The Use of Combined Oral Contraceptives for ˃6 Months Is Not Associated with Body Fat or Bone Density, Regardless of Dietary Differences—A Pilot Study

<i>Background and Objectives</i>: There is a lack of information on the dietary intake of long-term combined oral contraceptive users (COC-users) in relation to their body composition. The aim of the pilot study was to determine the food consumption of young women using COCs for >6 months and its relationship to body composition compared to non-users. <i>Materials and Methods</i>: A total of 45 healthy women (21.8 ± 1.7 years) were divided into COC non-users (<i>n</i> = 19) and users of a low (≤20 μg) ethinylestradiol (EE) dose (<i>n</i> = 18) and a medium (30-35 μg) EE dose (<i>n</i> = 8). Anthropometric data, body composition, physical activity levels, three-consecutive-days of dietary records, and serum concentrations of calcium, magnesium, and vitamin D were assessed. Statistical methods included chi-squared, Fisher's exact test, <i>t</i>-test, Mann-Whitney U test, Spearman's correlation, and multiple linear regression. <i>Results</i>: There were no differences between COC-users and non-users in terms of physical activity, intake of micronutrients, body mass index, body fat percentage (BF%), or bone mineral density (BMD). COC-users consumed a higher percentage of energy from fats (<i>p</i> = 0.02) and had higher serum vitamin D levels (<i>p</i> < 0.01). BF% was negatively associated with BMD (coefficient -0.008; <i>p</i> = 0.027). <i>Conclusions</i>: The use of COCs for ˃6 months is not associated with FM or BMD, regardless of dietary differences. Further attention should be paid to possible associations between COCs use, dietary habits, and body composition (including BMD).