A cross sectional descriptive study was conducted to identify the commonly consumed free sugar containing food and beverage items by the pre-school children in Colombo. Prior to conducting the study, ethics approval was obtained from the ethics review committee, Faculty of Medicine, University of Colombo, Sri Lanka (EC-17-001). Written informed consent was obtained from all the primary caregivers of the selected children who participated in the study.
For the initial phase of the study 518, apparently healthy 04-05-year-old preschool children were enrolled randomly from 26 preschools in the district of Colombo, Sri Lanka. All included children were those who had resided in the district from birth, were not on a special diet and had a primary caregiver was available for data collection. These 26 preschools were selected as two random preschools from all 13 district secretariat divisions in the Colombo district.
Development of the food frequency questionnaire:
During this phase, all the food and beverage consumption data of included children were collected by face-to-face interviews with the primary caregivers based on 24-hour dietary recalls (24hDR), covering one weekend day and two weekdays. From these, all food and beverage items that contained sugar were extracted, and then the foods and beverages that contributed 95% of the sugar intake were identified by stepwise regression. The final dietary inventory list included 60 sugar-containing food and beverage items, as well as seven food and beverage items to which caregivers commonly added sugar at the time of consumption.
Finally, the identified sugar-containing food and beverage items were classified into seven categories by two nutrition specialists based on similarity of consistency and preparation methods    as: bakery products, biscuits, sugar confectionery, chocolate confectionery, sugar-sweetened beverages, desserts. Remaining items were classified as miscellaneous sweets. In the FFQ these were asked in order of descending frequency of intake. Frequency options were included as ‘never’ or ‘times per day/per week or per month’ for the respondent to write the frequency in numbers in the relevant column. In measuring the intake of a particular nutrient, precise quantification of the food and beverage intake is vital. Thus, commonly used measures for quantification of each food and beverage item were identified: for example, different sizes of glasses, cups and spoons. Along with those, some actual food items were identified in available smallest portions in the market, such as toffees, pieces of chocolate, biscuits some more. A power-point presentation was developed, including these, and measuring instruments were identified to demonstrate at the time of data collection. The FFQ was originally developed in Sinhala and translated to Tamil and English using backwards and forward translation methodology. It was pretested among 20 caregivers of pre-school children for the clarity of the instructions given and the food names, according to the findings, a few alterations were done.
Compilation of the food composition database
Since the existing food composition databases for Sri Lankan foods do not provide accurate free sugar content of these sugary foods, the researchers compiled a comprehensive database on the free sugar content of the identified 60 foods and beverage items employing a number of methods used in the compilation of food composition databases  : the recipes from reputed Sri Lankan culinary books, information gleaned from food labels, recipes and analytical reports from local manufacturers were among them.
Due to non-availability of a gold standard method for assessment of diet, criterion validity of the food frequency questionnaire cannot be evaluated. Thus, to assess relative validity, free sugar intake measures derived from FFQ were compared with free sugar intake measures derived from three 24-hour dietary recalls (24hDR) for three days as the reference method     . The test-retest reliability of the FFQ was determined by administering the same FFQ twice to the same population over a six-week period.
During the validation phase of the study, we recruited an additional 113 preschool children aged 04-05 from 10 preschools, as a minimum sample size was required to achieve a 5% significance level and 80% power to demonstrate a minimum correlation of 0.3 (24) and 10% of non-response. However, only 108 participants completed both stages of data collection. As the FFQ was developed to assess the sugar intake of preschool children in Colombo District in the next phase, to avoid contamination validation study was conduct in two adjacent district secretariat outside Colombo District. Simple random sampling was used to select five preschools from each area. Healthy children who did not follow a special diet and whose primary caregivers were available for data collection were included in the study after receiving informed consent.
Data was obtained by meeting with the child’s primary care giver twice in two days. The same FFQ was completed as a self-administered questionnaire at the first visit (FFQ1) and at the second visit (FFQ2) six weeks later. Participants gathered in groups of 10 in a hall, and the researcher gave clear instructions to complete the FFQ, followed by exercises with some hypothetical examples. The FFQ was then completed based on the child's usual diet for the past three months. When participants completed the FFQ, use a power-point presentation to illustrate serving sizes for each food and drink.
Again, all necessary directions to complete the 24hDR were provided both orally and in print, and caregivers were trained to complete these at home over two weekdays and one weekend. They were encouraged to choose days that reflected the child’s usual diet. They received printed manual on how to choose the serving size.
Calculation of sugar intake;
The total daily free sugar intake of each child was calculated, separately through FFQ1, FFQ2 and the three 24hDR.
- Using the FFQ, free sugar intake from each food and beverage item per day was calculated.
Sugar intake from particular = Amount of intake x Frequency of x Free sugar concentration
Food/ beverage item intake of the item
Daily intake of sugar was calculated by dividing weekly intake by 7 and monthly intake by 30.4. The total daily intake was calculated adding all these daily sugar intake values
- Using 24HDR sugar intake was calculated by,
Sugar intake from particular = Amount of intake x Free sugar concentration
Food/ beverage item of the item
Adding sugar intake from each item the daily sugar intake was calculated, mean sugar intake for the three days was taken for final comparison.
Validity was assessed through comparison of sugar intake calculated from FFQ1 and FFQ2 separately with the mean sugar intake calculated from three 24hDRs, while reliability was assessed through comparison of sugar intake values calculated from FFQ1 and FFQ2.
Data was analyzed using SPSS version 21. The following statistical methods were used for the comparison; comparison of the means by calculating the mean percentage difference, Wilcoxon sign rank test, a relative agreement between two methods was assessed by ranking cross-classification and weighted kappa coefficient, Spearman correlation was used to measure the degree to which the two administrations are related along with intraclass correlation (reliability only) and Bland–Altman method was used to measure the agreement between the daily sugar intake values obtained from FFQ and 3hDR throughout the range of intake . Several statistical approaches were utilized simultaneously as they analyze various aspects of validity and reliability at group level, individual-level and throughout the range of free sugar intake levels.