Validating the factor structure and reliability of the sleep quality scale in a community-based study in Ibadan,...

The sleep quality scale (SQS) is a comprehensive multidimensional sleep assessment scale used to evaluate sleep quality (SQ) among adults in the general population. However, the scale is yet to be validated among indigenous African populations such as in Nigeria. This study validated the factor structure and evaluated the reliability of a previously developed SQS among community-based adults in Ibadan, Nigeria.

Data on SQ was extracted from 3,635 adult (≥18 years) from the Community-based Investigation of the Risk Factors for Cardiovascular Disease (COMBAT-CVDs) study. Cronbach-alpha (α) was used to evaluate the internal consistency or reliability of the SQS (>50 % cut-off), while the original 6-factor model of the SQS was explored using exploratory (≥0.5 cut-offs) and confirmatory factor analyses. The chi-square goodness of fit test and multiple fit indices were used to assess model fit at a two-sided P < 0.05.

Overall, the participant's mean age was 35.33±15.20 years, and 54.60 % were male. The overall reliability estimate for the SQS was 86.00 %, while the restoration after sleep subscale reliability was 93.00 %. The exploratory and confirmatory factor analysis showed that the original 6-factor model of the SQS is a more plausible model for this sample of community-based adults: comparative fit index >0.92, Tucker-Lewis index > 0.91, root mean square error of approximation ≤ 0.05.

Our findings revealed that the SQS is promising for population-based assessment of SQ and may also assist in identifying sleep-related disorders and monitoring the efficacy of sleep treatment among indigenous Africans.