Supplemental Material for Combating Unmeasured Confounding in Cross-Sectional Studies: Evaluating Instrumental-Variable and Heckman Selection Models

2014 ◽  
Keyword(s):  
Instrumental Variable ◽  
Cross Sectional ◽  
Unmeasured Confounding ◽  
Selection Models ◽  
Cross Sectional Studies ◽  
Heckman Selection

scholarly journals The Effect of Prophylactic HPV Vaccines on Oral and Oropharyngeal HPV Infection—A Systematic Review

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1339
Author(s):  
Kristoffer Juul Nielsen ◽  
Kathrine Kronberg Jakobsen ◽  
Jakob Schmidt Jensen ◽  
Christian Grønhøj ◽  
Christian Von Buchwald
Keyword(s):  
Cohort Study ◽  
Oropharyngeal Cancer ◽  
Hpv Infection ◽  
Case Control ◽  
Igg Antibodies ◽  
Hpv Vaccines ◽  
Case Control Studies ◽  
Cross Sectional ◽  
Post Vaccination ◽  
Cross Sectional Studies

Human papillomavirus (HPV) imposes an increased risk of developing cervical, anal and oropharyngeal cancer. In the Western world, HPV infection is currently the major cause of oropharyngeal cancer. The effectiveness of HPV vaccines for oral or oropharyngeal HPV infection is yet to be determined. This study conducted a systematic literature search in Pubmed and Embase. Studies investigating the impact of HPV vaccines on oral or oropharyngeal HPV infection were enrolled. This review reports the relative prevention percentage (RPP), including a risk of bias assessment as well as a quality assessment study. Nine studies were included (48,777 participants): five cross-sectional studies; one randomized community trial study (RCT); one longitudinal cohort study; and two case-control studies. A significant mean RPP of 83.9% (66.6–97.8%) was calculated from the cross-sectional studies, 82.4% in the included RCT and 83% in the longitudinal cohort study. Further, two case-control studies that measured antibody response in participants immunized with HPV vaccines were included. Respectively, 100% and 93.2% of participants developed HPV-16 Immunoglobulin G (IgG) antibodies in oral fluids post-vaccination. Analysis of the studies identified a significant decrease in vaccine-type oral or oropharyngeal HPV infections in study participants immunized with HPV vaccines across study designs and heterogenous populations. Further, a significant percentage of participants developed IgG antibodies in oral fluid post-vaccination.

scholarly journals Knowledge of blood donation and associated factors in Ethiopia: a systematic review and meta-analysis

BMJ Open ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. e044343
Author(s):  
Addisu Getie ◽  
Adam Wondmieneh ◽  
Melaku Bimerew ◽  
Getnet Gedefaw ◽  
Asmamaw Demis
Keyword(s):  
Systematic Review ◽  
Associated Factors ◽  
Blood Donation ◽  
Meta Analysis ◽  
Educational Status ◽  
Sensitivity Analyses ◽  
Cross Sectional ◽  
Level Of Knowledge ◽  
Cross Sectional Studies ◽  
Study Participants

ObjectiveTo assess the level of knowledge about blood donation and associated factors in Ethiopia.DesignSystematic review and meta-analysis.MethodsBoth published and unpublished cross-sectional studies on the level of knowledge about blood donation in Ethiopia were included. Articles from different databases such as PubMed/MEDLINE, HINARI, EMBASE, Scopus, Google Scholar and African Journals Online were searched. Cochrane I2 statistics were used to check for heterogeneity. Subgroup and sensitivity analyses of evidence of heterogeneity were carried out. Egger’s test with funnel plot was conducted to investigate publication bias.ResultTwenty cross-sectional studies with a total of 8338 study participants (4712 men and 3626 women) were included. The overall nationwide level of knowledge about blood donation was 56.57% (95% CI 50.30 to 62.84). Being in secondary school and above (adjusted OR=3.12; 95% CI 2.34 to 4.16) and being male (adjusted OR=1.81; 95% CI 1.44 to 2.28) were the factors associated with level of knowledge about blood donation.ConclusionMore than half of the study participants were knowledgeable about blood donation. Sex and educational status were the factors significantly associated with level of knowledge about blood donation in Ethiopia. Therefore, there is a need for education and dissemination of information about blood donation among the general population to build adequate knowledge and maintain regular blood supply.

scholarly journals Association between Metabolic Syndrome Components and Cardiac Autonomic Modulation among Children and Adolescents: A Systematic Review and Meta-Analysis

Biology ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 699
Author(s):  
Rashmi Supriya ◽  
Fei-Fei Li ◽  
Yi-De Yang ◽  
Wei Liang ◽  
Julien S. Baker
Keyword(s):  
Risk Factors ◽  
Young People ◽  
Correlation Coefficient ◽  
High Frequency ◽  
Meta Analysis ◽  
Low Frequency ◽  
Autonomic Modulation ◽  
Cross Sectional ◽  
Cross Sectional Studies ◽  
Positive Correlations

Background: the clustering of metabolic syndrome (MetS) risk factors is becoming more prevalent in children, leading to the development of type 2 diabetes (T2D) and cardiovascular diseases in early adulthood. The impact of MetS risk factors on cardiac autonomic modulation (CAM) or vice versa has been noted to track from childhood to pre-adolescence and adolescence. Understating associations in this age group may help to improve the clinical outcomes of the MetS, even when MetS symptoms are not visible. Potential damage from each individual MetS component and the ability to predict early cardiac damage or upcoming cardiovascular events is very important. Therefore, the present systematic review and meta-analysis investigated the associations between CAM and MetS risk factors individually to verify which of the MetS risk components were significantly correlated with heart rate variability (HRV) indices before or at the onset of the MetS among young people. The purpose of this review was to outline the importance of potentially screening HRV indices in young people even with only one MetS risk factor, as a pre-indicator for early cardiovascular risk stratification. Methods: cross-sectional studies that examined the relationship of MetS risk factors with HRV indices were searched using four databases including PubMed, the Cochrane clinical trials library, Medline and the Web of Science. Correlation coefficients with 95% confidence intervals (95% CI), and random effects meta-analyses of the association between MetS risk factors with HRV indices were performed. Results: out of 14 cross-sectional studies and one case-control study, 8 studies (10 data sets) provided association data for the meta-analysis. Our results indicated significant positive correlations for systolic blood pressure (SBP) (correlation coefficient 0.13 (95%CI: 0.06; 0.19), I2 = 47.26%) and diastolic blood pressure (DBP) (correlation coefficient 0.09 (95%CI: −0.01; 0.18), I2 = 0%) with a Low Frequency/High Frequency ratio (LF/HF). Significant negative correlations for waist circumference (WC) (correlation coefficient −0.12 (95%CI: −0.19; −0.04), I2 = 51.50%), Triglycerides (TGs) (correlation coefficient −0.09 (95%CI: −0.15; −0.02), I2 = 0%) and ≥2 MetS risk factors (correlation coefficient −0.10 (95%CI: −0.16; −0.03), I2 = 0%); with high frequency (HF) were revealed. Significant positive correlations for high density lipoprotein (HDL) (correlation coefficient 0.08 (95%CI: 0.05; 0.11), I2 = 0%) and significant negative correlations of ≥2 MetS risk (correlation coefficient −0.04 (95%CI: −0.12; 0.03), I2 = 0.0%) with low frequency (LF) were revealed. Significant negative correlations for TGs (correlation coefficient −0.09 (95%CI: −0.23; 0.05), I2 = 2.01%) with a mean square root of the sum of differences between mean time between two successive intervals (rMSSD) and significant positive correlation of HDL (correlation coefficient 0.09 (95%CI: −0.01; 0.19), I2 = 0.33%) with standard deviation of the time between two successive intervals (SDNN) were also revealed. An Egger’s test indicated that there was no obvious publication bias for any of the above relationships except for TGs and rMSSD. The significance level stipulated for the meta-analysis was p < 0.05. Conclusions: lipid profiles (HDL and TGs), WC and BP were associated with CAM in young people up to the age of 19 years. The use of HRV indices to predict future MetS risk, and relationships with individual risk factors including HDL, BP, WC and TGs, were established. Future studies related to young people (up to the age of 19 years) are recommended to explore the associations reported here further.

scholarly journals The Epidemiological Characteristics of Late-Onset Hypogonadism in Chinese Middle-Aged and Elderly Men: Two Cross-Sectional Studies in the Same Community

2020 ◽  
Vol 14 (6) ◽  
pp. 155798832097799
Author(s):  
Shan-Jie Zhou ◽  
Ming-Jia Zhao ◽  
Yi-Hong Yang ◽  
Di Guan ◽  
Zhi-Guang Li ◽  
...  
Keyword(s):  
Late Onset ◽  
Community Dwelling ◽  
Total Testosterone ◽  
Middle Aged ◽  
Cross Sectional ◽  
Cutoff Values ◽  
Significant Difference ◽  
Cross Sectional Studies ◽  
Late Onset Hypogonadism ◽  
Epidemiological Characteristics

The purpose of this study was to investigate the prevalence and epidemiological characteristics of late-onset hypogonadism (LOH) in middle-aged and elderly Chinese men. Two cross-sectional studies were conducted at 5-year intervals in community-dwelling men living in the same area. A total of 1472 (Study 1, S1) and 944 (Study 2, S2) men aged 40–69 years old were recruited as subjects. Subjects were evaluated through combining serum reproductive hormone levels with the Androgen Deficiency in Aging Males (ADAM) questionnaire and the Aging Males’ Symptoms (AMS) scale. A significant difference was found in mean testosterone deficiency (TD) prevalence between S1 and S2, using either serum total testosterone (TT; 14.02% vs. 6.36%) or serum calculated free testosterone (cFT; 43.69% vs. 16.53%) cutoff values. According to the S1 or S2 data, the mean prevalence of LOH was 37.85%/15.47% in the positive ADAM test and 15.42%/9.43% in the positive AMS test ( p < .01). According to classifications of TD based on gonadal status, the prevalence of secondary TD (27.34%) was higher than the primary (16.36%) and compensated (15.42%) TD in S1 ( p < .01). However, there were significant differences among the prevalence of primary (6.89%), secondary (9.64%), and compensated (27.65%) TD in S2 ( p < .05). Different types of testosterone levels, TD cutoff values, and questionnaires influenced the prevalence of TD and LOH. The serum FT cutoff value was an optimal threshold for evaluating and diagnosing TD and LOH, whose prevalence increased gradually with male aging.

Serum uric acid levels and risk of prehypertension: a meta-analysis

2017 ◽  
Vol 55 (3) ◽  
Author(s):  
Menglin Jiang ◽  
Dandan Gong ◽  
Yu Fan
Keyword(s):  
Uric Acid ◽  
Serum Uric Acid ◽  
Meta Analysis ◽  
Elevated Serum ◽  
China National Knowledge Infrastructure ◽  
Cross Sectional ◽  
Knowledge Infrastructure ◽  
Increased Risk ◽  
Cross Sectional Studies ◽  
The Relationship

AbstractElevated serum uric acid (SUA) levels may increase the risk of prehypertension. However, the findings from these studies remain conflicting. The objective of this study was to determine the relationship between SUA levels and risk of prehypertension by conducting a meta-analysis. We conducted a comprehensive literature search of PubMed, Embase, China National Knowledge Infrastructure, VIP, and the Wangfang database without language restrictions through May 2015. Observational studies assessing the relationship between SUA levels and prevalence of prehypertension were included. Pooled adjust odds ratio (OR) and corresponding 95% confidence intervals (CI) of prehypertension were calculated for the highest vs. lowest SUA levels. Prehypertension was defined as systolic blood pressure (BP) ranging from 120 to 139 mmHg or diastolic BP ranging from 80 to 89 mmHg. Eight cross-sectional studies with a total of 21,832 prehypertensive individuals were included. Meta-analysis showed that elevated SUA levels were associated with increased risk of prehypertension (OR: 1.84; 95% CI: 1.42–2.38) comparing the highest vs. lowest level of SUA levels. Subgroup analyses showed that elevated SUA levels significantly increased the risk of prehypertension among men (OR: 1.60; 95% CI: 1.12–2.21) and women (OR: 1.59; 95% CI: 1.17–2.16). Elevated SUA levels are positively associated with the risk of prehypertension in the general population. However, more well-designed longitudinal studies are needed before a definitive conclusion can be drawn due to the cross-sectional studies included are susceptible to bias.

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