association study confusion

[alt42]

hi all,

i'm trying to include some population genetics information in a paper i'm currently writing and i've come across a problem with a paper i'd like to use. the pubmed link is as follows (i don't know if i am allowed to attach the paper itself):

http://www.ncbi.nlm.nih.gov/pubmed/16804517?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum

Now for my two questions:

1.) what is the difference between relative risk (RR) and genotype relative risk (GRR)?

2.) what do the numbers under the different models in table 2 mean? why does recessive model have infinity for each study included in the meta-analysis?

i'm thinking the values i asked about above describe the likelyhood of each model but how do i know which ones are significant and which ones are not

also could someone rephrase part of the caption in table 2?

"M vs W allele for the multiplicative model, MM and MW vs WW for the dominant model and MM vs MW and
WW for the recessive model"

I would appreciate any help that you guys/gals can offer

Thank you

[alt42]

Ok i think i've got most of this figured out except for the infinity part in table 2