Dietary supplements (DS) are an important source of nutrients for large segments of the US population. DS use has been monitored in NHANES since the early 1970's using the Dietary Supplement Questionnaire (DSQ). The DSQ captures supplement use over the last 30 days. In NHANES 2007–8, DS information was collected using both the DSQ and as part of two, 24-hour dietary recalls (24HR). Thus, for the first time, data on supplement use are provided using 2 different methods that capture intake over two different time periods: the prior day, and the past month. We analyzed DS data on participants > 1 y (n=7,405). Crombach's α (CA) was used to determine agreement between the 2, 24HR and the DSQ, CA can be interpreted like a correlation coefficient. Prevalence of any DS use had good agreement between the DSQ (46%) and 24HR day 1 (36%) and day 2 (38%) (CA =0.87) but did vary in age groups (lowest agreement in 1–3 y olds). Prevalence of use of calcium (CA =0.91 ), folic acid (CA=0.88) and vitamin D (CA = 0.88) exhibited high agreement. Agreement in the mean intakes of these nutrients were also assessed: calcium (CA = 0.88), folic acid (CA=0.82), and vitamin D (CA=0.50). How best to use the DSQ in conjunction with the 24HR data to accurately to produce total nutrient intakes for answering research questions will be described and recommendations will be addressed.
No takes yet. Share an insight, caveat, or question.
Bailey et al. (2011) studied this question.