Beyond Validation: Lessons From Culturally Adapting the Portuguese Version of the De Jong Gierveld Loneliness Scale

Loneliness is a growing public health priority, particularly among older adults. The De Jong Gierveld Loneliness Scale (DJGLS) is widely used internationally, yet no validated version exists for Portugal. This study aimed to describe the cultural adaptation and content and face validity of the DJGLS for older adults, and highlights key lessons learned regarding the culturally sensitive assessment of loneliness.

Methodological study with three steps: (i) translation and cultural adaptation; (ii) content validity (n = 14 experts); (iii) face validity (n = 10 cognitive interviews). Descriptive and content validity indices were calculated. Interviews were analyzed using content analysis, analyzing item clarity, acceptability, as well as participants' emotional responses and perceptions of the assessment process.

The Portuguese DJGLS demonstrated linguistic equivalence and excellent content validity indices by item (≥ 0.8) and scale (> 0.9). Cognitive interviews supported the scale clarity, acceptability, and comprehensibility. Important semantic, emotional, and ethical considerations were identified as relevant to administering loneliness measures. Some items (such as those referring to emptiness, completely trusting others, or feeling rejected) required clarification or sensitive delivery due to abstract wording, varied interpretations, or emotional vulnerability. These findings highlight the need for careful contextualization, compassionate communication, and awareness of participants' comfort when addressing existential or relational concepts.

The Portuguese version of the DJGLS demonstrated strong content and face validity. Lessons learned underscore the importance of a person-centered and ethically sensitive approach when assessing loneliness in older adults, including providing emotional support during administration and offering information about support services when appropriate.