Statistical analysis
Allele and genotype frequencies of each SNP were determined by direct
counting. Genotype and allele frequencies between groups were compared
using the χ2 test and Fisher’s exact test when
appropriate. For allelic associations, p values with Yates correction
and odds ratio (OR) with 95% confidence intervals (CI) were calculated
using Statcalc program (Epiinfo version 6.0.4, CDC, Atlanta, GA).
Pair-wise LD (D’, r2) was estimated by use of
Haploview software version 4.2. Chi-square tests were performed for
categorical data, while student’s t -test (or Mann Whitney U test
when appropriate) were performed for comparison of continuous data.
Differences in means with a significance value (p<0.05) were
considered significant. Standard errors (and/or deviations) of treatment
means were also calculated.