TABLE 2.

Amyotrophic lateral sclerosis smoothed incidence in different municipalities according to the percentage of area covered by a specific crop.

Crops (% area covered in municipalities by each specific crop)	Municipalities (N)	Median ALS incidence (IQR)	p §	Mean ALS incidence (SD)	p*
Arable crops
0%	13	0.75 (0.00–1.26)	<0.001	1.32 (2.04)	0.001
0%–10%	423	0.79 (0.16–2.50)		1.88 (2.45)
10%–20%	223	0.93 (0.23–3.00)		2.06 (2.51)
20%–30%	134	1.21 (0.47–3.00)		2.32 (2.58)
30%–40%	122	1.25 (0.39–4.10)		2.50 (2.68)
40%–50%	156	1.65 (0.57–4.25)		2.59 (2.45)
> 60%	110	1.81 (0.75–4.11)		2.70 (2.51)
Vineyards
0%	434	0.81 (0.22–3.00)	<0.001	1.99 (2.49)	0.274
0%–10%	631	1.34 (0.46–3.42)		2.43 (2.57)
>10%	116	0.75 (0.19–2.28)		1.67 (2.14)
Meadows
0%	771	1.22 (0.44–3.21)	<0.001	2.29 (2.52)	0.289
0%–10%	261	1.06 (0.31–3.00)		2.11 (2.46)
>10%	149	0.53 (0.15–2.34)		1.81 (2.59)
Orchards
0%	706	1.16 (0.40–3.20)	0.027	2.30 (2.58)	0.537
>0%	475	1.00 (0.28–3.00)		2.04 (2.42)
Vegetable crops
0%	821	1.24 (0.44–3.23)	<0.001	2.33 (2.56)	0.569
>0%	360	0.83 (0.21–2.66)		1.88 (2.40)
Paddy fields
0%	1064	1.11 (0.34–3.00)	0.110	2.21 (2.51)	0.527
>0%	117	0.88 (0.24–2.71)		2.03 (2.55)
Nurseries
0%	1057	1.06 (0.31–3.00)	0.018	2.14 (2.48)	0.430
>0%	124	1.45 (0.40–4.31)		2.67 (2.80)
Total	1181

Note: Municipalities were grouped differently in order to have a significant number of municipalities for each group. p ^§, Kruskal–Wallis test and Mann–Whitney U test; p*, linear regression analysis performed using mean incidence in municipalities grouped by increasing percentage of each agricultural area. Significant results (p < 0.05) are in bold type.

Abbreviations: ALS, amyotrophic lateral sclerosis; IQR, interquartile range; SD, standard deviation.