A comparison of different approaches to measure alcohol consumption
26 April 2006Ola Ekholm, Karina Christensen, Katrine Strandberg Larsen
and Morten Grønbæk National Institute of Public Health
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Background
•Self-reported alcohol intake
•Possible to link mortality and morbidity with drinking behaviour on an individual level
•The recommended guidelines for alcohol intake are, to a great extent, based on epidemiological studies that have
used self-reported information
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•More specific questions result in higher reported alcohol intake
•Beverage-specific questions
•Large time-variation in drinking
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Aim of the study
To compare the reported intake obtained by beverage-specific questions and to compare how different reference periods and response formats influence the self-reported
alcohol intake.
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Danish Health Interview Survey 2003
Sample n Response rate (%)
1 1000 64.72 1000 63.03 1000 65.54 1000 67.5
Inclusion criteria: Danish citizen aged 18 years or more.
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Characteristics of the respondents in each sample
by sex, age and marital status. Percentage
1 2 3 4Sex
Men 49 47 47 46
Age18-29 y. 18 14 18 1530-44 y. 29 30 29 3145-65 y. 34 38 36 3666+ y. 19 18 18 19
Marital statusMarried 56 55 55 54Cohabiting 14 17 18 13Single (separated, divorced, widowed)Single (unmarried) 17 15 16 17
Sample
14 13 12 16
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Question included in all four samples
How many alcoholic drinks did you have during last weekday? (don’t include Friday, it is considered part of the weekend)
No. of drinks Beer __
Strong beer __ Red & white wine __ Liqueurs __ Spirits __ Ready to drink products __
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1 bottle of beer = 1 drink 1 bottle of spirits = 25 drinks1 bottle of strong beer = 1.5 drinks 1 glass red/white wine = 1 drink1 bottle of red/white wine = 6 drinks 1 glas of liqueur = 1 drink1 bottle of liqueur 70 cl. = 10 drinks 1 glas of aquavit = 1 drink
1 drink = 12 grams of alcohol
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Alcohol intake on the most recent weekday
1 2 3 4Mean number of drinks 1.1 1.2 1.1 1.2
At least one drink (%) 40 43 44 41
No. of respondents 644 626 650 673
Sample
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Sample1 How many alcoholic drinks did you have each day last week?
We'll start with yesterday and take one day at a time.
2 How many alcoholic drinks do you have each day in a typical week? We'll start with Monday and take one day at a time.
3 How many drinks did you have during the last weekend? (that includes Friday, Saturday and Sunday)
4 How many alcoholic drinks do you have on average per week?
Question
All questions were beverage-specific (beer; strong beer; red & white wine; liqueurs; spirits; ready to drink products)
Four different assessment methods for alcohol consumption
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The sex- and age-adjusted weekly mean number of alcoholic drinks
0
2
4
6
8
10
12
7- day recallmeasure (sample 1)
Intake each day ina typical week
(sample 2)
Average weeklyintake (sample 4)
Mea
n n
um
ber
of
dri
nks
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The age-adjusted weekly mean number of alcoholic drinks. Men
0
2
4
6
8
10
12
14
16
7- day recallmeasure (sample 1)
Intake each day ina typical week
(sample 2)
Average weeklyintake (sample 4)
Mean n
um
ber
of
dri
nks
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The age-adjusted weekly mean number of alcoholic drinks. Women
0
2
4
6
8
7- day recallmeasure (sample 1)
Intake each day ina typical week
(sample 2)
Average weeklyintake (sample 4)
Mean n
um
be
r of
dri
nks
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The Danish National Board of Health’s sensible drinking limits
Men: a maximum of 21 drinks per week
Women: a maximum of 14 drinks per week
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Results from a multivariate logistic regression analysis showing the association between a high reported weekly
alcohol intake and the different assessment methods
0.4
0.6
0.8
1
1.2
1.4
7- day recallmeasure (sample 1)
Intake each day ina typical week
(sample 2)
Average weeklyintake (sample 4)
Odds R
ati
o
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Conclusion
•A question concerning the intake in a typical week does not seem to underestimate the alcohol intake compared to the 7-
day recall measure
•Estimating the intake for a typical week will take the large time-variation in drinking into account
•The average weekly intake measure was less specific than the other two measures and the lower reported intake was
therefore as expected.
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Questions concerning binge drinking
Sample1 Within the past 3 months, how many times did you
have five or more drinks on a single occassion ?
2 Within the past 3 months, how many times did you have five or more drinks on a single occassion ?
3 Within the past year, how many times did you have five or more drinks on a single occassion ?
4 Within the past year, how many times did you have five or more drinks on a single occassion ?
Close-ended
Open-ended
Questions Response formatClose-ended
Open-ended
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Close-ended response categories
Never
Less than once a month
Approximately 1-3 times a month
Approximately once a week
More than once a week
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Binged at least once a week
Sample % OR 95% CI
1 10.1 1
2 4.1 0.38 (0.24-0.62)
3 11.3 1.15 (0.80-1.66)
4 4.2 0.41 (0.26-0.66)1-year
Response format
close-ended
open-ended
close-ended
open-ended
Reference period
3-month
3-month
1-year
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Binged at least once a month
Sample % OR 95% CI
1 41.5 1
2 34.6 0.75 (0.59-0.96)
3 39.3 0.90 (0.71-1.15)
4 25.4 0.47 (0.36-0.60)
Reference period Response format
3-month close-ended
1-year open-ended
3-month open-ended
1-year close-ended
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Conslusion
•The open-ended response format is not advisable when the reference period is long
•The analyses showed that the reference period was important for the self-reported intake for the open-ended questions. However, this was not the
case for the close-ended questions
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Summary
•A question concerning typical alcohol intake is feasible to use in epidemiological studies
•It is more appropriate to use close-ended questions compared to open-ended questions
when the reference period is long
•The length of the reference period seems to be ignorable for the self-reported frequency of binge
occasions when using close-ended questions