Development and validation of a sunlight exposure questionnaire for urban adult Filipinos

OBJECTIVES: To develop and validate a self-reported sunlight exposure questionnaire (SEQ) for urban adult Filipinos. METHODS: The study included adults (19-76 years old) in Metro Manila, Philippines, well-versed in the Filipino (Tagalog) language and had resided in Metro Manila for at least 1 year. Exclusion criteria included pregnancy, active skin disorders, and immunocompromised states. An expert panel created a questionnaire in Likert-scale format based on a conceptual framework and 4 existing instruments. The study proceeded in 4 phases: questionnaire item development, translation and back-translation, pretesting, and construct validity and reliability testing using factor analysis, the Cronbach alpha coefficient, and the paired t-test. RESULTS: A 25-item, self-administered, Filipino (Tagalog) SEQ answerable using a 4-point Likert scale was created. The questionnaire was administered to 260 adult participants twice at a 2-week interval, with all participants completing both the first and second rounds of testing. All questionnaire items possessed adequate content validity indices of at least 0.86. After factor analysis, 3 questionnaire domains were identified: intensity of sunlight exposure, factors affecting sunlight exposure, and sun protection practices. Internal consistency was satisfactory for both the overall questionnaire (Cronbach alpha, 0.80) and for each of the domains (Cronbach alpha, 0.74, 0.71, and 0.72, respectively). No statistically significant differences were observed in the responses between the first and second rounds of testing, indicating good test-retest reliability. CONCLUSIONS: We developed a culturally-appropriate SEQ with sufficient content validity, construct validity, and reliability to assess sunlight exposure among urban adult Filipinos in Metro Manila, Philippines.