Prevalence of dietary supplement use and associated factors among fitness center users in Madrid, Spain

Abstract

Consumption of supplements is common among fitness center users worldwide, including in Spain. The aim of this study was to evaluate the association between dietary supplement use and associated factors (demographic and sports practice) among fitness center users from Madrid, Spain. A cross-sectional study was carried out with users of fitness centers in Madrid, Spain. An online questionnaire was used, containing questions about demographic data, physical exercise, and consumption of dietary supplements. Data were analyzed using Student's t-test for continuous variables and Fisher's exact or χ-square test for categorical variables. The significance level used was p<0.05. Of the 179 individuals evaluated, 39.7% consumed supplements, which was more reported by younger individuals (p=0.024), by men (p<0.001), and by self-prescribed (45.1%). The consumption of supplements was associated with longer weekly training time (382.39± 203.0; p<0.001), higher weekly frequency (>5 times; p=0.038), and the practice of combined exercise (51.4%; p<0.001). Most men used more than 3 supplements (p<0.001) for more than one year (52.1%; p<0.001). Both genders also reported gaining muscle mass (24.6%) as the main motivation for using supplements. In conclusion, supplement consumption was higher among men, younger individuals, and self-prescribed. Consumption was also related to the reason for gaining muscle mass, the practice of anaerobic+aerobic exercises, and greater weekly training time and frequency.