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

A comparison of different approaches to measure alcohol consumption

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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