Development and validation of a food-based diet quality index for New Zealand adolescents

BMC Public Health

Table 1 Components and scoring of the New Zealand Diet Quality Index for Adolescents (NZDQI-A)

Component	Elements of NZDQI-A				Criteria to achieve maximum component score⁴
	‘Variety’	‘Adequacy’
	Score¹(v/V)	Indicators in the FQ²	Cut-offs³	Score (A)
FRUIT	v/6	Servings of fruit per day⁵.	0 serving/day	0	Consumed at least 2 daily servings of fruits from 6 varieties in a week.
			< 2 serving/day	10
			≥ 2 servings/day	20
VEGGIE	v/6	Servings of vegetables per day⁶.	0 serving/day	0	Consumed at least 3 daily servings of vegetables from 6 varieties in a week.
			< 3 servings/day	10
			≥ 3 servings/day	20
CEREAL	v/3	Servings of bread per day.	0 serving/day	0	Consumed at least 6 daily servings of cereals from 3 varieties in a week.
		Servings of pasta, rice, muesli, porridge or breakfast cereals per week.	< 6 servings/day	10
			≥ 6 servings/day	20
DAIRY	v/4	Frequency intake of milk (standard and non-standard milk), flavoured milky drink, cheese and yoghurt⁷	0 serving/day	0	Consumed at least 3 daily servings of milk or milk products from 4 varieties in a week.
			< 3 servings /day	10
			≥ 3 servings/day	20
MEAT	v/7	Servings of meat, chicken, seafood, eggs or meat alternatives eaten per day.	0 serving/day	0	Consumed 1 or 2 daily servings of meat or alternatives (not including processed meats) from 7 varieties in a week.
			< 1 serving/day	5
			1-2 servings/day	20
			> 2 servings/day	10
Total Score	= Σ (v/V) x A = FRUIT + VEGGIE + CEREAL + DAIRY + MEAT

Food Questionnaire (FQ), Fruits (FRUIT), Vegetables (VEGGIE), Bread and cereals (CEREAL), Milk and milk products (DAIRY), Meat and alternatives (MEAT).
¹ Ratio calculated as the different sub groups (v) consumed at least once in a week (as indicated in the NZAFFQ) divided by the total sub groups (V) in a food group. The food sub groups are outlined in Additional file 1.
² Refers to questions in the FQ.
³ Based on achievement of the recommended daily servings as suggested by the Ministry of Health [33].
⁴ For each component, a total score is calculated by multiplying ‘Variety’ (v/V) by ‘Adequacy’ (A). The possible score range is 0 to 20. E.g. For a person who consumes at least two daily servings of fruits from three varieties in a week, FRUIT score = (3/6) × 20 = 10.
⁵ Include fresh, frozen, canned and stewed fruits.
⁶ Include fresh, frozen and canned vegetables, including potatoes.
⁷ Weekly frequency of intake (times per week) for the four sub groups as reported in the NZAFFQ. Weekly frequencies were summed and converted into daily frequencies. One time per day was equivalent to one serving.

ISSN: 1471-2458