The use of self-reported symptoms as a proxy for acute organophosphate poisoning after exposure to chlorpyrifos 50% plus cypermethrin 5% among Nepali farmers: a randomized, double-blind, placebo-controlled, crossover study

Table 4 Results of the outcome measures for the organophosphate spray session (OP) and the placebo spray session (PL)

Variable	OP (n = 42)		PL (n = 42)		P value*
Variable	Baseline	Follow up	Baseline	Follow up	P value*
PchE activity (U/mL)
Mean (SD)	1.58 (0.41)	1.60 (0.40)	1.58 (0.42)	1.60 (0.41)	0.775^a
Symptoms
Sum of all symptoms	42	41	31	40	0.378^b
Number of symptoms per farmer, n (%)
0	22 (52.4)	23 (54.8)	27 (64.3)	21 (50.0)
1	11 (26.2)	10 (23.8)	6 (14.3)	10 (23.8)
2	5 (11.9)	3 (7.1)	6 (14.3)	5 (11.9)
≥ 3	4 (9.5)	6 (14.3)	3 (7.1)	6 (14.3)
Distribution, n (%)
Headache	6 (14.3)	10 (23.8)	4 (9.5)	10 (23.8)
Dizziness	1 (2.4)	1 (2.4)	2 (4.8)	6 (14.3)
Skin irritation	7 (16.7)	9 (21.4)	3 (7.1)	10 (23.8)
Extreme tiredness	4 (9.5)	5 (11.9)	6 (14.3)	5 (11.9)
Weakness	6 (14.3)	3 (7.1)	4 (9.5)	2 (4.8)
Anxiety	3 (7.1)	1 (2.4)	0 (0.0)	1 (2.4)
Excessive sweating	5 (11.9)	4 (9.5)	1 (2.4)	0 (0.0)
Trembling hands	1 (2.4)	1 (2.4)	1 (2.4)	1 (2.4)
Vomiting	0 (0.0)	0 (0.0)	1 (2.4)	0 (0.0)
Diarrhea	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)
Abdominal pain	1 (2.4)	2 (4.8)	1 (2.4)	1 (2.4)
Blurred vision	4 (9.5)	1 (2.4)	3 (7.1)	4 (9.5)
Paralysis	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)
Salivation	1 (2.4)	1 (2.4)	1 (2.4)	0 (0.0)
Tearing	0 (0.0)	0 (0.0)	2 (4.8)	0 (0.0)
Lack of coordination	0 (0.0)	1 (2.4)	0 (0.0)	0 (0.0)
Respiratory difficulties	3 (7.1)	2 (4.8)	2 (4.8)	0 (0.0)
Confusion	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)

* = For difference between the organophosphate spray session and the placebo spray session
^a = Two sample t-test
^b = Mann Whitney U-test