Table 1

Baseline characteristics of the analysis cohort, Nord-Trøndelag Health Study, Norway, 1995–1997 (n=18 894)

Characteristic	Inactive		Very low		Low		Moderate		High
	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD
Age	39.3	8.8	40.2	8.6	39.8	8.7	39	8.8	37.6	9.7
BMI	26.3	4.3	26	4	25.8	3.8	25.4	3.5	25.2	3.3
	n	Per cent	n	Per cent	n	Per cent	n	Per cent	n	Per cent
Sex
Men	543	56.2	1482	37.4	2170	45.7	3103	45.8	1561	64.2
Women	423	43.8	2482	62.6	2583	54.3	3675	54.2	872	35.8
Family history of asthma
No	739	76.5	3075	77.6	3710	78.1	5313	78.4	1925	79.1
Yes	133	13.8	583	14.7	715	15.0	998	14.7	328	13.5
Don’t know	94	9.7	306	7.7	328	6.9	467	6.9	180	7.4
Education
Low	301	31.2	905	22.8	836	17.6	851	12.6	355	14.6
Mid	546	56.5	2174	54.8	2584	54.4	3553	52.4	1300	53.4
High	109	11.3	857	21.6	1302	27.4	2344	34.6	759	31.2
Missing	10	1.0	28	0.7	31	0.7	30	0.4	19	0.8
Social benefit
No	547	56.6	2443	61.6	3138	66.0	4560	67.3	1618	66.5
Yes	219	22.7	748	18.9	797	16.8	1043	15.4	337	13.9
Missing	200	20.7	773	19.5	818	17.2	1175	17.3	478	19.6
Economic difficulties
No	480	49.7	2226	56.2	2811	59.1	4108	60.6	1484	61.0
Yes	326	33.7	1140	28.8	1334	28.1	1811	26.7	566	23.3
Missing	160	16.6	598	15.1	608	12.8	859	12.7	383	15.7
Smoking status
Never	349	36.1	1672	42.2	2188	46.0	3405	50.2	3405	50.2
Former	232	24.0	958	24.2	1230	25.9	1674	24.7	1674	24.7
Current	375	38.8	1311	33.1	1312	27.6	1653	24.4	1653	24.4
Missing	10	1.0	23	0.6	23	0.5	46	0.7	46	0.7
Allergic rhinitis
No	649	67.2	2678	67.6	3283	69.1	4640	68.5	1604	65.9
Yes	111	11.5	570	14.4	711	15.0	1031	15.2	362	14.9
Missing	206	21.3	716	18.1	759	16.0	1107	16.3	467	19.2
Total	966	5.1	3964	21.0	4753	25.2	6778	35.9	2433	12.9