approached significanceP =0.09
The CHD incidence rate was increased at the highest level of GI exposure (mean GI of 84.4 GI units, range 79.9 to 91) relative to the lowest (mean GI of 72.3 GI units, range 68.1 to 77), RR=1.11, 95% CI 0.99 to 1.24, and approached significance ( P =0.09) but with significant evidence of heterogeneity (I 2 =45%, P =0.05).