Psychometric validation of the Malaysian lifestyle and dietary risk assessment tool for nasopharyngeal cancer (MALDi-NPC)

Nasopharyngeal cancer (NPC) is highly prevalent in Southeast Asia, particularly in Malaysia, where culturally specific lifestyle and dietary exposures contribute significantly to disease risk. Currently, no validated instrument exists to assess these factors within the Malaysian population. This study aimed to develop and validate the Malaysian Lifestyle and Dietary Risk Assessment Tool for Nasopharyngeal Cancer (MALDi-NPC).

The MALDi-NPC was developed through systematic literature review and multidisciplinary expert consultation producing forty-eight items across demographic, lifestyle, and dietary domains. Content validity was assessed for content validity using item-content (I-CVI) and scale-content (S-CVI/Ave) indices by seven experts (five otorhinolaryngologists, one dietitian, one pharmacist). Face validity and pilot testing via item-level (I-FVI) and scale-level (S-FVI/Ave) indices were conducted among 30 NPC patients. Internal consistency was evaluated using Cronbach’s alpha, separately for the lifestyle and dietary domains.

Content validity was excellent (S-CVI/Ave = 0.97), and face validity was high (S-FVI/Ave = 0.98), resulting in a refined thirty-five items instrument. The dietary domain demonstrated acceptable reliability (α = 0.79). The lifestyle domain showed lower internal consistency due to its diverse and conditionally administered items, indicating that each item should be interpreted individually.

The MALDi-NPC is a valid, culturally tailored tool for assessing NPC risk factors in Malaysia. The dietary domain may be used as a reflective construct, whereas the lifestyle domain should be interpreted as a formative construct for individual risk profiling. Further validation in larger, multicentre samples is recommended to strengthen its application in epidemiological research and prevention strategies.