Development and validation of a scale for "attitudes towards calcium consumption"

Background: Attitude is recognized as a key determinant of health-related behaviors, including calcium intake for prevention of osteoporosis. Most existing instruments that measure attitudes towards calcium consumption are not appropriate for use in the Thai population because they focus on attitudes towards the consumption of dairy products, which are not a common source of calcium for Thais. Objectives: To develop and validate an instrument for measuring attitudes towards calcium consumption among Thai adults. Methods: An initial attitudinal scale (25 items) was developed and administered to 250 Thais (age years) living in Khon Kaen, the largest province in the northeast Thailand, to assess its dimensions using exploratory factor analysis. Three factors were identified. The scale was reduced to 15 items and administered to 733 subjects to validate the identified factor structure and optimize the length of the scale. Results: A three-factor model (10 items) was validated and interpreted as (1) a negative effect of calcium consumption on the body (4 items, reliability = 0.90), (2) the health benefits of calcium consumption for the body (3 items, reliability = 0.78), and (3) the need to take calcium on a regular basis (3 items, reliability = 0.86). The model fitted the data well (relative chi(2) = 1.43, adjusted goodness-of-fit index = 0.98, confirmatory fit index = 0.997, root mean square error of approximation = 0.024). Conclusion: The developed scale is a reliable and useful instrument for measuring attitudes towards calcium consumption. Further research is needed to validate the scale in different populations.