Study on the development of an infectious disease-specific health literacy scale in the Chinese population

To develop a scale to assess infectious disease-specific health literacy (IDSHL) in China and test its initial psychometric properties.

Item pooling, reduction and assessment of psychometric properties were conducted. The scale was divided into 2 subscales; subscale 1 assessed an individual's skills to prevent/treat infectious diseases and subscale 2 assessed cognitive ability. In 2014, 9000 people aged 15-69 years were randomly sampled from 3 provinces and asked to complete the IDSHL questionnaire. Cronbach's α was calculated to assess reliability. Exploratory factor analysis, t-test, correlations, receiver operating characteristic (ROC) curve and logistic regression were used to examine validity.

Each of the 22 items in subscale 1 had a content validity index >0.8. In total, 8858 people completed the scale. The principal components factor analysis suggested a 5-factor solution. All factor loadings were >0.40 (p<0.05). The IDSHL score was 22.07±7.91 (mean±SD; total score=38.62). Significant differences were observed across age (r=-0.276), sex (males: 21.65±8.03; females: 22.47±7.78), education (14.16±8.19 to 26.55±6.26), 2-week morbidity (present: 20.62±8.17, absent: 22.35±7.83; p<0.001) and health literacy of the highest and lowest 27% score groups (all p<0.05). The ROC curve indicated that 76.2% of respondents were adequate in IDSHL. Binary logistic regression analysis revealed 12 predictors of IDSHL adequacy (p<0.05). Among the 22 remaining items, Corrected Item-Total Correlation ranged from 0.316 to 0.504 and Cronbach's α values ranged from 0.754 to 0.810 if the items were deleted. The overall α value was 0.839 and the difficulty coefficient ranged from 1.19 to 4.08. For subscale 2, there were statistically significant differences between the mean scores of those with a correct/incorrect answer (all p<0.001).

The newly developed 28-item scale provides an efficient, psychometrically sound and user-friendly measure of IDSHL in the Chinese population.