highly significantP -value ≤ 10 −6
Briefly, meta-analyses were considered to be supported by robust evidence if the association was supported by more than 1000 cases, a highly significant association (the random effects model had a P -value ≤ 10 −6 , a threshold that is considered to substantially reduce false positive findings) [ 31 – 33 ], there was absence of high heterogeneity based on I 2 < 50%, the 95% PI excluded the null value, and there was no evidence of small-study effects or excess statistical significance.