Table 2.

Characteristics of inpatients with head injury involved in two-wheeled vehicle crashes

	Two-wheeled vehicles					Motorcyclists					Bicyclists
	Cases		Controls		P value	Cases		Controls		P value	Cases		Controls		P value
	n	%	n	%		n	%	n	%		n	%	n	%
Total	82 711	6.7	1 156 763	93.3		76 352	6.5	1 099 277	93.5		6359	10.0	57 486	90.0	<0.001
Gender
Male	48 373	7.1	634 478	92.9	<0.001	44 706	6.9	601 593	93.1	<0.001	3667	10.0	32 885	90.0	0.523
Female	34 338	6.2	522 285	93.8		31 646	6.0	497 684	94.0		2692	9.9	24 601	90.1
Age group (years)
<18	5123	9.4	49 354	90.6	<0.001	3718	10.5	31 846	89.5	<0.001	1405	7.4	17 508	92.6	<0.001
18–40	38 471	5.2	697 198	94.8		37 955	5.2	689 948	94.8		516	6.6	7250	93.4
41–64	26 380	7.9	307 322	92.1		24 659	7.8	291 586	92.2		1721	9.9	15 736	90.1
65+	12 737	11.0	102 860	89.0		10 020	10.4	85 874	89.6		2717	13.8	16 986	86.2
Location
Highly urbanised area	8815	3.6	237 868	96.4	<0.001	8218	3.5	227 548	96.5	<0.001	597	5.5	10 320	94.5	<0.001
Medium urbanised area	23 379	5.5	401 279	94.5		21 743	5.4	383 541	94.6		1636	8.4	17 738	91.6
Boomtown	20 149	7.0	268 552	93.0		18 709	6.8	255 449	93.2		1440	9.9	13 103	90.1
General township	18 924	9.8	174 893	90.2		17 251	9.5	163 844	90.5		1673	13.2	11 049	86.8
Rural area	11 444	13.4	73 818	86.6		10 431	13.2	68 556	86.8		1013	16.1	5262	83.9
Motorcycle engine capacity
≥51 cc	60 411	6.2	907 379	93.8	<0.001	60 411	6.2	907 379	93.8	<0.001	NA	NA	NA	NA	NA
≤50 cc	15 941	7.7	191 898	92.3		15 941	7.7	191 898	92.3		NA	NA	NA	NA
Drunk driving
No (BAC ≤0.03%)	71 070	6.0	1 108 293	94.0	<0.001	64 876	5.8	1 051 700	94.2	<0.001	6194	9.9	56 593	90.1	<0.001
Yes (BAC >0.03%)	11 641	19.4	48 470	80.6		11 476	19.4	47 577	80.6		165	15.6	893	84.4
Helmet use
Yes	63 575	5.9	1 011 701	94.1	<0.001	63 158	5.9	1 006 568	94.1	<0.001	417	7.5	5133	92.5	<0.001
No	19 136	11.7	145 062	88.3		13 194	12.5	92 709	87.5		5942	10.2	52 353	89.8
License
Yes	57 613	5.7	952 109	94.3	<0.001	57 613	5.7	952 109	94.3	<0.001	NA	NA	NA	NA	NA
No	16 028	11.0	129 169	89.0		16 028	11.0	129 169	89.0		NA	NA	NA	NA

BAC, blood alcohol concentration; NA, not applicable.