uniqid = Unique SNP identifier based on chr, position and the alleles (alphabetically ordered)
chr = Chromosome
bp = Hg19 position 
a1 = Effect allele 
a2 = Other allele 
beta = Effect size 
se = Standard error
pval = P value 
N = Sample Size 
af = Effect allele frequency 
oldID = rs'id 
info = Imputation Quality
zval = beta/se