Relationship between dietary calcium and bone mineral density in school-age children / 中华临床营养杂志

ABSTRACT

Objective To investigate the prevalence of overweight and obesity and the nutritional status of dietary calcium intake in school-age children in Shanghai and to analyze the relationship between dietary calcium and bone mineral density (BMD).Methods A cross-sectional study was conducted in the second and third grade students of 10 primary schools in Yangpu District and Baoshan District in Shanghai. Food frequency questionnaire was used tu estimate the relative intake of dietary calcium of students in 6 primary schools in Baoshnn District. Quantitative ultrasound bone density examination was used to estimate the calcaneal BMD.The relation-ship between calcium intake and BMD was analyzed.Results The average calcium intake was 647 mg/d among ested students.BMD was not significantly different among different age groups (F=1.595,P=0.173),while Z-score was significantly different among different age groups (F=16.02,P=0.000).The total calcium intake was not correlated with BMD or Z-score.The percentage of dairy calcium intake was positively correlated with BMD (r=0.097,P=0.015)and Z-score (r=O.117,P=0.003),the percentage of non-dairy calcium intake and the non-dairy calcium intake were negatively correlated with BMD (r=-0.097,P=0.015) and Z-score(r=-0.110,P=0.006).When the total dietary calcium intake was ≥600 mg/d,BMD and Z-score significantly higherin students with high dairy calcium intake than those with low dairy calcium intake (P<0.05).When the total dietary calcium intake was <600mg/d,BMD and Z-score were higher in students with high dairy calcium in-take than in those with low dairy calcium intake,although no statistical significance was noted (P>0.05).Conclusions BMD and Z-score increase along with the increase of dairy calcium intake.Such effect becomes even more obvious when the total dietary calcium intake is ≥600 mg/d.