Exploring Factors Associated with Health Status and Dietary Supplement Use Among Portuguese Adults: A Cross-Sectional Online Survey

<b>Background/Objectives</b>: Dietary supplements are associated with general well-being. However, there is a growing concern about health risks from unlabeled harmful substances, contaminants, or their interactions with conventional drugs. The use of dietary supplements should also be monitored in vulnerable groups. Hence, this study aimed to explore key factors associated with dietary supplement use and health status among Portuguese adults. <b>Methods</b>: An online-based cross-sectional survey was conducted to assess health, medication, and dietary supplement use. Data were collected from January to February 2023. The participants (N = 449) were categorized into age groups (18-29, 30-39, 40-60, and 60+). Descriptive and multivariate statistical analysis were performed. <b>Results</b>: Overall, 73% of the participants were female, with 38% in the 40-60 age group. Among male participants (27%), more than half belonged to the two older age groups. Additionally, 42% reported having a diagnosed disease, 43% reported using medication, and 66% rated their health as "good". Participants aged 60+ with multiple diagnosed diseases and a higher BMI were associated with poorer self-rated health. Cardiovascular drug use was more prevalent among males and the 60+ age group, positively correlating with the number of medications (r = 0.40, <i>p</i> < 0.001). Medication use (OR = 0.25, 95%CI: 0.10-0.60) and diagnosed diseases (OR = 0.34, 95%CI: 0.17-0.69) were associated with a lower likelihood of avoiding supplement use. Females were more likely to use supplements, with multivitamin-mineral supplements most common among both sexes and adults aged 60+. <b>Conclusions</b>: As supplement use increases, developing evidence-based guidelines for safe use, especially among vulnerable populations, is crucial.