National Diet and Nutrition Survey NDNS rolling programme

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National Diet and Nutrition Survey (NDNS)
rolling programme

• Gillian Swan
• Nutrition Division
• Food Standards Agency

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Food Standards Agency

• Aims 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.

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National Diet and Nutrition Survey programme
(NDNS)

• Major component of Agencys 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

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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

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National Diet and Nutrition Survey Programme
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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

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Need for NDNS data

• Underpins Agencys 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

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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 Agencys Board to move to rolling
  programme

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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

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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

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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

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Rolling programme - components (2)

• Blood sample analysed for range of nutritional
  status indices
• 24-hour urine collection (salt intake)
• Physical activity questionnaire

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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

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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

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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

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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

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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 ..