TABLE 3.

Risk of motor neurone disease with head injuries in different circumstances in a population‐based case–control study, New Zealand, 2013–2016

Exposure	All cases/controls (321/605) No %	OR	95% CI	OR1	95% CI	Male cases/controls (203/332) No %	OR	95% CI	OR1	95% CI	Female cases/controls (118/273) No %	OR	95% CI	OR1	95% CI
Circumstances of head injury
Never	224/483 (70/80)	1	Reference	1	Reference	134/248 (66/75)	1	Reference	1	Reference	90/235 (76/86)	1	Reference	1	Reference
Work‐related	14/11 (4/2)	2.25	0.98, 5.14	2.22	0.96, 5.12	12/9 (6/3)	2.46	0.97, 6.23	2.39	0.93, 6.10	2/2 (2/1)	1.81	0.22, 15.0	2.07	0.25, 17.4
Sport‐related	29/37 (9/6)	1.48	0.87, 2.52	1.39	0.81, 2.38	22/30 (11/9)	1.27	0.68, 2.36	1.18	0.63, 2.21	7/7 (6/3)	2.47	0.78, 7.88	2.34	0.73, 7.53
Leisure‐related	14/21 (4/3)	1.48	0.72, 3.03	1.50	0.73, 3.07	7/12 (3/4)	1.10	0.40, 3.06	1.13	0.40, 3.19	7/9 (6/3)	1.91	0.65, 5.65	1.83	0.61, 5.51
Traffic accident‐related	17/27 (5/4)	1.34	0.70, 2.57	1.30	0.67, 2.50	10/15 (5/5)	1.30	0.54, 3.12	1.28	0.53, 3.11	7/12 (6/4)	1.55	0.57, 4.21	1.47	0.54, 4.04
Other accidents	6/14 (2/2)	0.85	0.32, 2.31	0.85	0.31, 2.30	3/8 (1/2)	0.63	0.16, 2.48	0.61	0.15, 2.42	3/6 (3/2)	1.09	0.25, 4.84	1.09	0.24, 4.92
Multiple eventsª	17/12 (5/2)	2.65	1.21,5.83*	2.46	1.11, 5.44*	15/10 (7/3)	2.32	0.98, 5.50	2.15	0.90, 5.14	2/2 (2/1)	3.44	0.42, 28.1	3.30	0.39, 27.9
Frequency of head injury in different circumstances
Never	224/483 (70/80)	1	Reference	1	Reference	134/248 (66/75)	1	Reference	1	Reference	90/235 (76/86)	1	Reference	1	Reference
Work‐related
Once only	13/9 (4/1)	2.55	1.05, 6.21*	2.48	1.01, 6.09*	11/8 (5/2)	2.50	0.94, 6.64	2.39	0.89, 6.43	2/1 (2/0)	3.92	0.30, 52.0	4.46	0.33, 59.6
>1	1/2 (0/0)	0.85	0.08, 9.60	0.95	0.08, 10.66	1/1 (0/0)	2.02	0.12, 34.2	2.14	0.13, 35.86	0/1 (0/0)	—	—	—
Sport‐related
Once only	18/31 (6/5)	1.13	0.60, 2.11	1.06	0.56, 1.98	14/25 (7/8)	1.04	0.51, 2.14	0.98	0.47, 2.02	4/6 (3/2)	1.53	0.38, 6.11	1.33	0.33, 5.40
>1	11/6 (3/1)	3.24	1.14, 9.22*	3.05	1.06, 8.77*	8/5(4/2)	2.32	0.69, 7.82	2.07	0.61, 7.05	3/1 (3/0)	7.57	0.72, 79.2	8.52	0.80, 90.9
Leisure‐related
Once only	10/19 (3/3)	1.09	0.49, 2.43	1.08	0.48, 2.42	5/11 (2/3)	0.75	0.24, 2.39	0.77	0.24, 2.47	5/8 (4/3)	1.40	0.41, 4.80	1.29	0.37, 4.48
>1	4/2 (1/0)	6.28	1.08,36.6*	6.89	1.18, 40.3*	2/1 (1/0)	6.66	0.55, 80.4	7.32	0.59, 90.9	2/1 (2/0)	5.05	0.41, 62.7	5.27	0.42, 65.5
Traffic accident‐related
Once only	14/25 (4/4)	1.16	0.58, 2.33	1.13	0.56, 2.27	9/13 (4/4)	1.25	0.50, 3.16	1.22	0.48, 3.12	5/12 (4/4)	1.06	0.35, 3.21	1.01	0.33, 3.09
>1	3/2 (1/0)	3.73	0.59, 23.8	3.49	0.54, 22.4	1/2 (0/1)	1.65	0.14, 20.1	1.64	0.13, 20.2	2/0 (2/0)	—	—	—	—
Other circumstances
Once only	5/14 (2/2)	0.70	0.24, 2.03	0.70	0.24, 2.03	3/8 (1/2)	0.62	0.16, 2.44	0.6	0.15, 2.39	2/6 (2/2)	0.76	0.14, 4.14	0.76	0.14, 4.23
>1	1/0 (0/0)	—	—	—	—	0/0 (0/0)	—	—	—	—	1/0 (1/0)	—	—	—	—
Multiple circumstances ª
>1	17/12 (5/2)	2.69	1.22, 5.92*	2.48	1.12, 5.50*	15/10 (7/3)	2.32	0.98, 5.52	2.15	0.90, 5.14	2/2 (2/1)	3.67	0.45, 29.8	3.43	0.41, 29.0

OR adjusted age, gender (for analyses combining males and females), education, ethnicity, socioeconomic status (SES), smoking, alcohol consumption.

OR¹ adjusted age, gender (for analyses combining males and females), education, ethnicity, socioeconomic status (SES), smoking, alcohol consumption, sport, spine injury & emotional trauma.

Abbreviations: CI, confidence interval; OR, odds ratio.

^ªMultiple events: participants who had more than one type of circumstance of head injury.

^* p < .05.