Use of dietary supplements in Denmark is associated with health and former smoking

Abstract

Objectives:To describe the use of dietary supplements in a group of Danish adults and to investigate the differences between users and non-users with respect to age, gender, health and lifestyle factors.Design:Cross-sectional study in two Danish cities.Setting:The Danish Investigation on Iodine Intake and Thyroid Diseases, 1997–1998.Subjects:Participants were 3707 women (selected age groups between 18 and 65 years) and 942 men (60–65 years). Participation rate was 50%. Supplement data were collected in a personal interview. Data on education, smoking, alcohol intake, physical activity, use of medication and self-perceived health were derived from a self-administered questionnaire. Multiple logistic regression was used for the statistical analysis.Results:Participants were asked about all kinds of supplements, ranging from products containing vitamins and minerals, to fish oils and products of herbal origin. On average 59% reported use of some kind of dietary supplement. Most common were combined multivitamin/mineral products (48%) followed by single vitamin C products (10%). Twelve per cent used three or more different supplements. Supplement use was strongly associated with age and gender, being highest among elderly women (78%). Ex-smokers were more likely to use supplements than subjects who had never smoked (odds ratio (OR) 1.36, 95% confidence interval (CI) 1.09–1.76). Supplement use was more likely among subjects who had many days of illness (OR = 1.37, 95% CI 1.12–1.66) and among users of medication (OR = 1.22, 95% CI 1.04–1.42). Subjects who perceived their health as poor were more likely to use supplements other than just a multivitamin/mineral tablet (OR = 2.2, 95% CI 1.31–3.77).Conclusions:Use of dietary supplements was related to age, gender and smoking, but also to poor self-perceived health status and absence from work. This indicates that a group of people use supplements as a form of self-medication.