卫生研究

目的评价即时性图像法膳食调查技术在城市孕妇人群膳食评估中的有效性和可行性。方法招募61名住院保胎孕妇,为其提供一次经严格称重后烹制的午餐,运用即时性图像法膳食调查技术,评估每位孕妇的膳食量,并与传统24 h回顾法进行比较。其中食物称重、膳食图像估量、24 h膳食回顾调查三个环节工作分别由三组不同的调查员完成,各环节间信息相互隔离。将图像法估计数据和24 h回顾数据分别与膳食称重数据进行相关性分析,并基于不同膳食评估数据计算能量和营养素供应量,比较不同方法所获数据的差异。最后就图像法和称重法进行方法一致性检验,结合问卷调查定性指标综合评价图像法的可行性和研究效率。结果实验餐膳食共涉及粮谷类、蔬菜、豆制品、鱼类、肉类共23种食物。图像法估量数据与实际量的相关性(r=0.778,P<0.05,n=308)比24 h回顾(r=0.413,P<0.05)更好,分布更集中于线性趋势;从两组数据与实际量的差值绝对值分布来看,图像法为17.51±14.27,24 h回顾法为36.20±36.25(P<0.05,n=308),从两种方法计算得到的能量值与实际能量供给的差值绝对值分布看,图像法为77.23±56.02,24h回顾法为172.77±115.18(P<0.05,n=61),图像法与实际能量供给更接近,分布更集中。Bland-Altman检验发现即时性图像法与称重法一致性良好,差值均数和0逼近,绝大数散点都分布在x珋±1.96s内。问卷调查统计结果显示,56名孕妇认为图像法负担更小,耗时更少;58名孕妇表示愿意通过图像法了解自己的膳食状况。结论即时性图像法膳食调查技术在参与调查的城市孕妇中依从性更好,可靠性更高,与称重法一致性良好。

Objective To evaluate the usefulness and efficiency of a novel dietary method among urban pregnant women. Methods Sixty one pregnant women were recruited from the ward and provided with a meal accurately weighed before cooking. The meal was photographed from three different angles before and after eating. The subjectswere also interviewed for 24 h dietary recall by the investigators. Food weighting,image quantification and 24 h dietary recall were conducted by investigators from three different groups,and the messages were isolated from each other. Food consumption was analyzed on bases of classification and total summation. Nutrient intake from the meal was calculated for each subject. The data obtained from the dietary recall and the image quantification were compared with the actual values. Correlation and regression analyses were carried out on values between weight method and image quantification as well as dietary recall. Results Total twenty three kinds of food including rice,vegetables,fish,meats and soy bean curd were included in the experimental meal for the study. Compared with data from 24 h dietary recall( r = 0. 413,P < 0. 05),food weight estimated by image quantification( r = 0. 778,P < 0. 05,n = 308) were more correlated with weighed data,and show more concentrated linear distribution. Absolute difference distribution between image quantification and weight method of all food was 77. 23 ± 56. 02( P < 0. 05,n =61),which was much small than the difference( 172. 77 ± 115. 18) between 24 h recall and weight method. Values of almost all nutrients, including energy, protein, fat,carbohydrate,vitamin A,vitamin C,calcium,iron and zinc calculated based on food weight from image quantification were more close to those of weighed data compared with24 h dietary recall( P < 0. 01). The results found by the Bland Altman analysis showed that the majority of the measurements for nutrient intake,were scattered along the mean difference line and close to the equality line( difference = 0). The plots show fairly good agreement between estimated and actual food consumption. It indicate that the differences( including the outliers) were random and did not exhibit any systematic bias,being consistent over different levels of mean food amount. On the other hand,the questionnaire showed that fifty six pregnant women considered the image quantification was less timeconsuming and burdened than 24 h recall. Fifty eight of them would like to use image quantification to know their dietary status. Conclusion The novel method which called instant photography( image quantification) for dietary assessment is more effective than conventional 24 h dietary recall and it also can obtain food intake values close to weighed data.