Table 1.

Alcohol use behavior per quintile of alcohol use in 14 496 twins

	Quintile N %
	1	2	3	4	5
	3343	2485	2870	3982	1816
	23.1%	17.1%	19.8%	27.5%	12.5%
Questionnaire 2
Do you drink beer?
No (%)	99.6	85.3	37.9	5.1	3.8
Less than one unit per day (%)	0.4	14.6	60.8	93.2	77.9
1–2 units per day or more than two units per day (%)	0.0	0.0	0.9	1.6	14.0
More than one unit per day (%)	0.0	0.0	0.3	0.1	4.3
Responses (n)	3171	2237	2656	3833	1604
Non-response (n)	172	248	214	149	212
Do you drink wine?
No (%)	99.4	77.3	38.1	7.2	9.0
Less than one unit per day (%)	0.6	22.2	61.9	92.5	86.2
1–2 units per day or more than two units per day (%)	0.0	0.5	0.0	0.2	4.4
More than one unit per day (%)	0.0	0.1	0.0	0.1	0.4
Responses (n)	3171	2237	2656	3833	1604
Non-response (n)	172	248	214	149	212
Do you drink liquor?
No	99.6	71.8	19.7	2.58	1.2
Less than one unit per day	0.4	28.3	79.7	97.3	88.8
1–2 units per day or more than two units per day	0.0	0.0	0.6	0.1	8.4
More than one unit per day	0.0	0.0	0.0	0.0	1.6
Responses (n)	3171	2237	2656	3833	1604
Non-response (n)	172	248	214	149	212
Questionnaire 3
Have you drunk alcohol in the last year?
Yes (%)	0.9	95.1	99.5	99.9	99.9
Responses (n)	987	1606	1501	1473	1428
Non-response (n)	2356	879	1369	2509	388
How often do you drink alcohol?
Never	88.9	3.5	0.5	0.0	0.0
Less than once a month	11.1	68.4	30.1	2.3	0.0
About once a month	0.0	16.0	32.0	11.5	0.5
2–3 times per month	0.0	10.0	27.3	48.2	9.6
About once per week	0.0	1.7	8.6	34.0	50.9
2–4 times per day	0.0	0.3	1.3	3.6	33.7
Every day or almost every day	0.0	0.0	0.3	0.3	5.3
Responses (n)	902	1709	1610	1546	1486
Non-response (n)	2441	776	1260	2436	330
How many bottles of beer did you drink last week?
0	99.24	91.0	75.1	47.0	21.8
1	0.76	5.5	14.5	26.7	17.6
2	0.0	2.0	6.0	14.9	20.0
3	0.0	0.7	1.9	5.0	10.3
4	0.0	0.2	1.1	2.5	9.3
5	0.0	0.1	0.3	1.5	4.7
6	0.0	0.1	0.3	0.9	5.3
7	0.0	0.1	0.1	0.7	3.4
8	0.0	0.3	0.4	0.6	4.1
≥9	0.0	0.1	0.2	0.4	3.5
Responses (n)	395	1516	1478	1463	1442
Non-response (n)	2948	969	1392	2519	374
How many glasses of wine did you drink last week?
0	98.7	83.5	69.2	49.5	29.5
1	0.8	7.5	10.3	10.7	5.9
2	0.26	5.7	12.8	22.5	18.0
3	0.26	1.8	3.7	8.2	13.0
4	0.0	0.7	2.1	5.0	13.2
5	0.0	0.3	0.7	1.3	5.5
6	0.0	0.1	0.7	1.3	6.1
7	0.0	0.1	0.1	0.6	3.8
8	0.0	0.1	0.2	0.4	2.7
≥9	0.0	0.1	0.1	0.4	2.3
Responses (n)	392	1500	1480	1432	1368
Non-response (n)	2951	985	2870	2550	448
How many drinks of liquor did you drink last week?
0	100.0	91.8	79.4	60.6	36.1
1	0.0	4.6	10.6	15.3	13.6
2	0.0	2.4	5.3	12.9	18.2
3	0.0	0.7	2.4	4.3	10.6
4	0.0	0.1	1.0	3.8	7.9
5	0.0	0.0	0.6	1.4	4.7
6	0.0	0.1	0.3	0.4	3.1
7	0.0	0.1	0.1	0.6	2.2
8	0.0	0.1	0.3	0.5	1.8
≥9	0.0	0.1	0.1	0.35	1.8
Responses (n)	381	1488	1459	1432	1402
Non-response (n)	2962	997	2870	2550	414
How often do you drink five units of alcohol?
Never	97.9	59.8	36.6	22.3	7.1
1–4 times per year	2.0	32.9	40.5	33.0	15.5
5–10 times per year	0.1	6.2	15.7	22.6	17.7
Once per month	0.0	1.1	4.3	12.2	17.6
2–3 times per month	0.0	0.1	1.2	7.0	17.6
Once per week	0.0	0.0	0.9	2.6	18.9
2–4 times per week	0.0	0.0	0.0	0.3	4.9
Almost every day or every day	0.0	0.0	0.0	0.0	0.9
Responses (n)	980	1696	1.613	1530	1481
Non-response (n)	2363	789	1257	2452	335