Dietary and Nutritional Surveys Flashcards
Purpose of a Survey
Cross sectional examination at a given moment in time
Captures data on the world around you
Surveys
Cross sectional examination of what’s going on at a given moment
Representative sample
Tey are of maximum utility when combined with other snapshots # In time, or geography or societal # Detect trends # Determine relationships # Draw comparisons/ make distinctions
changes in dietary behaviour / trend
Occupational changes
Lifestyle changes
Changes in availability of food
Obesity prevalence
Technological changes= Internet, mobile communication
Life expectancy
Expectations of life
Education levels
Consumer demands
Occupational changes
# Decline of manufacturing and manual labour # Increase in service sector # Information industries
Lifestyle changes
# Pub visits # Gym usage # Restaurant usage # Smoking patterns
Changes in availability of food
# Economics # Climate change # Cultural change
Expectations of life
# Social mobility # Travel # Affluence # Social support
Consumer demands
Organic foods
Sustainable foods
Functional or added benefit foods
Healthy food options
Diet and Nutrition Surveys- Purpose
Dietary knowledge, behaviour and attitude assessments
Monitoring of general health in the population
Monitoring the diet quality, safety and nutritional status of the population # Identify nutritional problems # Risk groups # Changing patterns of consumption # Associations between patterns of consumption and disease risk # Evaluation of the effectiveness of government programs - Change for life
Informing public health policy
Food supply and demand determinations
Food supply- food balance sheets
# Per capita intake by nation # National comparisons can be made # Food availability # Not consumption # Assumes market prices can be met # Crude estimate of adequacy of the food supply # No data on distribution within the population # Wastage is very hard to measure = disproportionate
Household budget surveys
Expenditure and food survey:
~ National food survey
~ Family expenditure survey
# Household representatives are asked to report all food entering the household for 1 week # Expense and amount reported # Includes homegrown food
Expenditure and Food Survey Methodology
# Voluntary sample # Each household member over seven records food purchases for two weeks # In 2007 = 14647 people, 6141 households # (purchases not consumption) # Households classified according to a ‘Household reference person’: Income/ Social class
Expenditure and Food Surve
Run by the Office for National Statistics
Principal strength is that it dates backs to the 1940s
# Annual report of food and drink purchases by households in the UK # Identifies trends / Identifies geographical patterns in purchasing # In 2001 the survey was adapted to account for purchases outside the home #Nutritional context
Most recently ‘Family Food’
Household budget survey
Formerly the ‘national food survey’
Household budget surveys- uses
# Crude measure of changing patterns of expenditure on food # allow cross national comparisons
Household budget surveys - disadvantage
# Different means of collating information between surveys # Historically no record of food consumed outside of the home # Measure of purchases not consumption # Intrusive = Selectively representative # No measure of differences in consumption = Men, women, children within the house.
Individual surveys
Individuals are asked about their dietary consumption Questionnaire based # Food frequency questionnaires # 24 hour recalls # Food diaries
Data can be strengthened with analytical measures
# Optimum measure of food consumption by the individual # Provide data on diet, nutritional status, and general health of the population # In the UK the NDNS is the best available individual survey
NDNS Aims
To establish a database of the range of food, drink and nutrient intakes against which future changes in dietary habits could be assessed
To establish the average, and distributions of anthropometric, haematological, and biochemical measures of nutritional status against which future changes could be monitored
Provide detailed quantitative information on the food and nutrient intakes as a basis for Government policy
Describe the characteristics of individuals with intakes of specific nutrients that are above and below the national average
Provide a database to enable the calculation of likely dietary intakes risk assessment
Measure nutritional status or dietary biomarkers and to relate these to dietary, physiological and social data
Provide measurements of body size on a representative sample of individuals and examine their relationship to social, dietary, health and anthropometric data
Monitor the population diet and establish the extent to which it is adequately nutritious and varied
• Monitor the diet of specified groups and recommended by independent experts for optimal health, in order to act as a basis for policy development
National Diet and Nutrition Survey
First survey 1986/7 [Adults 16-64]
Last survey 2014 [Adults 19-64]
Ongoing rolling programme to update survey findings
Other surveys for the rest of the population:
above 64
aged 1½ to 4½ years
young people aged 4 to 18 years
Low Income Diet and Nutrition survey
NDNS design
2635 volunteers; Adults aged 16-64 living in private households
Pregnant women excluded
Only one individual per household [disadvant : Bias / Burden]
Sampling strategy - Multi-stage random probability design
Subjects were recruited in wards from electoral registers = 33 addresses per ward were targeted
NDNS- methodology
Interview questionnaire # Personal and household information, general info on dietary habits # Dietary supplementation # Medicines # Oral health
Seven day weighed food diary & physical activity diary # Food consumption in and out of the home
Tap water sample for fluoride assessment
Anthropometric measurements = Height, weight, wrist diameter, waist, hip and mid upper arm circumference
Blood pressure and heart rate
Blood collection
24 hr Urine Collection
Dietary intake- a weighed food diary
Measurement of total energy
Measurement of types of foods consumed
Measurement of macro and micronutrient intake
Measurement of foods consumed inside and outside of the home
Urinary Analytes
Markers of exposure:
Creatinine/ Sodium / Potassium/ Fluoride/ Urea
NDNS Venous Blood
slide 32- 33
Health Survey for England
Annual survey
Core topics
general health/ smoking/ drinking
fruit and vegetable consumption
height / weight / blood pressure measurements
Different focus each year:
cardiovascular disease
physical activity
Combining surveys
Secular trends in diet (left) and activity (right) in relation to obesity in Britain.
# Data for diet from National Food Survey # Data for body mass index from Office of Population Censuses and Surveys and historical surveys # Data for television viewing and car ownership from Central Statistical Office
Comparing populations- Three types of Survey
Nationwide surveys of individuals # National food consumption surveys= NDNS
Household Budget surveys # DAFNE project harmonises food budget surveys in European countries = Family food expenditure and food survey
Food Balance sheets # Food and agriculture organisation of the UN
European surveys
HBSC study (WHO): Health behaviour in school aged children 43 countries Cross sectional surveys 1983-2007
EPIC study:
European prospective investigation into cancer and nutrition
10 European countries
Populations diet characterised
Comparing regional intakes
using National food surveys
