Table 2.

Prevalence of childhood atopic medication purchases in ages 0–15 (%) by (A) birth order and number of siblings for the full population and (B) age difference with second-born sibling for first-born children. Birth cohorts 1995–2004

	N	Antihistamines	Eczema medication	Asthma medication	Epinephrine
A) Birth order (#) by number of children in the family
#1/1	88 481	43.1	33.3	20.0	2.8
#1/2	112 893	42.7	33.5	20.1	3.4
#2/2	111 258	38.1	31.6	18.1	2.8
#1/3	46 389	39.3	31.6	18.7	3.3
#2/3	48 000	34.6	29.3	17.1	2.6
#3/3	51 630	33.4	28.4	15.3	2.3
#1/4+	19 113	32.8	28.1	15.6	2.5
#2/4+	19 237	29.5	26.7	15.3	2.2
#3/4+	20 888	27.4	25.8	14.9	2.0
#4+/4+	41 188	23.7	23.9	13.0	1.4
Total	559 077	37.2	30.7	17.8	2.8
B) First-born’s age difference with second-born
Twins	9 237	37.0	28.4	20.6	2.3
1 year	21 650	35.7	30.3	16.9	2.6
2 years	66 300	40.1	32.5	18.6	3.5
3 years	39 629	42.4	32.9	20.1	3.4
4 years	18 831	43.4	33.8	20.2	3.4
5 + years	22 748	43.7	33.7	20.6	3.4
Only child	88 481	43.1	33.3	20.0	2.9
Total	266 876	41.5	37.7	19.5	3.2