Systematic Review Of Epidemiological Evidence Research Articles

Social and ecological determinants of antimicrobial resistance in Africa: a systematic review of epidemiological evidence.

Antimicrobial resistance (AMR) is one of the greatest global health problems for humans, animals, and the environment. Although the association between various factors and AMR is being increasingly researched, the need to understand the contribution of social and ecological determinants, especially in developing nations, remains. This review fills these knowledge gaps by synthesizing existing evidence on the social and ecological determinants of AMR in Africa. Twenty-four studies were selected based on predefined criteria from PubMed. 58.33% (n = 14) and 29.17% (n = 7) of the studies reported on ecological and social determinants of AMR, respectively, and 3 (12.5%) studies documented both social and environmental determinants of AMR. Sociodemographic factors include increased household size, poor knowledge, attitudes toward AMR, low educational levels, and rural residences. Indicators of poor water sanitation and hygiene, framing practices, and consumption of farm products were among the common ecological determinants of AMR and AM misuse in Africa. Our review demonstrates the importance of social and ecological determinants of AMR among African populations. The findings may be valuable to researchers, policymakers, clinicians, and those working in lower-income countries to implement AMR prevention programs utilizing a holistic approach.

The Gut Microbiome and Residential Surrounding Greenness: a Systematic Review of Epidemiological Evidence.

A healthy indigenous intestinal microbiome is essential for human health. Well-established gut microbiome determinants only explain 16% of the inter-individual variation in gut microbiome composition. Recent studies have focused on green space as a potential determinant of the intestinal microbiome. We systematically summarize all evidence concerning the association between green space and intestinal bacterial diversity, evenness, and richness indices, specific bacterial taxa, and potential underlying mechanisms. Seven epidemiological studies were included in this review. The majority of the included studies (n = 4) reported a positive association between green space and intestinal bacterial diversity, evenness, and richness, while two reported the opposite. There was little overlap between the publications regarding the association between green space and the relative abundance of specific bacterial taxa. Only a decrease in the relative abundance of Bacteroidetes, Bacteroides, and Anaerostipes and an increase in Lachnospiraceae and Ruminococcaceae were reported in multiple studies, predominantly suggesting that green space is positively associated with the intestinal microbiome composition, and subsequently with human health. Lastly, the only examined mechanism was a reduction in perceived psychosocial stress. Mechanisms indicated in blue and white represent tested or hypothesized mechanisms, respectively. The graphical abstract was created with illustrations from BioRender, Noun Project, and Pngtree.

Using internet-based query and climate data to predict climate-sensitive infectious disease risks: a systematic review of epidemiological evidence.

The use of internet-based query data offers a novel approach to improve disease surveillance and provides timely disease information. This paper systematically reviewed the literature on infectious disease predictions using internet-based query data and climate factors, discussed the current research progress and challenges, and provided some recommendations for future studies. We searched the relevant articles in the PubMed, Scopus, and Web of Science databases between January 2000 and December 2019. We initially included studies that used internet-based query data to predict infectious disease epidemics, then we further filtered and appraised the studies that used both internet-based query data and climate factors. In total, 129 relevant papers were included in the review. The results showed that most studies used a simple descriptive approach (n=80; 62%) to detect epidemics of influenza (including influenza-like illness (ILI)) (n=88; 68%) and dengue (n=9; 7%). Most studies (n=61; 47%) purely used internet search metrics to predict the epidemics of infectious diseases, while only 3 out of the 129 papers included both climate variables and internet-based query data. Our research shows that including internet-based query data and climate variables could better predict climate-sensitive infectious disease epidemics; however, this method has not been widely used to date. Moreover, previous studies did not sufficiently consider the spatiotemporal uncertainty of infectious diseases. Our review suggests that further research should use both internet-based query and climate data to develop predictive models for climate-sensitive infectious diseases based on spatiotemporal models.

The Effect of Alcohol on Telomere Length: A Systematic Review of Epidemiological Evidence and a Pilot Study during Pregnancy.

Several studies—albeit with still inconclusive and limited findings—began to focus on the effect of drinking alcohol on telomere length (TL). Here, we present results from a systematic review of these epidemiological studies to investigate the potential association between alcohol consumption, alcohol-related disorders, and TL. The analysis of fourteen studies—selected from PubMed, Medline, and Web of Science databases—showed that people with alcohol-related disorders exhibited shorter TL, but also that alcohol consumption per se did not appear to affect TL in the absence of alcohol abuse or dependence. Our work also revealed a lack of studies in the periconceptional period, raising the need for evaluating this potential relationship during pregnancy. To fill this gap, we conducted a pilot study using data and samples form the Mamma & Bambino cohort. We compared five non-smoking but drinking women with ten non-smoking and non-drinking women, matched for maternal age, gestational age at recruitment, pregestational body mass index, and fetal sex. Interestingly, we detected a significant difference when analyzing relative TL of leukocyte DNA of cord blood samples from newborns. In particular, newborns from drinking women exhibited shorter relative TL than those born from non-drinking women (p = 0.024). Although these findings appeared promising, further research should be encouraged to test any dose–response relationship, to adjust for the effect of other exposures, and to understand the molecular mechanisms involved.

Trace elements exposure and risk in age-related eye diseases: a systematic review of epidemiological evidence

This systematic review aimed to evaluate existing evidence on the associations between trace elements exposure and age-related eye diseases. PubMed and Google scholar databases were searched for epidemiological and postmortem studies on the relationship between exposure to trace elements and Age-related eye diseases such as age-related macular degeneration (AMD), cataract, glaucoma and diabetic retinopathy (DR), in population groups aged 40 years and above. Available evidence suggests that cadmium (Cd) exposure may be positively associated with the risks of AMD and cataract. There is also evidence that exposure to lead (Pb) may be positively associated with higher risk of cataract and glaucoma. There is limited number of relevant studies and lack of prospective studies for most of the investigated associations. Evidence for other trace elements is weak and inconsistent, and the number of available studies is small. Likewise, there are very few relevant studies on the role of trace elements in DR. Chemical elements that affect the distribution and absorption of other trace elements have never been investigated. The suggestive but limited evidence motivates large and quality prospective studies to fully characterize the impact of exposure to trace (toxic and essential) elements on age-related eye diseases.

Short-Term Tea Consumption Is Not Associated with a Reduction in Blood Lipids or Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

A recent systematic review of epidemiological evidence suggests that higher amounts of tea intake are associated with lower risks of cardiovascular disease (CVD) incidence and mortality. Our study objective was to assess mechanisms by which tea consumption may influence CVD risks. A systematic review and meta-analysis was conducted to investigate the effects of green and/or black tea consumption (≥4 wk) on systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol, LDL cholesterol, HDL cholesterol, and triglyceride (TG) in healthy populations and among at-risk adults (analyzed separately) with metabolic syndrome, prediabetes, and hypercholesterolemia. The Grading of Recommendations Assessment, Development and Evaluation approach was used to rate the strength of evidence (SoE). A total of 14 unique RCTs which randomly assigned 798 participants to either green tea, black tea, or placebo controls were included in our analyses. Intervention durations ranged from 4 to 24 wk (mean: 7.4 wk). Individual studies were judged as moderate to high quality based on risk of bias assessments. SoE was low to moderate owing to low sample sizes and insufficient power for most included studies to observe changes in the measured CVD biomarkers. Meta-analyses showed no significant effects of tea consumption on SBP, DBP, total cholesterol, LDL cholesterol, HDL cholesterol, and TG in healthy and at-risk adults (i.e., adults with obesity, prediabetes, borderline hypercholesterolemia, and metabolic syndrome). Short-term (4-24 wk) tea consumption does not appear to significantly affect blood pressure or lipids in healthy or at-risk adults, although the evidence is limited by insufficient power to detect changes in these CVD biomarkers. High-quality RCTs with longer durations and sufficient sample sizes are needed to fully elucidate the effects of tea. This systematic review was registered at www.crd.york.ac.uk/prospero/ as CRD42020134513.

Coffee, green tea and liver cancer risk: an evaluation based on a systematic review of epidemiologic evidence among the Japanese population.

Coffee and green tea, two popular drinks in the Japanese, have recently drawn much attention as potential protective factors against the occurrence of liver cancer. We systematically reviewed epidemiologic studies on coffee, green tea and liver cancer among Japanese populations. Original data were obtained by searching the MEDLINE (PubMed) and Ichushi databases, complemented with manual searches. The evaluation was performed in terms of the magnitude of association in each study and the strength of evidence ('convincing', 'probable', 'possible', or 'insufficient'), together with biological plausibility. We identified four cohort and four case-control studies on coffee and liver cancer and six cohort and one case-control studies on green tea and liver cancer. All cohort and case-control studies on coffee reported a weak to strong inverse association, with a summary relative risk (RR) for one cup increase being 0.72 (95% confidence interval [CI] 0.66-0.79). Conversely, all studies but two cohort studies on green tea reported no association, with a corresponding summary RR of 0.99 (95% CI 0.97-1.01, P = 0.37). Coffee drinking 'probably' decreases the risk of primary liver cancer among the Japanese population whereas the evidence on an association between green tea and liver cancer is 'insufficient' in this population.

Impacts of exposure to ambient temperature on burden of disease: a systematic review of epidemiological evidence.

Ambient temperature is an important determinant of mortality and morbidity, making it necessary to assess temperature-related burden of disease (BD) for the planning of public health policies and adaptive responses. To systematically review existing epidemiological evidence on temperature-related BD, we searched three databases (PubMed, Web of Science, and Scopus) on 1 September 2018. We identified 97 studies from 56 counties for this review, of which 75 reported the fraction or number of health outcomes (include deaths and diseases) attributable to temperature, and 22 reported disability-adjusted life years (include years of life lost and years lost due to disability) related to temperature. Non-optimum temperatures (i.e., heat and cold) were responsible for > 2.5% of mortality in all included high-income countries/regions, and > 3.0% of mortality in all included middle-income countries. Cold was mostly reported to be the primary source of mortality burden from non-optimum temperatures, but the relative role of three different temperature exposures (i.e., heat, cold, and temperature variability) in affecting morbidity and mortality remains unclear so far. Under the warming climate scenario, almost all projections assuming no population adaptation suggested future increase in heat-related but decrease in cold-related BD. However, some studies emphasized the great uncertainty in future pattern of temperature-related BD, largely depending on the scenarios of climate, population adaptation, and demography. We also identified important discrepancies and limitations in current research methodologies employed to measure temperature exposures and model temperature-health relationship, and calculate the past and project future temperature-related BD. Overall, exposure to non-optimum ambient temperatures has become and will continue to be a considerable contributor to the global and national BD, but future research is still needed to develop a stronger methodological framework for assessing and comparing temperature-related BD across different settings.

Cigarette smoking and cervical cancer risk: an evaluation based on a systematic review and meta-analysis among Japanese women.

There is a body of evidence to suggest that cigarette smoking increases the risk of cervical cancer in women, but no study has examined the magnitude of the association in Japanese women. Here, we evaluated the association between cigarette smoking and the risk of cervical cancer in Japanese women based on a systematic review of epidemiological evidence. Original data were obtained from a MEDLINE search using PubMed or from a search of the 'Ichushi' database, as well as by a manual search. Evaluation of associations was based on the strength of evidence and the magnitude of association, together with biological plausibility as evaluated previously by the International Agency for Research on Cancer. Meta-analysis of associations was also conducted to obtain a summarized overview of the data. We identified two cohort studies and three case-control studies. All five studies had indicated strong positive associations between cigarette smoking and the risk of cervical cancer. Our summary estimate indicated that the relative risk (RR) for individuals who had ever-smoked relative to never-smokers was 2.03 (95% confidence interval: 1.49-2.57). Four studies had also demonstrated dose-response relationships between cigarette smoking and the risk of cervical cancer. We conclude that there is convincing evidence that cigarette smoking increases the risk of cervical cancer among Japanese women.

Developing Criteria for Evaluating the Quality of Exposure Measurements in Epidemiological Studies during Systematic Review

During a systematic review of epidemiological evidence on health risk from exposure to environmental chemicals, it may be necessary to develop criteria for evaluating the quality of exposure measurements that account for specific factors relevant to the chemical of interest. We describe approaches for developing chemical-specific criteria through three case studies for exposure to phthalates, methylmercury, and hexavalent chromium.Each case study began with a set of prompting questions aimed at answering the core question: Does the exposure measure reliably distinguish between levels of exposure in a time window considered most relevant for a causal effect with respect to the outcome? We then developed additional follow-up questions specific to each chemical (or class of chemical). We used a range of approaches to address the questions and draft chemical-specific criteria for rating exposure measurements as Good, Adequate, Poor, or Critically Deficient (Good indicating the least potential for bias in effect estimates due to exposure measurement error).The approaches and key chemical-specific criteria were as follows: For phthalates, based on a comprehensive review of the literature, we identified urine as the preferred biological matrix and emphasized repeat sample collection. For methylmercury we consulted multiple independent researchers with expertise in mercury biomonitoring and found agreement on the importance of standard reference materials and quality control related to mercury adhesion to analytical equipment. For hexavalent chromium, we used existing guidance to develop criteria that take into account uncertainty due to the reduction of hexavalent chromium to trivalent chromium in air and biological samples.Further development of chemical-specific evaluation criteria can enhance the use of standard systematic review tools. The views expressed in this abstract are those of the author and do not necessarily represent the views or policies of the U.S. EPA.

An updated systematic review of epidemiological evidence on hormonal contraceptive methods and HIV acquisition in women

Objective and design:Some studies suggest that specific hormonal contraceptive methods [particularly depot medroxyprogesterone acetate (DMPA)] may increase women's HIV acquisition risk. We updated a systematic review to incorporate recent epidemiological data.Methods:We searched for articles published between 15 January 2014 and 15 January 2016 and hand-searched reference lists. We identified longitudinal studies comparing users of a specific hormonal contraceptive method against either nonusers of hormonal contraception or users of another specific hormonal contraceptive method. We added newly identified studies to those in the previous review, assessed study quality, created forest plots to display results, and conducted a meta-analysis for data on DMPA versus non-use of hormonal contraception.Results:We identified 10 new reports of which five were considered ‘unlikely to inform the primary question’. We focus on the other five reports, along with nine from the previous review, which were considered ‘informative but with important limitations’. The preponderance of data for oral contraceptive pills, injectable norethisterone enanthate, and levonorgestrel implants do not suggest an association with HIV acquisition, though data for implants are limited. The new, higher quality studies on DMPA (or nondisaggregated injectables), which had mixed results in terms of statistical significance, had hazard ratios between 1.2 and 1.7, consistent with our meta-analytic estimate for all higher quality studies of hazard ratio 1.4.Conclusion:Although confounding in these observational data cannot be excluded, new information increases concerns about DMPA and HIV acquisition risk in women. If the association is causal, the magnitude of effect is likely hazard ratio 1.5 or less. Data for other hormonal contraceptive methods, including norethisterone enanthate, are largely reassuring.

P-229 An Evaluation Based on a Systematic Review of Epidemiologic Evidence of Colorectal Cancer Risk among the Alcohol Consuming Indian Population

P-229 An Evaluation Based on a Systematic Review of Epidemiologic Evidence of Colorectal Cancer Risk among the Alcohol Consuming Indian Population

Exposure to non-persistent pesticides and thyroid function: A systematic review of epidemiological evidence.

Numerous pesticides are recognized for their endocrine-disrupting properties. Non-persistent pesticides such as organophosphates, dithiocarbamates and pyrethroids may interfere with thyroid function as suggested by animal studies. However, the influence of chronic exposure to these compounds on thyroidal functions in humans remains to be determined. The present study aimed to review epidemiological evidence for an association between exposure to non-persistent pesticides and circulating levels of thyroid hormones (thyroxin [T4] and triiodothyronine [T3]) and thyroid-stimulating hormone (TSH). A systematic review was conducted using MEDLINE, SCOPUS and Virtual Health Library (BVS) databases. Articles were limited to original studies and reports published in English, Portuguese or Spanish. Nineteen epidemiological studies were identified, 17 of which were cross-sectional, 14 were of occupationally exposed workers and 11 used exposure biomarkers. Fungicides and organophosphates (OP) insecticides were the most studied pesticides. Although methodological heterogeneity between studies was noted, particularly regarding study design, exposure assessment, and control of confounding, most of them showed associations with changes in T3 and T4, and/or TSH levels, while results from a few of these are consistent with experimental data supporting the findings that non-persistent pesticide exposure exerts hypothyroid-like effects. However, reporting quality was moderate to poor in 50% of the studies, particularly regarding method of selection of participants and discussion of external validity. Overall, current knowledge regarding the impact of non-persistent pesticides on human thyroid function is still limited. Given the widespread use of pesticides, future research should assess effects of exposure to currently-used pesticides in cohort studies combining comprehensive questionnaire-based assessment and biomarkers. Investigators need to pay particular attention to exposure during critical windows of brain development and exposure in agricultural populations.

Cigarette smoking and bladder cancer risk: an evaluation based on a systematic review of epidemiologic evidence in the Japanese population.

Although several epidemiological studies have demonstrated that cigarette smoking is an important risk factor for bladder cancer, no systematic review in the Japanese population has yet been performed. Accurate evaluation of bladder cancer risk in relation to smoking for Japanese populations can provide necessary information for Japanese policy-makers and doctors to enlighten the importance of smoking cessation. We reviewed epidemiologic data to estimate the strength of the association between cigarette smoking and bladder cancer in the Japanese population. We identified previous cohort and case-control studies, extracting data from databases in the MEDLINE (PubMed) and Ichushi. The magnitude of association and strength of evidence were evaluated in each study, and a meta-analysis was conducted to obtain summary estimates for the overall magnitude of association. Three cohort and eight case-control studies were identified. Except for one case-control study, all studies showed a strong positive association between cigarette smoking and bladder cancer. The summary relative risk for ever smokers relative to never smokers was 2.14 (95% confidence interval 1.87-2.44) in a fixed-effect model. We conclude that cigarette smoking is a convincing risk factor for bladder cancer among Japanese.

An updated systematic review of epidemiological evidence on hormonal contraceptive methods and HIV acquisition in women

An updated systematic review of epidemiological evidence on hormonal contraceptive methods and HIV acquisition in women

Diabetes mellitus and liver cancer risk: an evaluation based on a systematic review of epidemiologic evidence among the Japanese population.

The potential associations of diabetes mellitus with malignant neoplasms including liver cancer have become a great concern from both clinical and preventive perspectives. Although sufficient evidence for a positive association between diabetes and liver cancer already exists, it would be informative to summarize up-to-date epidemiologic data in Japan. We systematically reviewed epidemiologic studies on diabetes and liver cancer among Japanese populations. Original data were obtained by searching the MEDLINE (PubMed) and Ichushi databases, complemented with manual searches. The evaluation was performed in terms of the magnitude of association in each study and the strength of evidence ('convincing', 'probable', 'possible' or 'insufficient'), together with biological plausibility. We identified 19 cohort studies, one pooled-analysis of seven cohort studies, and seven case-control studies. Of 24 relative risk estimates of liver cancer for diabetes reported in those cohort studies, 17 showed a weak to strong positive association, six revealed no association and one demonstrated a weak inverse association (summary relative risk 2.10, 95% confidence interval 1.60-2.76). Ten relative risk estimates from the case-control studies showed a weak to strong positive association (n = 9) or no association (n = 1; summary relative risk 2.32, confidence interval 1.73-3.12). Overall, the summary relative risk became 2.18 (confidence interval 1.78-2.69). Heterogeneity in relative risks was significant for the difference in categories of study population (P = 0.01), but not in study type (P = 0.39) or sex (P = 0.33). Diabetes mellitus 'probably' increases the risk of liver cancer among the Japanese population.

Meat consumption and colorectal cancer risk: an evaluation based on a systematic review of epidemiologic evidence among the Japanese population.

The association between meat consumption and colorectal cancer remains inconsistent among Asians. The present study systematically evaluated and meta-analyzed epidemiologic studies on the association between consumption of total and specific meats and colorectal cancer risk among Japanese. Original data were obtained from MEDLINE searched using PubMed or from searches of the Ichushi database, complemented with manual searches. The associations were evaluated based on the strength of evidence, the magnitude of association and biologic plausibility. A meta-analysis was performed according to total meat, red and processed meat as well as poultry and site-specific cancers. Six cohort studies and 13 case-control studies were identified. In cohort studies, most investigations found no association between total meat consumption and colon/rectal cancer, and several studies showed a weak-to-moderate positive association of red meat and processed meat consumption with colon/rectal cancer. The majority of case-control studies showed no association between total meat consumption and colon and rectal cancer; however, several ones reported a weak-to-strong positive association of red and processed consumption with colon and rectal cancer. In meta-analysis, the summary relative risks (95% confidence interval) for the highest versus lowest categories of red meat consumption were 1.16 (1.001-1.34) and 1.21 (1.03-1.43) for colorectal and colon cancer, respectively, and those for processed meat consumption were 1.17 (1.02-1.35) and 1.23 (1.03-1.47) for colorectal and colon cancer, respectively. Poultry consumption was associated with lower risk of rectal cancer; summary relative risk (95% confidence interval) was 0.80 (0.67-0.96). High consumption of red meat and processed meat possibly increases risk of colorectal cancer or colon cancer among the Japanese population.

Atrazine and pregnancy outcomes: a systematic review of epidemiologic evidence.

Atrazine (ATR) is a commonly used agricultural herbicide that has been the subject of epidemiologic studies assessing its relation to reproductive health problems. This review evaluates both the consistency and the quality of epidemiologic evidence testing the hypothesis that ATR exposure, at usually encountered levels, is a risk factor for birth defects, small for gestational age birth weight, prematurity, miscarriages, and problems of fetal growth and development. We followed the current methodological guidelines for systematic reviews by using two independent researchers to identify, retrieve, and evaluate the relevant epidemiologic literature on the relation of ATR to various adverse outcomes of birth and pregnancy. Each eligible paper was summarized with respect to its methods and results with particular attention to study design and exposure assessment, which have been cited as the main areas of weakness in ATR research. As a quantitative meta-analysis was not feasible, the study results were categorized qualitatively as positive, null, or mixed. The literature on ATR and pregnancy-related health outcomes is growing rapidly, but the quality of the data is poor with most papers using aggregate rather than individual-level information. Without good quality data, the results are difficult to assess; however, it is worth noting that none of the outcome categories demonstrated consistent positive associations across studies. Considering the poor quality of the data and the lack of robust findings across studies, conclusions about a causal link between ATR and adverse pregnancy outcomes are not warranted.

Soy Intake and Breast Cancer Risk: An Evaluation Based on a Systematic Review of Epidemiologic Evidence Among the Japanese Population

We reviewed epidemiological studies of soy intake and breast cancer among Japanese women. This report is one among a series of articles by our research group, which is evaluating the existing evidence concerning the association between health-related lifestyles and cancer. Original data were obtained from MEDLINE searches using PubMed or from searches of the Ichushi database, complemented with manual searches. Evaluation of associations was based on the strength of evidence and the magnitude of association, together with biological plausibility. Five cohort studies and six case-control studies were identified. Among the cohort studies, two studies observed that total soy intake (in terms of total amounts of soy foods or soy isoflavones) was associated with a moderate (0.5 ≤ relative risk ≤ 0.67 with statistical significance) or strong (relative risk ≤ 0.5 with statistical significance) risk reduction of breast cancer in postmenopausal women. Among the case-control studies, two studies reported a weak (0.67 ≤ odds ratio ≤ 1.5 with statistical significance or 0.5 ≤ odds ratio ≤ 0.67 without statistical significance) inverse association between total soy intake and the risk of breast cancer. In the former, this association was observed in all women combined-premenopausal and postmenopausal women-but in the latter, the association was confined to postmenopausal women. The associations of intakes of individual soy foods with the risk of breast cancer were generally null. There is some evidence that supports the biological plausibility of a protective effect of isoflavones on breast cancer risk. We conclude that soy intake possibly decreases the risk of breast cancer among Japanese women.

Hormonal contraceptive methods and risk of HIV acquisition in women: a systematic review of epidemiological evidence

Hormonal contraceptive methods and risk of HIV acquisition in women: a systematic review of epidemiological evidence