Table 1.- Variants (SNPs) included in the PRS calculation
(Disease/Trait: diarrhoeal_disease_at_age_1)
rsID	Risk allele	Effect size
rs35106244	TRUE	0.239
Effect size: LN(OR)

Table 2.- PRS Score distribution among populations and regions
(Disease/Trait: diarrhoeal_disease_at_age_1)
	count	mean	sd	se	lower.ci	upper.ci
Pyrenean regions
WEST	168	0.097	0.084	0.007	0.085	0.110
SOUTH	83	0.118	0.080	0.009	0.101	0.136
EAST	146	0.103	0.083	0.007	0.090	0.117
Populations
IBS	107	0.088	0.086	0.008	0.072	0.105
PIR	397	0.104	0.083	0.004	0.096	0.112

Table 3.- Pairwise t-test for PRS score among populations and regions
(Disease/Trait: diarrhoeal_disease_at_age_1)
group1	group2	n1	n2	p	p.signif	p.adj	p.adj.signif
IBS	PIR	107	397	0.0855	ns	0.855	ns
IBS	WEST	107	168	0.3710	ns	1.000	ns
IBS	SOUTH	107	83	0.0145	*	0.145	ns
IBS	EAST	107	146	0.1600	ns	1.000	ns
WEST	SOUTH	168	83	0.0655	ns	0.655	ns
WEST	EAST	168	146	0.5470	ns	1.000	ns
SOUTH	EAST	83	146	0.1930	ns	1.000	ns
* p < .05, ** p < .01, *** p < .001

Table 4.- Chi-square test comparison of percentile counts on Pyrenean regions compared to Iberian peninsula population
(Disease/Trait: diarrhoeal_disease_at_age_1)
Percentile rank	PIR				WEST				SOUTH				EAST
	adj.std.val	p.value	sig.val		adj.std.val	p.value	sig.val		adj.std.val	p.value	sig.val		adj.std.val	p.value	sig.val
pct95	0.000	1.000	.	white	0.000	1.000	.	white	0.000	1.000	.	white	0.000	1.000	.	white
pct75.95	1.020	0.308	.	white	0.300	0.764	.	white	1.020	0.308	.	white	0.400	0.689	.	white
pct50.75	0.000	1.000	.	white	0.000	1.000	.	white	0.000	1.000	.	white	0.000	1.000	.	white
pct25.50	1.830	0.067	.	white	0.810	0.418	.	white	1.830	0.067	.	white	1.360	0.174	.	white
pct25	−2.770	0.006	**		−1.060	0.289	.	white	−2.770	0.006	**		−1.730	0.084	.	white
adj.std.val: Adjusted standardized residuals value; p.value: P value; sig.val: statistical significance, * p < .05, ** p < .01, *** p < .001; red dash to bottom: lower counts than reference; green dash to up: upper counts than reference