Background Dehydration among school children is highly prevalent. It has various negative
health consequences in children, and it impairs cognitive performance. The figures of
hydration status among Egyptian school children are scarce. Objectives: 1) Assess the
prevalence of dehydration among school children. 2) Identify the effect of students' hydration
status on cognitive function. 3) Determine the impact of health education on the students'
drinking behavior, hydration status and cognitive abilities. Method: Pretest-posttest
intervention study included (n=180) students. Urine osmolality was tested to the students.
Seven cognitive function tests were conducted measuring (visual attention, visual memory,
short term memory, mathematical cognition and visuomotor skills). Providing drinking water
education to the students then reassessment of urine osmolality and reapplying cognitive
function tests. Results: Sixty eight percent of the students were dehydrated and was
significantly decreased after health education to reach 47.8%. The hydrated students
performed significantly better than dehydrated in cognitive function tests except for reverse
number recall and mathematical cognition where the improvement was shown to be
significant. Urine osmolality was significantly negatively correlated with mean scores of
cognitive function tests of (visual attention, forward number recall and line tracing). There
was significant improvement in the cognitive function test after health education for letter
cancelation, visual memory, forward number recall and mathematical cognition.
Conclusions: Dehydration in highly prevalent among school children and have negative
impact on cognitive performance. Health education to the students helped in improving
drinking behavior and adopting healthy drinking water practices. Schools are encouraged to
implement drinking water polices and rules.