The demographic data of the participants are shown in Table 1.
Validity and reliability the instruments
Following the Delphi round, expert ideas was reasonably uniform. All items in both questionnaires remained because of the criterion of I-CVI>0.78. The average CVI of the knowledge and Attitude Questionnaire was equal to 0.749 and 0.946, respectively and CVR was equal to 0.801 and 0.917, respectively.
Concerning construct validity, the results of KMO test (0.78 for knowledge questionnaire and 0.92 for attitude questionnaire) more than the recommended index of 0.60 (25) and Bartlett’s test of sphericity (p-value <0.05) indicate the adequacy of sample size for performing factor analysis on both knowledge and Attitude questionnaires. All questions in the questionnaires were subject to selection criteria. Viramax rotation was used for factor analysis. The result showed that the knowledge questionnaire had eight factors: factor 1, including items 1, 2, 6, 7, 8, 10, 11 and 12, entitled “Lipid knowledge”, factor 2, including items 13, 19, 20, 21, 46, 47, 48, 49, 50 and 51, related to “nutrition in stress and cancer”, factor 3, including items 3, 14, 30, 31, 32, 33, 34 and 35, related to “nutrition in cardiovascular diseases”, factor 4, including items 15, 16, 17 and 18, related to “weight management”, factor 5, including items 5, 22, 23, 24, 25, 26, 27, 28 and 29, related to “nutrition in gastrointestinal diseases”, factor 6, including items 36, 37, 38 and 39, related to “nutrition in diabetes” and finally factor 7, including items 4, 9, 40, 41, 42, 43, 44 and 45, related to “nutrition renal diseases”. The range of unrotated factor loading in the nutritional knowledge questionnaire was 0.59 to 0.91 (all>0.45). Accordingly, the attitude questionnaire had four factors. The range of unrotated factor loading in the attitude questionnaire was 0.65 to 0.95 (all>0.45).
The internal consistency of the knowledge and attitude tool was calculated using Cronbach's alpha, which for the knowledge and attitude questionnaires were 0.703 and 0.816 (0.765 for question 1-22 and 0.726 for questions 23-29) respectively, with the satisfactory value being 0.70–0.95 (26).
Regarding the reliability evaluation of the knowledge and attitude questionnaire, the correlation coefficient of the knowledge questionnaire was 0.81 in the range of 0.68-0.93. The correlation coefficient of the attitude questionnaire was 0.80 in the range of 0.67-0.94, indicating the reliability of the tool.
The comparison of correct knowledge, perceived knowledge and accuracy of knowledge of participants is shown separately in Table 2. Most students had a weak correct nutrition knowledge (<68%), with a frequency of 116 (52.3%). Eighty precipitants (36.0%) had average (68-76%), 18 person (8.1%) had good (77-83%) and 6 persons had good (>83%) correct nutrition knowledge. The relationship between demographic characteristics such as sex and also training course (extern vs. intern) with nutritional knowledge of respondents is shown as Table 3.
The most knowledge was in the field of general nutrition with true answer in 86.69 ± 13.44 percent of participants and the lowest knowledge in the field of fats with true answer in 53.55 ± 13.95 percent of participants. Other topics were between these. Also, there was a significant difference between two groups in comparison of nutritional knowledge indices and different domains of nutritional knowledge between externs and interns in dietary fiber (P <0.001), but in other areas there was no significant difference (P>0.05).
The comparison of the attitude index in externs and interns is shown separately in Table 2. Comparing students' attitudes towards nutrition, most students had a very favorable attitude (≥88), with a frequency of 204 (92.7%). Fifteen precipitants (6.8%) had desirable (59-87) and 1 person (0.5%) had undesirable (≤58) attitude. The relationship between demographic characteristics such as sex and also training course (extern vs. intern) with nutritional attitude of respondents is shown as Table 3.
There was not significant relationship between nutritional knowledge and attitude toward among participants (p=0.066).