Daily caffeine intake among Osijek High School students: questionnaire study.

AIM: To assess caffeine intake habits of Osijek high school students and identify the most important sources of caffeine intake. METHODS: Adjusted Wisconsin University Caffeine Consumption Questionnaire was administered to 571 high school students (371 boys and 200 girls in the ninth grade) from Osijek, the largest town in eastern Croatia. The level of caffeine in soft drinks was determined by the high pressure liquid chromatography method, and in chocolate and coffee from the literature data. RESULTS: Only 10% of our participants did not use foodstuffs containing caffeine. The intake of caffeine originated from soft drinks (50%), coffee (37%), and chocolate (13%). The mean caffeine concentration in soft drinks was 100-/+26.9 mg/L. The mean estimated caffeine intake was 62.8-/+59.8 mg/day. There was no statistically significant difference between boys and girls in caffeine consumption (1.0-/+0.9 mg/kg bw for boys vs 1.1-/+1.4 mg/kg bw for girls). Daily caffeine intake of 50-100 mg was recorded in 32% of girls and 29% of boys, whereas intake greater than 100 mg/day was recorded in 18% of girls and 25% of boys. CONCLUSION: Soft drinks containing caffeine were the major source of caffeine intake in high school students. Large-scale public health measures are needed to inform the public on health issues related to excessive intake of caffeine-containing foodstuffs by children and adolescents.