Data Analyses

Data was analyzed using SAS 9.3 for Windows. Descriptive statistics, including the means, standard deviations, and ranges, were calculated. To examine the influence of race, t-tests were calculated to compare the Black adolescents with SCD to the control group of healthy Black adolescents on the sleep variables. Then to assess for possible covariates for the subsequent regression analyses, chi-squares and t-tests were calculated comparing adolescents with SCD to the healthy control group of adolescents on sex and age. To test the hypothesis that, over and above the impact of age, sex, and race, SCD would place adolescents at increased risk of poor sleep patterns, a series of regression models predicting sleep variables using SCD status, age, and sex were calculated with the combined sample of adolescents with and without SCD. To explore the relationship between socio-demographic, physical, and disease-related factors and sleep problem risk, correlations and t-tests were calculated between the variables of interest within the sample of adolescents with SCD.