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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Using existing dietary data for evaluating the construct validity of a nutrient profiling model / Susara JohannaLee

Lee, Susara Johanna January 2013 (has links)
AIM: Nutrient profiling can be defined as ‘the science of categorising foods according to their nutritional composition’ and can be used as a valuable tool in food labelling legislation. Validation is an absolute essential step in the implementation of a nutrient profiling model (NPM), it is important to verify whether or not the NPM has a good solid scientific basis and if it is at all suitable for South Africa. This mini-dissertation investigated the construct validity of a NPM for South Africa. OBJECTIVES: 1) To test construct validity for the nutrient profiling model by examining the relationship between the way the NPM categorises foods and the healthiness of diets in South Africa. 2) To assess if the quality of a diet will improve if ‘unhealthy’ foods are replaced by ‘healthy’ foods as defined by the NPM. STUDY DESIGN: Nested in the South African leg of the international PURE (Prospective Urban and Rural Epidemiology) study at baseline. METHOD: The PURE (Prospective Urban and Rural Epidemiology) baseline study conducted in the North-West province in 2005, was identified as a suitable dataset of food intake. For the first objective the proportion of respondent’s diets consisting of healthy or unhealthy food, as classified by the NPM, was calculated. The respondents were divided into four groups based on their dietary quality as characterised by the Diet Quality Index (DQI), the lower the DQI-score the better the diet quality. The proportion of healthy or unhealthy foods were compared to the DQI-scores using one-way ANOVA’s, p-values were calculated using the Tukey post-hoc test. For the second objective the diet quality of four different diets consisting of either YES foods (according to NPM), NO foods, a combination of YES and NO were calculated and compared. RESULTS: The model displayed good construct validity by showing a statistically significant positive relationship between the proportion of ‘healthy’ (p<0.0001) and ‘unhealthy’ (p<0.0001) foods, as classified by the NPM, and participants’ DQI-scores. The second objective was also confirmed and a diet consisting of ‘healthy’ foods or a diet where ‘unhealthy’ foods were substituted by ‘healthy’ foods, had a better DQI than diets consisting only of ‘unhealthy’ foods CONCLUSION: Construct validity was confirmed by proving that the better the diet quality of the respondents the bigger their proportion of foods categorised as ‘healthy’ by the NPM and vice versa. / MSc (Dietetics), North-West University, Potchefstroom Campus, 2014
2

Using existing dietary data for evaluating the construct validity of a nutrient profiling model / Susara JohannaLee

Lee, Susara Johanna January 2013 (has links)
AIM: Nutrient profiling can be defined as ‘the science of categorising foods according to their nutritional composition’ and can be used as a valuable tool in food labelling legislation. Validation is an absolute essential step in the implementation of a nutrient profiling model (NPM), it is important to verify whether or not the NPM has a good solid scientific basis and if it is at all suitable for South Africa. This mini-dissertation investigated the construct validity of a NPM for South Africa. OBJECTIVES: 1) To test construct validity for the nutrient profiling model by examining the relationship between the way the NPM categorises foods and the healthiness of diets in South Africa. 2) To assess if the quality of a diet will improve if ‘unhealthy’ foods are replaced by ‘healthy’ foods as defined by the NPM. STUDY DESIGN: Nested in the South African leg of the international PURE (Prospective Urban and Rural Epidemiology) study at baseline. METHOD: The PURE (Prospective Urban and Rural Epidemiology) baseline study conducted in the North-West province in 2005, was identified as a suitable dataset of food intake. For the first objective the proportion of respondent’s diets consisting of healthy or unhealthy food, as classified by the NPM, was calculated. The respondents were divided into four groups based on their dietary quality as characterised by the Diet Quality Index (DQI), the lower the DQI-score the better the diet quality. The proportion of healthy or unhealthy foods were compared to the DQI-scores using one-way ANOVA’s, p-values were calculated using the Tukey post-hoc test. For the second objective the diet quality of four different diets consisting of either YES foods (according to NPM), NO foods, a combination of YES and NO were calculated and compared. RESULTS: The model displayed good construct validity by showing a statistically significant positive relationship between the proportion of ‘healthy’ (p<0.0001) and ‘unhealthy’ (p<0.0001) foods, as classified by the NPM, and participants’ DQI-scores. The second objective was also confirmed and a diet consisting of ‘healthy’ foods or a diet where ‘unhealthy’ foods were substituted by ‘healthy’ foods, had a better DQI than diets consisting only of ‘unhealthy’ foods CONCLUSION: Construct validity was confirmed by proving that the better the diet quality of the respondents the bigger their proportion of foods categorised as ‘healthy’ by the NPM and vice versa. / MSc (Dietetics), North-West University, Potchefstroom Campus, 2014
3

The validation of a suitable nutrient profiling model for South Africa / Mariaan Wicks.

Wicks, Mariaan January 2012 (has links)
Aim Nutrient profiling is defined as “the science of classifying or ranking food items according to their nutritional composition for reasons related to preventing disease and promoting health, and can be used to govern the criteria under which nutrient and/or health claims may be made”. The validation of a nutrient profiling model (NPM) is an essential part of the model development process, and is extremely important for the model to meet basic scientific criteria. This mini-dissertation investigated the content and convergent validity of a suitable NPM for South Africa. Method Content validity was tested for by comparing the NPM classification of 131 “indicator” foods with the classification of the “indicator” foods by the Food Based Dietary Guidelines (FBDGs). Convergent validity was tested for by comparing the standard ranking of a representative data set of food items (n = 128) by nutrition experts with the classification of the food items by the NPM. The questionnaire asked respondents to rank 40 foods (electronically generated from a master list of 128 foods) according to the nutritional information provided from “more healthy” to “less healthy” using a six point Likert scale. The 128 foods were selected to be representative of the South African diet. These questionnaires were sent via e-mail to all full members (n = 1105) of the Association of Dietetics in South Africa. The draft “Guiding principles and framework manual for the development or adaptation of nutrient profile models” dated 22 February 2011 (WHO, 2011), was used as a guide in the validation process of the NPM. Results The NPM showed good content validity: the way that the NPM categorises foods correspond well with that of the FBDGs (kappa statistic = 0.73). Two hundred and ninety two responses were received (26.4%) from the nutrition experts, these responses were used to rank the 128 foods by the average score which they received from the nutrition experts. The NPM also showed good convergent validity: the NPM classification of foods had a good correlation with the standard ranking of foods by dietitians (r = 0.853; p = 0.0001). Conclusion The NPM demonstrated good content validity by classifying food items in way that supports the FBDGs with the exception of a few processed food items and combined food items. The NPM also demonstrated good convergent validity by classifying food items in accordance with the views of nutrition experts in South Africa. / Thesis (MSc (Dietetics))--North-West University, Potchefstroom Campus, 2013.
4

The validation of a suitable nutrient profiling model for South Africa / Mariaan Wicks.

Wicks, Mariaan January 2012 (has links)
Aim Nutrient profiling is defined as “the science of classifying or ranking food items according to their nutritional composition for reasons related to preventing disease and promoting health, and can be used to govern the criteria under which nutrient and/or health claims may be made”. The validation of a nutrient profiling model (NPM) is an essential part of the model development process, and is extremely important for the model to meet basic scientific criteria. This mini-dissertation investigated the content and convergent validity of a suitable NPM for South Africa. Method Content validity was tested for by comparing the NPM classification of 131 “indicator” foods with the classification of the “indicator” foods by the Food Based Dietary Guidelines (FBDGs). Convergent validity was tested for by comparing the standard ranking of a representative data set of food items (n = 128) by nutrition experts with the classification of the food items by the NPM. The questionnaire asked respondents to rank 40 foods (electronically generated from a master list of 128 foods) according to the nutritional information provided from “more healthy” to “less healthy” using a six point Likert scale. The 128 foods were selected to be representative of the South African diet. These questionnaires were sent via e-mail to all full members (n = 1105) of the Association of Dietetics in South Africa. The draft “Guiding principles and framework manual for the development or adaptation of nutrient profile models” dated 22 February 2011 (WHO, 2011), was used as a guide in the validation process of the NPM. Results The NPM showed good content validity: the way that the NPM categorises foods correspond well with that of the FBDGs (kappa statistic = 0.73). Two hundred and ninety two responses were received (26.4%) from the nutrition experts, these responses were used to rank the 128 foods by the average score which they received from the nutrition experts. The NPM also showed good convergent validity: the NPM classification of foods had a good correlation with the standard ranking of foods by dietitians (r = 0.853; p = 0.0001). Conclusion The NPM demonstrated good content validity by classifying food items in way that supports the FBDGs with the exception of a few processed food items and combined food items. The NPM also demonstrated good convergent validity by classifying food items in accordance with the views of nutrition experts in South Africa. / Thesis (MSc (Dietetics))--North-West University, Potchefstroom Campus, 2013.

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