National Diet and Nutrition Survey (NDNS)

rolling programme

Gillian Swan

Nutrition Division

Food Standards Agency

Food Standards AgencyAims include:

• To make it easier for all consumers to choose a healthy diet and so improve quality of life by reducing diet-related disease

• To continue to reduce food-borne illness and the risks to consumers from chemical contamination of food throughout the UK.

National Diet and Nutrition Survey programme (NDNS)

• Major component of Agency’s dietary survey programme.

• In its previous form - a series of cross-sectional surveys of different age groups

• Now setting up a rolling programme to collect data continuously

NDNS programme as it was• Series of cross-sectional surveys of diet and

nutritional status covering discrete population age groups

• Dietary assessment - weighed record for four or seven days

• Blood and urine sample • Contextual information – physical measurements,

physical activity, lifestyle characteristics

Survey Fieldwork Report

Children aged 1½ - 4½ years 1992/93 1995

Young people aged 4 - 18 years 1997 2000

Adults 19 - 64 years 2000/01 2002-04

People aged 65 years and over 1994/5 1998

National Diet and Nutrition Survey Programme

Features of the NDNS

• Cross-sectional

• Data collected on individuals

• Detailed food consumption data

• Linked data on food, nutrient intake, nutritional status and contextual information in individuals

Need for NDNS data• Underpins Agency’s work to protect

consumer safety & promote healthy diets.– Detailed food consumption data essential for

assessing exposure to food chemicals– Assess nutritional issues in the population

and identify where action needed– Means of measuring progress towards

Government targets and objectives

Why change the approach?

• Concerns about current programme• Lack of timeliness - 15 year gap between

surveys• Lack of flexibility• Declining response rates • Data quality (under-reporting)

• Agreement from Agency’s Board to move to rolling programme

Features of rolling programme

• Survey runs continuously - fieldwork every year

• Data points generated more frequently - better tracking of trends over time

• Greater flexibility to collect additional data or boost sample for specific groups

Features of rolling programme

• Core programme - 1000 people per year (adults and children)

• All ages from 1½ years upwards • Designed to be representative of the UK

population• Excludes infants, pregnant women,

people in institutions

Rolling programme – components (1)

• Face to face interview

• Dietary assessment

• Physical measurements • height

• weight

• waist and hip circumference

• mid-upper arm circumference (children)

• Blood pressure

Rolling programme - components (2)

• Blood sample analysed for range of nutritional status indices

• 24-hour urine collection (salt intake)

• Physical activity questionnaire

Dietary assessment• Require detailed quantitative data on

food consumed by each respondent

• Weighed record used for previous NDNS - but high respondent burden

• Response rates declining

• Concern about under-reporting

Choice of Dietary Assessment Method

• Pilot work to compare two methods– Multiple pass 24 hour recall

• 4 non-consecutive days

– Unweighed diary• 4 consecutive days

• Compare response rates and data quality to decide on best method

NDNS rolling programme timetable

• Comparison study to choose dietary assessment method – spring 2007

• Dress rehearsal - early 2008

• Rolling programme fieldwork commences April 2008

• Results for first year 2008/09 available end of 2009

Reports and Datasets

• Key results published on FSA website annually (www.food.gov.uk)

• Datasets sent to the Data Archive annually

• Printed report with commentary to cover first four years results

How can the data be used?

• Monitor trends & progress towards targets

• Compare intakes with recommendations• Describe characteristics of people with

low (or high) intakes/status• Modelling changes in diet or composition• Other uses ……..