Table 4.

Stratified analyses of associations between ever exposure to crude oil/oily water and acute neurological symptoms, compared to never exposure, estimated by adjusted prevalence ratios (PRs) and 95% confidence intervals (CIs).

Neurologic symptom	N^a	N^b	PR (adj.)^c	95%CI	N^a	N^b	PR (adj.)^c	95%CI	Interaction p-value
	Males				Females
Headaches	1538	2589	1.87	(1.69–2.07)	353	375	1.34	(1.14–1.58)	< 0.01
Lightheadedness/dizziness	507	3620	3.00	(2.37–3.80)	136	507	2.07	(1.44–2.96)	0.02
Difficulty concentrating	372	3755	1.81	(1.44–2.26)	96	632	1.28	(0.86–1.90)	0.01
Numbness or tingling sensations	193	3934	2.41	(1.68–3.42)	36	692	1.82	(0.88–3.80)	0.30
Blurred/double vision	175	3952	1.96	(1.38–2.78)	43	685	1.31	(0.69–2.49)	0.05
Memory loss/confusion	109	4018	2.58	(1.60–4.16)	18	710	1.03	(0.37–2.87)	0.02
	With exhaust exposure				Without exhaust exposure
Headaches	1649	2011	1.39	(1.27–1.52)	242	953	1.86	(1.51–2.29)	< 0.01
Lightheadedness/dizziness	586	3074	2.23	(1.80–2.77)	57	1138	2.30	(1.32–4.02)	0.88
Difficulty concentrating	403	3257	1.32	(1.09–1.68)	65	1130	1.29	(0.71–2.33)	0.92
Numbness or tingling sensations	206	3454	1.68	(1.20–2.37)	23	1172	3.48	(1.44–8.42)	0.21
Blurred/double vision	181	3479	1.63	(1.15–2.33)	37	1158	1.26	(0.54–2.92)	0.68
Memory loss/confusion	112	3548	1.78	(1.11–2.86)	15	1180	2.04	(0.56–7.41)	0.74
			With oil-PPE				Without oil-PPE
Headaches	1379	1756	1.71	(1.53–1.92)	512	1208	1.45	(1.25–1.68)	0.14
Lightheadedness/dizziness	501	2634	2.59	(2.01–3.35)	142	1578	2.50	(1.79–3.48)	0.94
Difficulty concentrating	307	2828	1.71	(1.30–2.25)	161	1559	1.50	(1.10–2.06)	0.60
Numbness or tingling sensations	164	2971	3.06	(1.87–5.00)	65	1655	1.37	(0.82–2.28)	0.06
Blurred/double vision	147	2988	2.45	(1.54–3.91)	71	1649	1.15	(0.68–1.96)	0.02
Memory loss/confusion	89	3046	2.55	(1.35–4.81)	38	1682	1.72	(0.88–3.36)	0.22
	Pre-capping				Post-capping
Headaches	547	952	1.80	(1.62–2.00)	1344	2012	1.54	(1.33–1.77)	0.09
Lightheadedness/dizziness	155	1344	2.35	(1.87–2.96)	488	2868	3.30	(2.27–4.79)	0.25
Difficulty concentrating	129	1370	1.61	(1.27–2.03)	339	3017	1.66	(1.17–2.35)	0.90
Numbness or tingling sensations	59	1440	2.38	(1.63–3.47)	170	3186	1.73	(0.97–3.08)	0.95
Blurred/double vision	55	1444	1.82	(1.27–2.61)	163	3193	1.40	(0.80–2.45)	0.52
Memory loss/confusion	35	1464	1.55	(0.96–2.52)	92	3264	5.09	(2.29–11.30)	0.07
	Low heat				High heat
Headaches	825	1573	1.65	1.48–1.84	1066	1391	1.73	1.50–1.99	0.09
Lightheadedness/dizziness	220	2178	2.18	1.68–2.82	423	2034	3.22	2.29–4.54	0.01
Difficulty concentrating	261	2137	1.49	1.19–1.86	207	2250	1.99	1.30–3.06	0.45
Numbness or tingling sensations	106	2292	2.12	1.45–3.10	123	2334	2.34	1.29–4.24	0.80
Blurred/double vision	115	2283	1.43	1.00–2.07	103	2354	3.13	1.51–6.46	0.02
Memory loss/confusion	67	2331	2.00	1.24–3.22	60	2397	2.43	0.97–6.13	0.45

Count of responders reporting the symptom for the corresponding exposure level.

Count of responders not reporting the symptom for the corresponding exposure level.

Adjusted for: age, sex, dispersant contact, exhaust exposure, smoking, environmental heat and hours of sleep per night during deployment; note each model is adjusted for all of these co-variates, with the exception of what they are stratified by.