New findings of the thesis: - The thesis has determined the current status of myopia, spinal deformity, and dental caries among primary school students in 6 provinces in 4 regions including the North, Central, South and Central Highlands of Vietnam. The percentage of myopia in primary students was 5.8%, with an upward trend along with grade from 2.9% in grade 1, increased to 8.3% in grade 5; markedly different in different regions and high rate of 10.5% was in Hai Phong, 6.5% in HCM city, a low rate of 0.9% in Kon Tum, 1.1 % in Hoa Binh. Percentage of spinal deformity in students was not high at 3.6%, different by gender (women and men were at 3.0% and 4.1% respectively), increased by grade, different by regions, high in rural and mountainous areas (7.9% in Hoa Binh, 7.1% in Kontum), low in the urbans (2.0% in Ho Chi Minh city, 1.3% in Hai Phong). The percentage of dental caries in primary school students was high at 73.4%, different by gender. This percentage among female students was higher than among male students, tended to decrease with age, there was no significant differences by regions (66.0% - 86.6%). - The thesis has analyzed and pointed out the problems of school health activities, insufficient hygiene conditions along with the lack of knowledge, attitude and practice of students, students’ parents and teachers in the prevention of school-age diseases, contributed to the increasing incidence of the diseases among primary students. The lack of knowledge and wrong practice of students and students’ parents increases the risk of myopia, spinal deformity, and dental caries of students by 1.4 - 2.1 times with the statistical significance p