• Journal of Preventive Medicine and Public Health
• /
• v.34 no.3
• /
• pp.262-268
• /
• 2001

Objectives : To integrate the results of studies which assess an association between blood lead and blood pressure. Methods : We surveyed the existing literature using a MEDLINE search with blood lead and blood pressure as key words, including reports published from January 1980 to December 2000. The criteria for quality evaluation were as follows: 1) the study subjects must have been workers exposed to lead, and 2) both blood pressure and blood lead must have been measured and presented with sufficient details so as to estimate or calculate the size of the association as a continuous variable. Among the 129 articles retrieved, 13 studies were selected for quantitative meta-analysis. Before the integration of each regression coefficient for the association between blood pressure and blood lead, a homogeneity test was conducted. Results : As the homogeneity of studies was rejected in a fixed effect model, we used the results in a random effect model. Our quantitative meta-analysis yielded weighted regression coefficients of blood lead associated with systolic blood pressure and diastolic blood pressure results of 0.0047 (95% confidence interval [CI]: -0.0061, 0.0155) and 0.0004 (95% CI: -0.0031, 0.0039), respectively. Conclusions : The published evidence suggested that there may be a weak positive association between blood lead and blood pressure, but the association is not significant.

• Nutrition Research and Practice
• /
• v.17 no.1
• /
• pp.62-72
• /
• 2023

BACKGROUND/OBJECTIVES: Many studies have revealed an association between fat mass and the obesity-related gene (FTO) and obesity. On the other hand, no meta-analysis was conducted with data from only Koreans. Therefore, this study performed a meta-analysis using Korean data to provide evidence for the association between FTO single nucleotide polymorphisms (SNPs) and the risk of obesity among Korean adults. SUBJECT/METHODS: Meta-analysis was finally conducted with data extracted from seven datasets of four studies performed on Korean adults after the screening passed. Five kinds of FTO SNPs (rs9939609, rs7193144, rs9940128, rs8050136, and rs9926289) were included, and the relationship between FTO SNPs and body mass index (BMI) was investigated using linear regression with an additive model adjusted for covariants, such as age, sex, and area. RESULTS: The minor alleles of FTO SNPs were associated with increased BMI (odds ratio [OR], 1.31; 95% confidence interval [CI], 1.21-1.42). In sub-group analysis, FTO rs9939609 T>A was significantly associated with BMI (OR, 1.23; 95% CI, 1.06-1.42). The other FTO SNPs together were significantly associated with BMI (OR, 1.37; 95% CI, 1.25-1.49). The publication bias was not observed based on Egger's test. CONCLUSIONS: This meta-analysis showed that minor alleles in the FTO SNPs were significantly associated with an increased BMI among Korean adults. This meta-analysis is the first to demonstrate that minor alleles in the FTO SNPs contribute significantly to the increased risk of obesity among Korean adults using data from a Korean population.

• Journal of Technology Innovation
• /
• v.19 no.3
• /
• pp.141-174
• /
• 2011

This paper presents the results of a meta-regression analysis on econometric evidence concerning the relationship between public funding of R&D and private R&D expenditure by reviewing literature and synthesizing existing results. The analysis on the effects of public financing on private investments in R&D has been the object of numerous studies, none of which having arrived at definite conclusion. A meta-analysis based upon a data-base including all relevant studies was carried out to examine whether the characteristics of the applied analysis influence the results. Three different empirical results are presented.

• The Korean Journal of Pain
• /
• v.30 no.4
• /
• pp.250-257
• /
• 2017

Vitamin D is a cofactor responsible for autoimmune disorders. There is no agreement in the studies investigating the association between vitamin D and fibromyalgia. This study aims to combine the conflicting results of the primary studies which compared these patients with control groups regarding the serum concentration of vitamin D. This meta-analysis has been designed based on PRISMA guidelines. Relevant keywords were searched in PubMed, Science direct, Scopus, Cochrane, and Google scholar and primary studies were selected. After screening the eligible studies according to inclusion/exclusion criteria, we investigated the risk of bias in the selected studies and also the heterogeneity between the primary results using Cochrane (Q) and I-squared ($I^2$) indices. The primary results were combined using inverse variance method and Cohen statistics as well as a random effects model. Publication bias was assessed using Egger test. Sensitivity analysis was applied to investigate the influence of each primary study on the final result of the meta-analysis. Suspected factors in the heterogeneity were assessed using meta-regression models. We entered 12 eligible studies in the meta-analysis including 851 cases compared with 862 controls. The standardized mean difference of Vitamin D between the two groups was -0.56 (95% confidence interval: -1.05, -0.08). Our meta-analysis showed that vitamin D serum levels of patients with fibromyalgia was significantly lower than that of control group.

• Environmental and Resource Economics Review
• /
• v.16 no.1
• /
• pp.65-98
• /
• 2007

Wetland provides various environmental services as well as marketable goods to human society. This paper presents a meta-analysis of the wetland valuation studies conducted in Korea during the past decade. Meta-analysis is a technique of summarizing research results from the separate but related studies using statistical methods. The objectives of the paper is to identify the main factors affecting the wetland values and to examine the applicability of meta-regression analysis for summarizing the information from valuation studies of natural ecosystem. The total of 64 observations from 24 studies are assembled, and we observe significant differences in wetland values depending on the characteristics of the studies. With the statistical significance, our results indicate that the method employed affects the wetland values while the wetland function evaluated affects little. In addition, we found that the size of wetland is negatively associated with the values, implying that wetland values exhibit the decreasing returns to scale. The evidences from our empirical analysis suggest that the meta-analysis has a potential as a tool to synthesize the research results from valuation studies and to provide useful information to policy makers. However, this study acknowledges that more effort should be dedicated toward the construction of DB on valuation studies as well as the research on the model improvement to enhance the validity and reliability of meta-analysis.

• Journal of Korean Society of Rural Planning
• /
• v.29 no.4
• /
• pp.191-200
• /
• 2023

This study aims to estimate the value of environmental services that could be generated by seawater flowing in the Geumgang Estuary by using meta-regression for benefit transfer. The environmental services that can be generated by seawater flowing are assumed to be improved water quality, increased biodiversity, and enhanced water-friendly effect. The analysis was conducted using 122 data from 28 studies from EVIS. The results show that households in the neighborhood where seawater is distributed are willing to pay about KRW 46,918, KRW 7,752, and KRW 7,859 per year for improved water quality, increased biodiversity, and enhanced water-friendly, respectively. The WTP of the national households other than neighboring households was found to be KRW 19,401, KRW 3,206, and KRW 3,250 for the three environmental services, respectively. The WTP for water quality improvement is higher than that for biodiversity increase and water-friendly effect increase, which may be due to the fact that water quality improvement is an environmental service that is close to the use value. In addition, neighboring households have a higher WTP than national households because neighboring households are more likely to evaluate the benefits of seawater flowing as a use value, while national households are more likely to evaluate it as a non-use value.

• Nutrition Research and Practice
• /
• v.4 no.5
• /
• pp.375-382
• /
• 2010

The precise effects of protein intake on fractional synthesis rate (FSR) of muscle protein are still under debate. The sample size of these studies was small and the conclusions in young and elderly subjects were inconsistent. To assess the effect of dietary protein intake on the FSR level, we conducted a meta-analysis of controlled protein intake trials. Random-effects models were used to calculate the weighted mean differences (WMDs). Ten studies were included and effects of short-term protein intake were evaluated. In an overall pooled estimate, protein intake significantly increased the FSR (20 trials, 368 participants; WMD: 0.025%/h; 95%CI: 0.019-0.031; P < 0.0001). Meta-regression analysis suggested that the protein dose was positively related to the effect size (regression coefficient = 0.108%/h; 95%CI: 0.035, 0.182; P = 0.009). A subgroup analysis indicated that protein intake significantly increased FSR when the protein dose was ${\leq}$ 0.80 g/kg BW (16 trials, 308 participants; WMD: 0.027%/h; 95%CI: 0.019-0.031; P < 0.0001), but did not affect FSR when the protein dose was > 0.80 g/kg BW (4 trials, 60 participants; WMD: 0.016%/h; 95%CI: 0.004-0.029; P = 0.98). In conclusion, this study is the first integrated results showing that a short-term protein intake is effective at improving the FSR of muscle protein in the healthy elderly as well as young subjects. This beneficial effect seems to be dose-dependent when the dose levels of protein range from 0.08 to 0.80 g/kg BW.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.13
• /
• pp.5161-5166
• /
• 2014

Our aim was to access the association between recreational physical activity (RPA) and risk of ovarian cancer (OC). The studies were retrieved from the PubMed and Embase databases up to February 20th, 2014. Risk ratios (OR) and 95% confidence intervals (CI) were used to estimate effect sizes. Random-effects or fixed-effects models were used to pool the data. The trim and fill method was applied for sensitivity analysis. Begg's rank correlation test and Egger's regression asymmetry test were employed to assess the publication bias. A total of 6 studies (435398 participants including 2983 OC patients) were included in this meta-analysis. The overall estimate indicated that there was weakly inverse association between RPA and OC risk (RR=0.90, 95%CI: 0.72-1.12, p=0.335). Meanwhile, for prospective cohort studies, a result consistent with the overall estimate was obtained (RR=1.12, 95% CI: 0.88-1.42, p=0.356). However, for case control studies, the pooled estimate of RR was 0.76 (95%CI: 0.64-0.90, p=0.002), indicating a clear significant association between RPA and OC risk. In addition, the sensitivity analysis indicated a significant link between RPA and risk of OC after removing Lahmann's study (RR=0.80, 95% CI: 0.68-0.93, p=0.004). No significant publication bias was found (Begg's test: p=1.00; Egger's test: p=0.817). In conclusion, our meta-analysis indicated a weakly inverse relationship between RPA and the occurrence of OC.

• Journal of the Korea Convergence Society
• /
• v.7 no.5
• /
• pp.145-153
• /
• 2016

The purpose of this study was using a meta-analysis to estimate effect size ACT intervention program. Using a statistical method, meta-analysis has advantages that prove intervention's amount and direction. Meta-analysis facilitates comprehensive analysis. Through the data collection, 43studies were selected and 183 effect size were calculated as analysis objects. Using a 183 effect size, the overall effect size, Effect Size of categorical Factor, meta-regression result were suggested. The overall effect size of ACT program was 0.704. In the effect area of ACT, the affective domain had the largest effect size. Next were the cognitive domain, the behavioral domain. Analysis on gender of participant, mixed group had the largest effect size. Next were the female grouop, male group. Analysis on age of participant, adult group had the largest effect size. Next were the undergraduate grouop, adolescent group. Based on the findings, implications for future study were discussed.

• Korean Journal of Veterinary Research
• /
• v.44 no.4
• /
• pp.669-676
• /
• 2004

To evaluate the diagnostic accuracy of two commercial ELISA tests (Allied- and CSL-ELISA) for the diagnosis of Mycobacterium paratuberculosis in cattle, Meta-analysis using English language papers published during 1990-2001 was performed. Diagnostic odds ratios (DOR) were analyzed using regression analysis together with summary receiver operating characteristic (ROC) curves. The difference in diagnostic performance between the two ELISA systems was evaluated by using linear regression. Publication bias was assessed by funnel plot and linear regression. The pooled sensitivity and specificity were 44% (95% CI, 38 to 51) and 98% (95% CI, 96 to 99) for the random-effect model. The DOR between studies was heterogeneous. The area under the fitted ROC curve (AUC) was 0.72 for the unweighted and 0.77 for the weighted model. Maximum joint sensitivity and specificity for the unweighted and weighted model from their summary ROC curve were 70% and 75%, respectively. Based on the fitted model, at a specificity of 95%, sensitivity was estimated to be 52% for the unweighted and 57% for the weighted model. From the final multivariable model study characteristic, the country was the only significant variable with an explained component variance of 13.3%. There were no significant differences in discriminatory power, sensitivity, and specificity between the two ELISA tests. The overall diagnostic accuracy of two commercial ELISA tests was moderate, as judged by the AUC, maximum joint sensitivity and specificity, and estimates from the fitted model and clinical usefulness of the tests for screening program is limited because of low sensitivity and heterogeneous of DOR. It is, therefore, recommended to use ELISA tests as a parallel testing with other diagnostic tests together to increase test sensitivity in the screening program.