Figure 1.
Selection of studies for meta-analysis.
Table 1.
Characteristics of all identified studies (N = 16) of ferritin levels, iron intake and the risk of type 2 diabetes for the meta-analysis.
Table 2.
Assessment of quality of all included studies for systematic review and meta-analysis.
Table 3.
Characteristics of additional identified studies (N = 15) of body iron stores and the risk of T2D for the systematic review.
Table 4.
Effect Estimates of type 2 diabetes according to ferritin levels and dietary iron intake in all 16 studies for the meta-analysis.
Figure 2.
Forest plot showing the effect estimates of each prospective study and the pooled relative risk comparing the highest with the lowest category of ferritin levels.
*dotted line represented the combined effect estimate of meta-analysis. Size of square and rhomboids represented weight.
Figure 3.
Forest plot showing the effect estimates of each cross-sectional study and the pooled relative risk comparing the highest with the lowest category of ferritin levels.
*dotted line represented the combined effect estimate of meta-analysis. Size of square and rhomboids represented weight.
Figure 4.
Forest plot showing the effect estimates of each cohort study and the pooled relative risk comparing the highest with the lowest category of heme-iron intake levels.
*dotted line represented the combined effect estimate of meta-analysis. Size of square and rhomboids represented weight.
Table 5.
Stratified meta-analysis of ferritin levels and the risk of type 2 diabetes.
Table 6.
β coefficients and corresponding p values analyzed by meta-regression models.
Figure 5.
Begg’s Funnel Plots for visual assessment of the presence of publication bias for 6 prospective studies of ferritin in the meta-analysis.
Begg’s bias (P = 0.851).
Figure 6.
Egger’s Funnel Plots for visual assessment of the presence of publication bias for 6 prospective studies of ferritin in the meta-analysis.
Egger’s bias (P = 0.772).
Figure 7.
Begg’s Funnel Plot for visual assessment of the presence of publication bias for 6 cross-sectional studies of ferritin in the meta-analysis.
Begg’s bias (P = 0.188).
Figure 8.
Egger’s Funnel Plot for visual assessment of the presence of publication bias for 6 cross-sectional studies of ferritin in the meta-analysis.
Egger’s bias (P = 0.124).
Figure 9.
Begg’s and Funnel Plot for visual assessment of the presence of publication bias for 4 cohort studies of heme-iron intake in the meta-analysis.
Begg’s bias (P = 0.497).
Figure 10.
Egger’s Funnel Plot for visual assessment of the presence of publication bias for 4 cohort studies of heme-iron intake in the meta-analysis.
Egger’s bias (P = 0.658).
Figure 11.
Galbraith plot of the ferritin levels for the association with type 2 diabetes for prospective studies.
The regression runs through the origin interval (central solid line). Between the two outer parallel lines is the 95% confidence interval.
Figure 12.
Galbraith plot of the ferritin levels for the association with type 2 diabetes for cross-sectional studies.
The regression runs through the origin interval (central solid line). Between the two outer parallel lines is the 95% confidence interval.