Development and psychometric evaluation of the Khaini Smokeless Tobacco Dependence Scale

Khaini is a smokeless tobacco (SLT) product commonly used in the South-Asian region. It is the most common smokeless tobacco product used in India, having a prevalence of 11.2% and is used by 104.1 million adults. No scales exist to assess khaini dependence. Existing scales available to assess dependence on smokeless tobacco products are not ideal as these are adapted from cigarette dependence scales and developed for western populations. This study aimed to develop a khaini dependence scale and assess its reliability and validity.

Recommended methods for scale development were followed for item development, scale development and scale evaluation. Scale development was guided by a theoretical framework, a review of existing scales and in-depth interviews with 21 khaini users recruited from a tertiary care hospital in Mumbai, India. The process involved the identification of domains for dependence and the development of an item pool. Cognitive interviews and pre-testing were conducted with 20 khaini users to assess content validity. A cross-sectional survey with 323 khaini users was conducted, and Exploratory Factor Analysis (EFA) was used to determine the factor structure of the draft scale. The content validity, criterion validity (by cross-referencing with the cotinine level of users), convergent validity and internal consistency of the new scale were assessed.

The final version of the Khaini SLT Dependence Scale (KSLTDS) had 20 items. EFA indicated an acceptable goodness of fit for a three-factor structure with physical, psychological and sociocultural-behavioral sub-scales. It showed evidence of acceptable criterion validity with cotinine (ρ=0.43, p=0.0002), convergent validity with FTND-ST (ρ=0.51, p<0.0001) and frequency of khaini use (ρ=0.38, p<0.0001). The sub-scales (α=0.87-0.90) showed acceptable internal consistency.

The psychometric evaluation of the KSLTDS showed preliminary validity and reliability for assessing dependence on khaini, and therefore, it is appropriate for clinical and research purposes. Re-validation studies are required with various khaini user populations.