Differences in sociodemographic, lifestyle, and dietary characteristics between dietary supplement users and non-users: a cross-sectional study among three generations of Japanese women

We examined differences in characteristics between dietary supplement (DS) users and non-users in three age groups of Japanese women, including younger women (dietetic students), middle-aged women (their mothers), and older women (their grandmothers). In total, 3952 younger women (aged 18 years), 3780 middle-aged women (aged 34-60 years), and 2192 older women (aged 61-94 years) participated in this cross-sectional study in 2011 and 2012. DS use and other characteristics were self-reported using a questionnaire, and dietary intake from foods was assessed using a validated, self-administered diet history questionnaire. DS users were defined as participants who reported using DS at least once in the past month. We calculated the percentage of participants with nutrient intakes below the Estimated Average Requirement (EAR) from the Japanese Dietary Reference Intakes. The proportion of DS users was 5.7% in younger women, 24.3% in middle-aged women, and 27.7% in older women. In younger and older women, DS users were more likely to live in a city with a population of ≥ 1 million. In middle-aged women, DS users were more likely to have an education level more than high school or to be former smokers. In older women, DS users tended to have shorter sleep duration. Among the 15 nutrients examined, DS users were less likely to have intake levels below the EAR for 10 nutrients in younger women, 9 nutrients in middle-aged women, and 4 nutrients in older women. Some characteristics of Japanese female DS users differed from non-users depending on the age group.