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Background: The use of new technology has the potential to increase participation rates in dietary studies and improve the validity of collected dietary data. However, to evaluate the usability of developed dietary methods, qualitative studies of participants’ experiences and perceptions are needed.

Objective: To explore adolescents’ experiences using a newly developed mobile phone dietary assessment app, with a focus on factors that could affect their recording of dietary intake.

Methods: Focus group interviews were conducted with 75 participants who had used a newly developed mobile phone dietary assessment app in a quantitative evaluation study. The interviews were analyzed using qualitative content analysis and the theoretical framework of Self Determination Theory was applied.

Results: The adolescents’ use of the mobile phone dietary assessment app was characterized by their struggle to overcome several perceived barriers. Facilitators that helped adolescents complete the method were also identified. Motivation was found to be an important facilitator, and intrinsically motivated participants completed the method because they found it fun to use. The autonomous extrinsically motivated participants completed the method for the greater good, in order to contribute to the study. The controlled extrinsically motivated participants completed the method to get a reward or avoid punishment. Amotivated participants did not complete the method. More motivated participants were assumed to be more able to overcome barriers and needed less facilitators.

Conclusions: Future studies that examine the recording of food intake should include systematic efforts that aim to minimize identified barriers and promote identified facilitators. Further research should specifically aim at studying methods for (and effects of) increasing intrinsic motivation by supporting autonomy, competence, and relatedness among adolescents asked to participate in dietary studies.

Background: There is a great need for dietary assessment methods that suit the adolescent lifestyle and give valid intake data. Objective: To develop a mobile phone app and evaluate its ability to assess energy intake (EI) and total energy expenditure (TEE) compared with objectively measured TEE. Furthermore, to investigate the impact of factors on reporting accuracy of EI, and to compare dietary intake with a Web-based method. Methods: Participants 14 to 16 years of age were recruited from year nine in schools in Gothenburg, Sweden. In total, 81 adolescents used the mobile phone app over 1 to 6 days. TEE was measured with the SenseWear Armband (SWA) during the same or proximate days. Individual factors were assessed with a questionnaire. A total of 15 participants also recorded dietary intake using a Web-based method. Results: The mobile phone app underestimated EI by 29% on a group level (P<.001) compared to TEE measured with the SWA, and there was no significant correlation between EI and TEE. Accuracy of EI relative to TEE increased with a weekend day in the record (P=.007) and lower BMI z-score (P=.001). TEE assessed with the mobile phone app was 1.19 times the value of TEE measured by the SWA on a group level (P<.001), and the correlation between the methods was .75 (P<.001). Analysis of physical activity levels (PAL) from the mobile phone app stratified by gender showed that accuracy of the mobile phone app was higher among boys. EI, nutrients, and food groups assessed with the mobile phone app and Web-based method among 15 participants were not significantly different and several were significantly correlated, but strong conclusions cannot be drawn due to the low number of participants. Conclusions: By using a mobile phone dietary assessment app, on average 71% of adolescents' EI was captured. The accuracy of reported dietary intake was higher with lower BMI z-score and if a weekend day was included in the record. The daily question in the mobile phone app about physical activity could accurately rank the participants' TEE.

Abstract

Background There is a great need for improved dietary assessment methods that give valid intake data and are more user friendly than traditional methods.

Objectives The aim of this thesis was to develop, implement, and evaluate dietary assessment methods using new approaches and technologies in young populations, and to investigate variables that are important for reporting accuracy. Another aim was to investigate day-of-the-week effects on assessed energy and sugar intakes among children and adolescents.

Methods This thesis is based on data collected as part of four different studies on the implementation of the following dietary assessment methods: the short dietary questionnaire (SDQ), a food record (FR) with either a digital camera or smartphone, and a computer-based 24-hour recall. Young pregnant and non-pregnant women with different weight statuses completed the SDQ. Children with overweight and obesity used digital cameras to complete FRs, and adolescents used the smartphone application FR. Parents of 2‒9-year-old European children completed the computer-based 24-hour recall and the results of sugar intake of the children on weekdays and weekends were analysed. The SDQ was evaluated against doubly labelled water (DLW) and a more extensive food frequency questionnaire (FFQ). The two FRs were evaluated against data from a SenseWear Armband (SWA), and the smartphone FR was further compared to a web-based FR.

Results The new approaches and technologies used in the dietary assessment methods in this thesis captured between 70% and 79% of the energy intake (EI) of children, adolescents and young women, and the ranking according to EI was generally low with all methods. The negative effect on reporting accuracy with increasing BMI/weight status that has been observed previously was confirmed in our studies. In children and adolescents, a weekend day in the FR emerged as a factor that was positively associated with reporting accuracy. Assessed sugar intake in children and adolescents was high in general and highest on weekends, although EI did not differ between weekdays and weekends.

Conclusions FRs using technology should focus on simplifying the recording of consumed foods and amounts to a greater extent, for example, by automatizing these steps as much as possible. The SDQ could be further adapted for testing among other groups than young women, and could be adapted for specific objectives. Factors influencing reporting accuracy need to be taken into consideration and further explored when assessing dietary intake. In order to make it possible to evaluate sugar intake in relation to nutritional recommendations, information about added sugar in foods needs to be incorporated into food composition databases. Further development and research is needed to obtain dietary assessment methods with improved accuracy and user friendliness.

Sammanfattning

Bakgrund Traditionella kostundersökningsmetoder är krävande och har flera felkällor, vilket ofta leder till att energiintaget (EI) från insamlade kostdata är lägre än individens uppmätta totala energiförbrukning (TEE). Det finns ett stort behov av kostundersökningsmetoder som ger valida resultat och är användarvänliga.

Syfte Syftet med avhandlingen var att vidareutveckla kostundersökningsmetoder och att im plementera och utvärdera dem bland barn, ungdomar och unga kvinnor. Syftet var också att undersöka faktorer med betydelse för en korrekt rapportering av kostintaget. Vidare var syftet att undersöka skillnader i EI och intag av socker under vardagar och helger bland barn och ungdomar.

Metod Avhandlingen baseras på data från fyra olika studier där olika nyutvecklade kostundersökningsmetoder användes. I en studie användes en kort kostenkät (SDQ) på unga gravida och icke-gravida kvinnor med olika viktstatus. Rapporterat EI jämförde s med TEE uppmätt med dubbelmärkt vatten-metoden, och rapporterat intag av näringsämnen och livsmedel jämfördes med en mer omfattande kostenkät (FFQ). I en annan studie samlades kostdata in för 2 ‒ 9-åringar från åtta europeiska länder med hjälp av en datoriserad 24-timmars recall som besvarades av föräldrarna. Barnens socker- och energiintag jämfördes mellan måndag ‒ torsdag, fredag och helg. I en tredje studie genomförde 8 ‒ 12-åringar med övervikt eller fetma en kostregistrering med hjälp av digitalkamera vid upprepade tillfällen. I en fjärde studie utvecklades och anvä ndes en smartphoneapplikation för kostregistrering bland 15-åringar, som också använde en webb-baserad kostregistrering. Rapporterat EI med kostregistreringarna utvärderades i jämförelse med TEE mätt med SenseWear Armband, och EI och sockerintag under vardagar och helger undersöktes.

Resultat SDQ underskattade EI med 30 % bland de icke-gravida kvinnorna och en signifikant högre underskattning skedde bland kvinnorna med övervikt eller fetma. SDQ underskattade EI med 21 % bland de gravida kvinnorna. SDQ kunde dock rangordna EI bland kvinnorna med övervikt eller fetma och gav ett högre estimerat intag av flera näringsämnen och de flesta livsmedel jämfört med FFQ bland de icke-gravida kvinnorna. De nyutvecklade kostregistreringsmetoderna underskattade EI bland barn med 24 % och bland ungdomar med 29 %. Digitalkamerametoden visade god reproducerbarhet för de olika mättillfällena bland barn. Smartphoneapplikationen kunde uppskatta ungdomars TEE och pojkars fysiska aktivitetsnivå med en fråga om den dagliga fysiska aktiviteten. Underskattning av EI ökade med BMI och var lägre när en helgdag fanns med i kostregistreringen för både barn och ungdomar. Bland barnen iv underskattades EI mer bland flickor än pojkar och underskattningen ökade med åldern. Det fanns ingen signifikant skillnad i intagsmängd av näringsämnen och livsmedel när de mättes med smartphoneapplikationen jämfört med den webb-baserade kostregistreringen, och flera näringsämnen och livsmedel var signifikant korrelerade mellan de båda metoderna. EI hos barn i Europa skilde sig inte åt mellan vardagar och helger, men det totala intaget av mono- och disackarider och/eller livsmedel med hög andel tillsatt socker eller sackaros var generellt högre på helgerna. Sockerintaget på fredagar var ett mellanting mellan intaget under vardagar och helger hos de europeiska barnen.

Konklusion De nyutvecklade kostundersökningsmetoderna fångade i genomsnitt mellan 70 % och 79 % av EI bland barn, ungdomar och unga kvinnor, och förmågan att rangordna EI var generellt låg med metoderna. Liksom i tidigare studier underskattades EI i högre grad hos de med övervikt/fetma eller högre BMI i alla grupperna, och bland barn och ungdomar framkom att validiteten ökade med en helgdag i kostregistreringen som en ny påverkande faktor. Barns och ungdomars sockerintag var generellt högt och som högst under helgen. Det finns ett stort behov av fortsatt forskning för att förbättra kostundersökningsmetoders validitet och användarvänlighet. För kostregistreringsmetoder som använder sig av teknik bör fokus i vidareutvecklingen vara på att göra det enklare för användaren att registrera konsumerade livsmedel och portionsstorlekar, till exempel genom att automatisera dessa steg i så hög grad som möjligt. SDQ kan anpassas och utvärderas även i andra grupper och för olika syften. Faktorer med betydelse för en korrekt rapportering av kost intaget bör tas i beaktande även fortsättningsvis samt undersökas vidare. För att göra det möjligt att utvärdera intaget av socker i jämförelse med näringsrekommendationer bör information om mängden tillsatt socker i livsmedel inkluderas i livsmedelsdatabaser.

Objective: First, to evaluate the ability of a short dietary questionnaire (SDQ) to estimate energy intake (EI) on group and individual levels compared with total energy expenditure (TEE) measured by the doubly labelled water method. Second, to compare the SDQ's performance in estimating energy, nutrient and food intakes with a sixty-six-item FFQ used in large-scale Swedish epidemiological research. Design: Cross-sectional. Setting: Umea, Sweden. Subjects: In total, sixty-five non-pregnant women, of whom thirty-one were overweight or obese, and twenty-five pregnant, normal-weight women completed the protocol. Results: On average, the SDQ captured 78% and 79% of absolute TEE in the non-pregnant and pregnant normal-weight women, respectively. Furthermore, the SDQ captured an average of 57% of TEE in the overweight/obese nonpregnant women. The Spearman correlation of EI and TEE was significant in the overweight and obese women only (rho=0.37, 95% CI 0.02, 0.64). There was no significant difference between the SDQ and the more extensive FFQ in the ability to assess EI when compared with TEE. Intakes of most nutrients and foods were significantly higher when assessed with the SDQ compared with the FFQ. Conclusions: A new short dietary questionnaire with an alternative design underestimated EI of non-pregnant and pregnant, overweight and obese women on a group level but was able to rank the overweight/obese women according to EI. Furthermore, the short questionnaire captured as much or more of the energy, nutrient and food intakes of non-pregnant normal-weight and overweight/obese women on the group level as a traditional, more extensive FFQ.

OBJECTIVE: To examine differences in intake of energy (EI), sugars, and sucrose-rich foods and drinks between weekdays (Monday through Thursday), Fridays and weekends in European children.

METHODS: Twenty-four hour recall data were used for children aged 2-9 years from Belgium, Cyprus, Estonia, Germany, Hungary, Italy, Spain and Sweden, participating in the IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health EFfects In children and infantS) study at baseline 2007-2008. Dietary intake was reported by parents and complemented by day-care or school personnel when needed. Children with complete interview days for whom all main meals were known and that had a reported EI between 500-5000 kcal/day were included with one day each. For children with more than one 24-hour recall weekends were chosen over weekdays in order to obtain a balanced distribution of days of week. Regression models adjusted for country, age and sex were performed to investigate differences in EI, sugars (g/day) and sucrose-rich foods and drinks (g/day) on weekdays (Monday through Thursday) versus weekends (n=9339), as well as Fridays versus weekdays and weekends (n=9496), respectively. Models with intake of sugars and sucrose-rich foods and drinks as dependent variables were additionally adjusted for EI. The analysis comparing intake on weekdays versus weekends was stratified by country for Belgium, Cyprus (excluding sugars), Germany, Hungary, Italy, Spain and Sweden.

RESULTS: Intake of energy (t(9338)=4.1, p<0.001), sugars (t(8189)=7.6, p<0.001), and sucrose-rich foods and drinks (t(9338)=6.4, p<0.001) were higher on weekends versus weekdays. Intake on Fridays was a cross between the intakes on weekdays and weekends and did not differ from them, except for intake of sucrose-rich foods and drinks, being lower on Fridays compared with weekends (t(9495)= -2.2, p=0.02). Stratified analyses showed higher EI on weekends versus weekdays in Hungary (t(1532)=7.7, p<0.001). Intake of sugars was higher on weekends versus weekdays in Hungary (t(1532)=5.6, p<0.001), Italy (t(1974)=4.5, p<0.001) and Sweden (t(1224)=6.0, p<0.001), but in Belgium it was lower on weekends versus weekdays (t(372)= -2.0, p=0.04). Intake of sucrose rich foods and drinks was higher on weekends versus weekdays in Cyprus (t(1148)=2.8, p=0.01), Hungary (t(1532)=2.9, p=0.004), Italy (t(1974)=9.0, p<0.001) and Spain (t(623)=3.0, P=0.003).

CONCLUSION: Dietary intake of European children differed on weekdays (Monday through Thursday) versus weekends, and intake on Fridays was a cross between the intakes on these days. The results imply the importance to capture dietary intake of children on both weekdays and weekends when assessing their habitual intake with 24-hour recalls.