Descriptive statistics such as percent frequencies for categorical data and means and standard deviations for continuous data were computed. As most data were not normally distributed, Spearman rank correlations were computed to investigate the interrelationships between measures. Step-wise regression techniques, both linear and logistic, were used to model factors of interest with inclusion/exclusion criteria of P < 0.15. Statistical analysis was performed using SAS v9.1 computer software package. The significance level was set at P < 0.05