for the effect when 95% prediction intervals were considered. Four of the 26 meta-analyses showed small study effects and 4 showed excess significance.

CONCLUSION

Physical activity is associated with a lower risk of several cancers, but only colon and breast cancer associations were supported by strong or highly suggestive evidence, respectively. Evidence from other cancer sites was less consistent, presenting hints of uncertainty and/or bias.

Obesity and gynaecological and obstetric conditions: umbrella review of the literature

Objective To study the strength and validity of associations between adiposity and risk of any type of obstetric or gynaecological conditions.Design An umbrella review of meta-analyses.Data sources PubMed, Cochrane database of systematic reviews, manual screening of references for systematic reviews or meta-analyses of observational and interventional studies evaluating the association between adiposity and risk of any obstetrical or gynaecological outcome.Main outcomes Meta-analyses of cohort studies on associations between indices of adiposity and obstetric and gynaecological outcomes.Data synthesis Evidence from observational studies was graded into strong, highly suggestive, suggestive, or weak based on the significance of the random effects summary estimate and the largest study in the included meta-analysis, the number of cases, heterogeneity between studies, 95% prediction intervals, small study effects, excess significance bias, and sensitivity analysis with credibility ceilings. Interventional meta-analyses were assessed separately.Results 156 meta-analyses of observational studies were included, investigating associations between adiposity and risk of 84 obstetric or gynaecological outcomes. Of the 144 meta-analyses that included cohort studies, only 11 (8%) had strong evidence for eight outcomes: adiposity was associated with a higher risk of endometrial cancer, ovarian cancer, antenatal depression, total and emergency caesarean section, pre-eclampsia, fetal macrosomia, and low Apgar score. The summary effect estimates ranged from 1.21 (95% confidence interval 1.13 to 1.29) for an association between a 0.1 unit increase in waist to hip ratio and risk endometrial cancer up to 4.14 (3.61 to 4.75) for risk of pre-eclampsia for BMI >35 compared with <25. Only three out of these eight outcomes were also assessed in meta-analyses of trials evaluating weight loss interventions. These interventions significantly reduced the risk of caesarean section and pre-eclampsia, whereas there was no evidence of association with fetal macrosomia.Conclusions Although the associations between adiposity and obstetric and gynaecological outcomes have been extensively studied, only a minority were considered strong and without hints of bias.

Cancer and central nervous system disorders: protocol for an umbrella review of systematic reviews and updated meta-analyses of observational studies

BACKGROUND

The objective of this study will be to synthesize the epidemiological evidence and evaluate the validity of the associations between central nervous system disorders and the risk of developing or dying from cancer.

METHODS/DESIGN

We will perform an umbrella review of systematic reviews and conduct updated meta-analyses of observational studies (cohort and case-control) investigating the association between central nervous system disorders and the risk of developing or dying from any cancer or specific types of cancer. Searches involving PubMed/MEDLINE, EMBASE, SCOPUS and Web of Science will be used to identify systematic reviews and meta-analyses of observational studies. In addition, online databases will be checked for observational studies published outside the time frames of previous reviews. Eligible central nervous system disorders will be Alzheimer's disease, anorexia nervosa, amyotrophic lateral sclerosis, autism spectrum disorders, bipolar disorder, depression, Down's syndrome, epilepsy, Huntington's disease, multiple sclerosis, Parkinson's disease and schizophrenia. The primary outcomes will be cancer incidence and cancer mortality in association with a central nervous system disorder. Secondary outcome measures will be site-specific cancer incidence and mortality, respectively. Two reviewers will independently screen references identified by the literature search, as well as potentially relevant full-text articles. Data will be abstracted, and study quality/risk of bias will be appraised by two reviewers independently. Conflicts at all levels of screening and abstraction will be resolved through discussion. Random-effects meta-analyses of primary observational studies will be conducted where appropriate. Parameters for exploring statistical heterogeneity are pre-specified. The World Cancer Research Fund (WCRF)/American Institute for Cancer Research (AICR) criteria and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach will be used for determining the quality of evidence for cancer outcomes.

DISCUSSION

Our study will establish the extent of the epidemiological evidence underlying the associations between central nervous system disorders and cancer and will provide a rigorous and updated synthesis of a range of important site-specific cancer outcomes.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016052762.

Trends in published meta-analyses in cancer research, 2008-2013

In order to capture trends in the contribution of epidemiology to cancer research, we describe an online meta-analysis database resource for cancer clinical and population research and illustrate trends and descriptive detail of cancer meta-analyses from 2008 through 2013. A total of 4,686 cancer meta-analyses met our inclusion criteria. During this 6-year period, a fivefold increase was observed in the yearly number of meta-analyses. Fifty-six percent of meta-analyses concerned observational studies, mostly of cancer risk, more than half of which were genetic studies. The major cancer sites were breast, colorectal, and digestive. This online database for Cancer Genomics and Epidemiology Navigator will be continuously updated to allow investigators to quickly navigate the meta-analyses emerging from cancer epidemiology studies and cancer clinical trials.

Diet, body size, physical activity and risk of prostate cancer: An umbrella review of the evidence

The existing literature on the relationship between diet, body size, physical activity and prostate cancer risk was summarised by the World Cancer Research Fund Continuous Update Project (CUP). An evaluation of the robustness of this evidence is required to help inform public health policy. The robustness of this evidence was evaluated using several criteria addressing evidence strength and validity, including the statistical significance of the random effects summary estimate and of the largest study in a meta-analysis, number of prostate cancer cases, between-study heterogeneity, 95% prediction intervals, small-study effects bias, excess significance bias and sensitivity analyses with credibility ceilings. A total of 248 meta-analyses were extracted from the CUP, which studied associations of 23 foods, 31 nutrients, eight indices of body size and three indices of physical activity with risk of total prostate cancer development, mortality or cancer development by stage and grade. Of the 176 meta-analyses using a continuous scale to measure the exposures, no association presented strong evidence by satisfying all the aforementioned criteria. Only the association of height with total prostate cancer incidence and mortality presented highly suggestive evidence with a 4% higher risk per 5 cm greater height (95% confidence interval, 1.03, 1.05). Associations for body mass index, weight, height, dietary calcium and spirits intake were supported by suggestive evidence. Overall, the association of diet, body size, physical activity and prostate cancer has been extensively studied, but no association was graded with strong evidence.

Use of existing systematic reviews for evidence assessments in infectious disease prevention: a comparative case study

BACKGROUND

Given limited resources and time constraints, the use of existing systematic reviews (SR) for the development of evidence-based public health recommendations has become increasingly important. Recently, a five-step approach for identifying, analyzing, appraising and using existing SRs based on recent guidance by the US Agency for Healthcare Research and Quality (AHRQ) was proposed within the Project on a Framework for Rating Evidence in Public Health (PRECEPT). However, case studies are needed to test whether this approach is useful, what challenges arise and how problems can be solved.

METHODS

In two case studies, the five-step approach was applied to integrate existing SRs in the development of evidence-based public health recommendations. Case study A focused on the role of neonatal sepsis as a risk factor for adverse neurodevelopmental outcome. Case study B examined the efficacy, effectiveness and safety of influenza vaccination during pregnancy. For each step, we report the approach of the review team, discuss challenges and describe solutions.

RESULTS

For case study A, one existing SR was identified, while in case study B four SRs were eligible for analysis. We found that comparison of inclusion criteria alone was sufficient to judge on relevance of SRs in case study A, but not B. Although methodological quality of all identified SRs was acceptable, risk of bias assessments of individual studies included in the SRs had to be repeated in both case studies. Particular challenges appeared in case study B where multiple SRs addressed the same research question. With the help of spreadsheets comparing the characteristics of the existing SR we decided to use the most comprehensive one for our evidence synthesis and supplemented the results with those from the other SRs.

CONCLUSIONS

In both case studies using the complete SR was not possible. The five-step approach provided useful and structured guidance and should be routinely applied when using existing SRs as a basis for evidence-based recommendations in public health. In situations where more than one SR has to be considered, the development of spreadsheets comparing characteristics, inclusion criteria, risk of bias, included studies and outcomes seems useful.

Systematic assessment of pharmaceutical prescriptions in association with cancer risk: a method to conduct a population-wide medication-wide longitudinal study

It is a public health priority to identify the adverse and non-adverse associations between pharmaceutical medications and cancer. We search for and evaluate associations between all prescribed medications and longitudinal cancer risk in participants of the Swedish Cancer Register (N = 9,014,975). We associated 552 different medications with incident cancer risk (any, breast, colon, and prostate) during 5.5 years of follow-up (7/1/2005-12/31/2010) in two types of statistical models, time-to-event and case-crossover. After multiple hypotheses correction and replication, 141 (26%) drugs were associated with any cancer in a time-to-event analysis constraining drug exposure to 1 year before first cancer diagnosis and adjusting for history of medication use. In a case-crossover analysis, 36 drugs (7%) were associated with decreased cancer risk. 12 drugs were found in common in both analyses with concordant direction of association. We found 14, 10, 7% of all drugs associated with colon, prostate, and breast cancers in time-to-event models. We only found 1, 2%, and 0% for these cancers, respectively, in case-crossover analyses. Pharmacoepidemiologic analyses of cancer risk are sensitive to modeling choices and false-positive findings are a threat. Medication-wide analyses using different analytical models may help suggest consistent signals of increased cancer risk.

Neurological sequelae of healthcare-associated sepsis in very-low-birthweight infants: Umbrella review and evidence-based outcome tree

Sepsis is a frequent cause of death in very-low-birthweight infants and often results in neurological impairment. Its attributable risk of sequelae has not been systematically assessed. To establish an outcome tree for mapping the burden of neonatal sepsis, we performed systematic literature searches to identify systematic reviews addressing sequelae of neonatal sepsis. We included cohort studies and performed meta-analyses of attributable risks. Evidence quality was assessed using GRADE. Two systematic reviews met inclusion criteria. The first included nine cohort studies with 5,620 participants and five outcomes (neurodevelopmental impairment, cerebral palsy, vision impairment, hearing impairment, death). Pooled risk differences varied between 4% (95% confidence interval (CI):2-10) and 13% (95% CI:5-20). From the second review we analysed four studies with 472 infants. Positive predictive value of neurodevelopmental impairment for later cognitive impairment ranged between 67% (95% CI:22-96) and 83% (95% CI:36-100). Neonatal sepsis increases risk of permanent neurological impairment. Effect size varies by outcome, with evidence quality being low to very low. Data were used to construct an outcome tree for neonatal sepsis. Attributable risk estimates for sequelae following neonatal sepsis are suitable for burden estimation and may serve as outcome parameters in interventional studies.

Hypertension, use of antihypertensive medications, and risk of epithelial ovarian cancer

Few studies have examined the associations of hypertension and antihypertensive medications with ovarian cancer. In particular, beta-blockers, one of the most commonly prescribed medications to treat hypertension, may reduce ovarian cancer risk by inhibiting beta-adrenergic signaling. We prospectively followed 90,384 women in the Nurses' Health Study (NHS) between 1988-2012 and 113,121 NHSII participants between 1989-2011. Hypertension and use of antihypertensive medications were self-reported biennially. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). We documented 948 ovarian cancer cases during follow-up. Similar results were observed in the two cohorts. While hypertension was not associated with ovarian cancer risk (Pooled HR = 1.01; 95% CI = 0.88, 1.16), current use of any antihypertensive medication was associated with slightly increased risk compared to never users (Pooled HR = 1.18; 95% CI: 1.02, 1.37). This increased risk was primarily due to use of thiazide diuretics (Pooled HR = 1.37; 95% CI: 1.13, 1.68). No associations were observed for beta-blockers or angiotensin-converting-enzyme inhibitors. Calcium channel blockers (CCBs) were associated with suggestively reduced risk (NHS HR = 0.73; 95% CI: 0.53, 1.01), after adjusting for all antihypertensive medications. Associations were similar among hypertensive women and stronger for longer use of thiazide diuretics and CCBs. In conclusion, our results provided no evidence that beta-blockers were associated with reduced ovarian cancer risk. In contrast, we observed an increased risk for use of thiazide diuretics that should be confirmed in other studies.

Association between colorectal polyps and hypertension treatment

OBJECTIVE

Patients who take drugs regularly are increasing, not least due to metabolic and orthopedic diseases. In the present study we aimed to investigate the association between the use of drugs, such as non-steroidal anti-inflammatory drugs (NSAIDs) and low-dose aspirin, and colorectal polyps diagnosed based on colonoscopic findings.

METHODS

In total, 1318 consecutive patients who underwent total colonoscopy for the first time were cross-sectionally analyzed. Personal data including comorbidities and all medications were obtained by a questionnaire. Their blood pressure, body weight and waist circumference were measured just before the colonoscopic examination.

RESULTS

Colorectal polyps were found in 577 (43.8%) patients, with a prevalence of 57.6% (296/514) in patients receiving antihypertensive treatment and 35.0% (281/804) in patients not undergoing such treatment. A multivariate analysis showed that age, waist circumference, alcohol consumption, smoking and the use of antihypertensive drugs were independent risk factors for colorectal polyps. In a secondary multivariate analysis incorporating the parameters of measured blood pressure and medication status, the number of antihypertensive drugs was strongly associated with the risk of colorectal polyps, whereas blood pressure showed no significant association.

CONCLUSIONS

The use of antihypertensive drug may be a risk factor for colorectal polyps. Furthermore, this risk increases with the intensive use of antihypertensive drugs.

Incidence of Cancer in ANCA-Associated Vasculitis: A Meta-Analysis of Observational Studies

Objective

The purpose of this paper is to examine cancer incidence in patients with ANCA-associated vasculitis (AASV) derived from population-based cohort studies by means of meta-analysis.

Methods

Relevant electronic databases were searched for studies characterizing the associated risk of overall malignancy in patients with AASV. Standardized incidence rates (SIRs) with 95% confidence intervals (CIs) were used to evaluate the strength of association. We tested for publication bias and heterogeneity and stratified for site-specific cancers.

Results

Six studies (n = 2,578) were eventually identified, of which six provided the SIR for overall malignancy, five reported the SIR for non-melanoma skin cancer (NMSC), four for leukemia, five for bladder cancer, three for lymphoma, three for liver cancer, four for lung cancer, three for kidney cancer, four for prostate cancer, four for colon cancer and four for breast cancer. Overall, the pooled SIR of cancer in AASV patients was 1.74 (95%CI = 1.37–2.21), with moderate heterogeneity among these studies (I² = 65.8%, P = 0.012). In sub-analyses for site-specific cancers, NMSC, leukemia and bladder cancer were more frequently observed in patients with AASV with SIR of 5.18 (95%CI = 3.47–7.73), 4.89 (95%CI = 2.93–8.16) and 3.84 (95%CI = 2.72–5.42) respectively. There was no significant increase in the risk of kidney cancer (SIR = 2.12, 95%CI = 0.66–6.85), prostate cancer (SIR = 1.45, 95%CI = 0.87–2.42), colon cancer (SIR = 1.26, 95%CI = 0.70–2.27), and breast cancer (SIR = 0.95, 95%CI = 0.50–1.79). Among these site-specific cancers, only NMSC showed moderate heterogeneity (I² = 55.8%, P = 0.06). No publication bias was found by using the Begg’s test and Egger's test.

Conclusions

This meta-analysis shows that AASV patients treatment with cyclophosphamide (CYC) are at increased risk of late-occurring malignancies, particularly of the NMSC, leukemia and bladder cancer. However, there is no significant association between AASV and kidney cancer, prostate cancer, colon cancer and breast cancer. These findings emphasize monitoring and preventative management in AASV patients after cessation of CYC therapy is momentous.