Background and ObjectiveEmerging evidence from biological and epidemiological studies has suggested that body iron stores and heme-iron intake may be related to the risk of type 2 diabetes (T2D). We aimed to examine the association of body iron stores and heme-iron intake with T2D risk by conducting a systematic review and meta-analysis of previously published studies.Research Design and MethodsSystematic review and subsequent meta-analysis were conducted by searching MEDLINE database up to June 22, 2012 to identify studies that analyzed the association of body iron stores or dietary heme-iron intake with T2D risk. The meta-analysis was performed using the effect estimates and 95% confidence intervals (CIs) to calculate the pooled risk estimates, while the heterogeneity among studies was examined using the I2 and Q statistic.ResultsThe meta-analysis included 16 high-quality studies: 12 studies analyzed ferritin levels (4,366 T2D patients and 41,091 controls) and 4 measured heme-iron intake (9,246 T2D patients and 179,689 controls). The combined relative risk (RR) comparing the highest and lowest category of ferritin levels was 1.66 (95% CI: 1.15–2.39) for prospective studies, 2.29 (95% CI: 1.48–3.54) for cross-sectional studies with heterogeneity (Q = 14.84, p = 0.01, I2 = 66.3%; Q = 44.16, p<0.001, I2 = 88.7%). The combined RR comparing the highest and lowest category of heme-iron intake was 1.31 (95% CI: 1.21–1.43) with heterogeneity (Q = 1.39, p = 0.71, I2 = 0%). No publication bias was found. Additional 15 studies that were of good quality, had significant results, and analyzed the association between body iron stores and T2D risk were qualitatively included in the systematic review.ConclusionsThe meta-analysis and systematic review suggest that increased ferritin levels and heme-iron intake are both associated with higher risk of T2D.
A growing body of evidence indicates that systemic lupus erythematosus (SLE) is associated with increased risk of cognitive impairment and dementia. However, to date, no studies have been conducted to quantitatively summarize and evaluate the consistency of data.Objective:To quantitatively evaluate the relationship of SLE and antiphospholipid antibodies (aPL) with cognitive dysfunction and dementia.Methods:All relevant literature was retrieved from Pubmed, Scopus, and PsycINFO databases. The meta-analysis was performed using effect estimates and 95% confidence intervals (CIs) to calculate pooled risk estimates. The heterogeneity among studies was also examined.Results:The meta-analysis included 11 original studies involving a total of 81,668 patients with dementia and 407 patients with cognitive dysfunction. There were significant associations on fixed-effect models between SLE and dementia (3 studies; RR=1.50; 95% CI=1.37-1.64), SLE and cognitive dysfunction (4 studies; OR=2.97; 95% CI=1.72-5.15), and aPL and cognitive dysfunction (5 studies, OR=1.97; 95% CI=1.55-2.52). We also combined cognitive dysfunction and dementia outcomes as they both represented cognitive impairment. There were significant associations between aPL and cognitive impairment (6 studies; OR=2.03; 95% CI=1.62-2.55), and SLE and cognitive impairment (7 studies; OR=1.83; 95% CI=1.42-2.35). Moderate heterogeneity (I2=45.7%) was found in the association between SLE and cognitive impairment, low heterogeneity (I2=21.8%) in the association between SLE and dementia, and near zero heterogeneity for the other three main analyses.Conclusion:Both SLE and aPL are associated with cognitive impairment.
Dopamine D1 receptor (DRD1) gene is associated with the pathogenesis of myocardial infarction (MI) in aspects of plaque rupture, platelet aggregation, and neutrophil-mediated injury of cardiac myocytes. Thus, the study was designed to explore whether the A-48G polymorphism of the DRD1 gene was associated with MI. The genotype of the DRD1A-48G polymorphism was determined by polymerase chain reaction in the 602 Han Chinese participants, 255 MI patients and 347 controls without MI. A significant association was found between the A-48G polymorphism of DRD1 and MI (genotype model: χ(2)=13.2, unadjusted p=0.001; χ(2)=13.9, adjusted p=0.0002; dominant model: adjusted OR 2.05, 95%CI 1.40-3.00, p=0.0002; recessive model: adjusted OR 2.34, 95%CI 1.01-5.39, p=0.047). The G allele was a risk-increased allele for MI (unadjusted OR 1.83, 95%CI 1.34-2.50, p=0.0001; adjusted OR 1.94, 95%CI 1.40-2.68, p=0.00007). Thus, the study demonstrated the significant association between A-48G polymorphism of the DRD1 gene and MI.
This prospective cohort study aimed to analyze the association between serum ferritin levels and the risk of abnormal glucose metabolism (AGM) in Southwestern Chinese population. The 383 subjects who are aged ≥20 years and free of AGM at baseline between in 2007 and in 2008 were included in Southwestern China, and their baseline serum ferritin levels were measured. Among these subjects, 140 subjects were developed into AGM during the follow-up (2008-2012). In logistic regression models, the relative risk in the top versus that in the lowest quartile of serum ferritin levels was 2.86 (p = 0.013) in females and 3.50 (p = 0.029) in males after adjusting the age, gender, family history of diabetes, current smoking, and alcohol; however, serum ferritin levels were not significantly associated with incident of AGM after controlling for metabolic factors (waist circumference, systolic pressure (SBP), triglyceride (TG), and homeostasis model assessment formula insulin resistance (HOMA-IR)). Elevated serum ferritin levels are associated with AGM but not an independent risk factor.
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