学龄期儿童膳食钙与骨密度的关系

目的 调查上海地区学龄期儿童膳食钙摄入现状及骨营养状况,分析膳食钙与骨密度(BMD)的关系.方法 以上海市杨浦区和宝山区10所小学二、三年级学生为研究对象,每个年级随机 抽取2个班级进行定量超声BMD测量,对宝山区6所小学所有二、三年级学生采用食物频率问卷法进行钙摄入量调查,分析调查人群膳食钙与BMD关系.结果 受试儿童平均钙摄入量为647 mg/d.不同年龄别BMD间差异无统计学意义(F=1.595,P=0.173),但不同年龄别间BMD的Z值差异有统计学意义(F16.02,P=0.000).总钙摄入量与BMD及其Z值无关.乳钙占总钙的百分比与BMD及其Z值均呈显著正相关(r=0.097,P=0.015;r=0.117,P=0.003),非乳钙占总钙的百分比和非乳钙摄入量与BMD及其Z值均呈显著负相关(r=-0.097,P=0.015;r=-0.110,P=0.006).当总钙摄入量≥600mg/d时,高乳钙组的BMD及其z值明显高于低乳钙组(P<0.05).当总钙摄入量<600mg/d时,高乳钙组的BMD及其Z值较低乳钙组虽有升高趋势,但差异无统计学意义(P>0.05).结论 高乳钙摄入对BMD有促进作用,当总钙摄入量≥600 mg/d时,该作用明显增强.

Relationship between dietary calcium and bone mineral density in school-age children

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.