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Table 1 summarizes the characteristics and study quality of the included studies. All studies were cross-sectional, and a total of 74,710 samples were included. The studies were conducted in different countries (China, Korea, America, Croatia, Switzerland, and Spain) and published before 2003, with participants ranging in age from 18 to 80 years. Regarding MetS diagnostic criteria, nine studies used the ATP III guidelines, four studies referenced the IDF guidelines, and one referenced the CDS guidelines. For the SF assay, five studies used chemiluminescence, five studies used immunoradiation, two studies used immunoturbidimetry, and two studies did not describe the specific methods used. According to the AHRQ scale, all included studies were of high or medium quality.
First author, Year Country Study design Age (years) Sex Criteria Ferritin assay Sample size AHRQ score Jehn, 2004[25] America Cross-sectional > 20 Both ATP Ⅲ RIA 5,949 9 Sun, 2008[24] China Cross-sectional 50–70 Both ATP Ⅲ TIA 3,289 7 Cho, 2011[23] Korea Cross-sectional 50a Female ATP Ⅲ RIA 3,082 8 Ryoo, 2011[22] Korea Cross-sectional 41a Male ATP Ⅲ CLIA 18,581 8 Chang, 2013[21] China Cross-sectional > 19 Both ATP Ⅲ NR 2,654 9 Li, 2013[20] China Cross-sectional ≥ 18 Both ATP Ⅲ RIA 8,441 8 Kilani, 2014[19] Switzerland Cross-sectional 53a Both ATP Ⅲ NR 5,498 8 Ledesma, 2015[7] Spain Cross-sectional 19–65 Male ATP Ⅲ TIA 3,386 7 Seo, 2015[18] Korea Cross-sectional 58a Female ATP Ⅲ RIA 280 7 Tang, 2015[6] China Cross-sectional 20–73 Male ATP Ⅲ CLIA 2,417 8 Suarez-Ortegon, 2016[17] Croatia Cross-sectional ≥ 18 Both ATP Ⅲ CLIA 725 8 Shim, 2017[15] Korea Cross-sectional 16–80 Both IDF RIA 15,963 8 Chen, 2017[16] China Cross-sectional 25–74 Both IDF CLIA 2,786 9 Wang, 2020[9] China Cross-sectional 18–75 Both CDS CLIA 1,659 8 Note. ATP III, National Cholesterol Education Program Adult Treatment Panel III; IDF, International Diabetes Federation; CDS, the Guidelines for the Prevention and Treatment of Type 2 Diabetes by Chinese Diabetes Society; CLIA, chemiluminescence immunoassay; RIA, immunoradiometric assay; TIA, immunoturbidimetric assay; NR, Not reported; amean age. Table 1. Characteristics of studies investigating the association between SF and MetS
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The results showed that some heterogeneity existed among the 14 studies (χ2 = 24.69, P = 0.025, I2 = 47.4%). Therefore, a random-effects model was used to combine the effect values. The results showed that SF was positively associated with MetS (OR = 1.77, 95% CI: 1.59–1.98) (Figure 2).
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Subgroup analysis was performed according to the study area, diagnostic criteria, and SF detection method; however, there were significant differences in the subgroups of diagnostic criteria. There were no significant differences for the other subgroups, which indicated that SF could increase the risk of MetS (Table 2).
Subgroup Number of studies OR (95% CI) I2 (%) P-value Region Asia 10 1.75 (1.60–1.91) 57.0 0.782 Europe and America 4 1.79 (1.57–2.04) 19.1 Criteria CDS 1 0.96 (0.50–1.41) − 0.003 IDF 2 1.52 (1.31–1.76) 0 ATP III 13 1.88 (1.73–2.05) 19.8 Ferritin assay CLIA 5 1.88 (1.68–2.11) 50.7 0.140 RIA 5 1.62 (1.41–1.85) 62.3 TIA 2 1.93 (1.60–2.34) 0 NR 2 1.55 (1.28–1.88) 0 Study quality High 11 1.72 (1.59–1.87) 54.3 0.193 Middle 3 1.97 (1.64–2.38) 0 Note. CDS, the Guidelines for the Prevention and Treatment of Type 2 Diabetes by Chinese Diabetes Society; ATP III, National Cholesterol Education Program Adult Treatment Panel III; IDF, International Diabetes Federation; CLIA, chemiluminescence immunoassay; RIA, immunoradiometric assay; TIA, immunoturbidimetric assay; NR, Not reported. Table 2. Subgroup analysis for the association between SF and MetS
The sensitivity analysis showed that the pooled effect sizes obtained for the association of SF with the risk of MetS did not depend on a particular study or group of studies. This finding suggested that the results obtained in this meta-analysis were stable (Supplementary Figure S1 available in www.besjournal.com).
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Since only eight articles provided data on SF and the components of MetS, a meta-analysis of the components was performed for these eight studies[7,9,15,17,20-22,25]. The results showed that SF was positively associated with abdominal obesity (I2 = 52.6%, OR = 1.42, 95% CI: 1.24–1.62), elevated fasting plasma glucose (FPG) (I2 = 78.1%, OR = 1.84, 95% CI: 1.50–2.25), elevated blood pressure (BP) (I2 = 18.4%, OR = 1.17, 95% CI: 1.08–1.26), elevated triglyceride (TG) (I2 = 75.6%, OR = 2.09, 95% CI: 1.72–2.54), and reduced high-density lipoprotein cholesterol (HDL-C) (I2 = 44.4%, OR = 1.33, 95% CI: 1.19–1.49) (Table 3).
Components OR (95% CI) I2 (%) P-value Abdominal obesity 1.42 (1.24–1.62) 52.6 0.039 Elevated FPG 1.84 (1.50–2.25) 78.1 < 0.001 Elevated BP 1.17 (1.08–1.26) 18.4 0.284 Elevated TG 2.09 (1.72–2.54) 75.6 < 0.001 Reduced HDL-C 1.33 (1.19–1.49) 44.4 0.083 Note. FPG, fasting plasma glucose; BP, blood pressure; TG, triglyceride; HDL-C, high-density lipoprotein cholesterol. Table 3. Estimates of risk for the association between SF and the components of MetS from the meta-analysis
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Because of the limited literature available for the dose-response meta-analysis, only seven articles[6,15,16,18,20,22,25] were included. The dose-response relationship between SF and MetS for different sexes is shown in Figure 3. A linear dose-response relationship was found between the two populations (male: P < 0.001, P-nonlinearity = 0.5326, female: P < 0.001, P-nonlinearity = 0.2984). Each 50 μg/L increase in SF in males was associated with a 1.14-fold higher risk of MetS (95% CI: 1.13–1.16). For females, each 50 μg/L increase in SF was associated with a 1.32-fold higher risk of MetS (95% CI: 1.26–1.39). Similar results were obtained for postmenopausal females (P < 0.0001, P-nonlinearity = 0.0673, OR = 1.34, 95% CI: 1.22–1.47) (Supplementary Figure S2 available in www.besjournal.com).
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Publication bias was evaluated by Begg’s rank correlation method and Egger’s regression test. The P-values in the Begg’s test (Figure 4) and the Egger’s test (Figure 5) were 0.381 and 0.512, respectively. These results indicated that the difference was not statistically significant, and publication bias was not evident in the entire study.
Serum Ferritin and the Risk of Metabolic Syndrome: A Systematic Review and Dose-Response Meta-Analysis of Cross-sectional Studies
doi: 10.3967/bes2021.086
- Received Date: 2020-08-20
- Accepted Date: 2020-12-04
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Key words:
- Serum ferritin /
- Metabolic syndrome /
- Meta-analysis /
- Dose-response relationship
Abstract:
Citation: | ZHANG Wei Chun Bai, XING Yang, SHAO Bing. Serum Ferritin and the Risk of Metabolic Syndrome: A Systematic Review and Dose-Response Meta-Analysis of Cross-sectional Studies[J]. Biomedical and Environmental Sciences, 2021, 34(8): 623-631. doi: 10.3967/bes2021.086 |