Background/objectives: Vitamin/mineral (VMS) and dietary supplements (DS) use is common in Switzerland, but nothing is known regarding the factors associated with their initiation, discontinuation or continuation of intake.
Subjects/methods: Prospective study conducted between 2003-2006 and 2009-2012 in Lausanne, Switzerland among 4676 participants (2525 women, age range 35-75 years). VMS were defined as single or multivitamin/multimineral preparations; DS were defined as any dietary supplement.
Results: VMS use was 20.6% at baseline and 20.3% at follow-up (P=0.69): 559 (12.0%) participants discontinued; 545 (11.7%) initiated and 404 (8.6%) continued VMS use. On multivariable analysis, men had a lower relative risk ratio (RRR) of discontinuing, initiation or continuing; older age and being physically active were associated with a higher RRR of initiation or continuing; lower education and higher body mass index were associated with a lower RRR of discontinuing or continuing of VMS. DS use decreased from 10.4 to 6.8% (P<0.001): 405 (8.7%) participants discontinued; 239 (5.1%) initiated and 81 (1.7%) continued DS use. On multivariable analysis, men had a lower RRR of discontinuing, initiation or continuing; older age had a higher RRR of initiation, discontinuing or continuing; being physically active was associated with a higher RRR of initiation or continuing; Swiss citizens and former smokers had a higher RRR of discontinuing.
Conclusions: VMS use is stable in the Lausanne population, whereas DS use appears to be decreasing. Individuals can be categorized either as users or non-users depending on the study period, and consistent users are only a small fraction of prevalent users.