Figure 2. Associations of insulin-like growth factor (IGF)–determining single nucleotide polymorphism (SNP) genotypes with Alzheimer disease (AD) risk, International Genomics of Alzheimer's Project data (n = 17,008 cases; 37,154 controls).

A combined estimate and its 95% confidence interval from fixed-effects meta-analysis is shown by the diamond's central position and lateral width, respectively, along with the test statistic of heterogeneity between individual estimates (I²). Gray boxes around point estimates indicate the weighting of results in the overall estimate.