Hydration status of Arabic adolescents and young men: Measurement, evaluation, and a school-based initiative to improve drinking behavior

Background: Despite the importance of hydration, limited research on the topic has been undertaken in Arabic populations. Methods: Study 1. Five sequential daily midmorning urine samples were provided by 88 adult military cadets and 32 school-based adolescents. Hydration thresholds were produced using percentiles of estimated urine osmolality (U_osm) and urine color (U_col). Study 2. The authors assessed 1,077 midmorning urine samples from 120 military cadets and 52 adolescents for the U_osm:U _col relationship using regression. Study 3. The authors conducted a 4-wk hydration campaign in which 21 adolescents participated, providing urine samples before (PreC), at the end of (EndC), and 2 wk after the campaign (PostC). Results: Study 1. Euhydration (41-60th percentile) was 881-970 mOsmol/kg in adults and 821-900 mOsmol/kg in adolescents. Study 2. In both cohorts, U_osm and U_col were associated (p < .01): adults R² = .33, adolescents R² = .59. Study 3. Urine osmolality was significantly higher PreC than at EndC and PostC. Conclusions: Urinary output of Arabic adolescents and military cadets was more concentrated than frequently recommended for euhydration. Further work in similar populations is required to determine if these values represent hypohydration or merely reflect dietary and cultural differences. In male Arabic adolescents and adults, U_col was an adequate indicator of hydration status. Favorable hydration changes were made after a school-based health campaign.