Study On Correlation Between Lifestyle And Bone Mineral Density In Pupil Of Yanji And Okinawa

Objective: Osteoporosis is a serious public health problem worldwide. Bone mineral density in early stage of life is the best indicator for later skeletal condition. This study investigated the correlation between life habit and bone mineral density in pupil, so as to give guidance to improve bone mineral density(BMD), achieve the peak bone mass in early time, and finally prevent osteoporosis in future.Methods: Both 359 healthy Korean Chinese pupil (144 boys and 215 girls) from 3 Korean pupil and 340 Han children (180 boys and 160 girls) from 2 Han pupil in Yanji, China, aged 9-12, were interviewed with the questionnaire of influential factors of bone mineral density in teenagers. The study was also conducted with 342 pupil (164 boys and 178 girls), aged 9-12, from 5 schools in Okinawa, Japan. The items included the generation condition, habit of exercise, sleeping and resting condition, and eating habit. Ultrasound System (AOS-100) was used to determine their calcaneus BMD. The results were statistically analyzed.Results:(1) BMD of the Korean Nationality pupil is higher than Han Nationality. After adjustment of age, BMD in the Korean Nationality pupil is 2.997, Han Nationality is 2.417, Okinawa is 2.451. In the girl, BMD in the Korean Nationality and Kinawa pupil are significantly higher than Han Nationality.(2) Regardless of gender, BMD increased as age, body height and weight increased in pupil (P<0.001). However, age-adjusted results indicated that BMD was only correlated with body weight(P<0.001), not with height.(3) BMD of boys was significantly correlated with milk drinking. Boys who drank milk frequently had higher BMD than those who did not(P<0.05). Although the duration of physical exercise and nationality were not correlated with BMD, the P values were close to 0.05. Boys who exercised more than 1 h a time had higher bone BMD those who exercised less than 1 h. BMD of Korean Chinese boys was higher than those of Han boys(P<0.05).(4) Bone mineral density of girls was significantly correlated with habit of exercise, total activity time per week, snacking habit, ethnicity and menstruation. Girls who regularly did physical exercise had higher BMD than those who seldom do(P<0.05); girls who exercised more than 1 h a week had higher bone mineral density than those who exercised less than 1 h(P<0.01). Girls snacking constantly had higher BMD than those who not(P<0.05). BMD of Korean Chinese girls was higher than that of Han girls(P<0.001), and Okinawan girls also had a higher BMD than Han girls(P<0.001). girls with experience of menstruation had higher BMD than those without. Although the duration of physical exercise, menstruation were not correlated with bone mineral density, the P values were close to 0.05. Girls who exercised more than 1 h a time had higher bone mineral density than those who exercised less than 1 h.(5) Korean Chinese and Han boys who had significant differences in BMD also had significant differences in lifestyle, such as habit of exercise, snacking habit (P<0.05). Although the total activity time per week, regular breakfast skipping, and age of milk drinking were not correlated with bone mineral density, the P values were close to 0.05.(6) Korean Chinese and Han girls who had significant differences in BMD also had significant differences in lifestyle, such as snacking habit, menstruation(P<0.05).(7) Han girls and Okinawa girls who had significant differences in BMD also had significant differences in lifestyle, such as exercise duration, age of milk drinking, and menstruation (P<0.05). Although the regular breakfast skipping were not correlated with bone mineral density, the P values were close to 0.05.Conclusion:1. Regardless of gender, age, height and weight of pupil were positively correlated with BMD. However, age-adjusted results indicated that BMD was only correlated with body weight(P<0.001).2. The major factors that influenced the BMD of pupil were weight,nationality, physical activity, milk drinking, exercise time, snacking habit and menstruation.3. BMD of the Korean Nationality pupil is higher than Han Nationality also had significant differences in lifestyle, such as weight, habit of exercise, snacking habit, menstruation. BMD of the Okinawa girls is higher than Han girls also had significant differences in lifestyle, such as weight, habit of exercise, milk drinking, menstruation.