Contemporary meta-analysis of short-term probiotic consumption on gastrointestinal transit

Table 5 Subgroup analysis of study- and subject-related factors on intestinal transit time

Study	SMD	95%CI	P value	P value
			(pre-post)	(between groups)
Subject condition
Constipation/IBS-C (n = 9)	0.57	0.39 to 0.75	< 0.001	< 0.01
Healthy (n = 8)	0.22	0.05 to 0.39	0.01
Study quality
Jadad score ≥ 3 (n = 12)	0.45	0.31 to 0.59	< 0.001	0.01
Jadad score < 3 (n = 5)	0.00	-0.33 to 0.33	> 0.99
Age1
≥ 39 yr (n = 9)	0.51	0.29 to 0.73	< 0.001	0.08
< 39 yr (n = 8)	0.27	0.09 to 0.44	< 0.01
Publication year
After 2008 (n = 10)	0.47	0.29 to 0.65	< 0.001	0.08
Before 2008 (n = 7)	0.20	-0.03 to 0.44	0.09
Number of probiotic strains
Single strain (n = 10)	0.49	0.32 to 0.66	< 0.001	0.09
Multiple strains (n = 7)	0.23	-0.01 to 0.47	0.06
Study design
Parallel groups (n = 11)	0.48	0.31 to 0.65	< 0.001	0.09
Cross-over (n = 6)	0.26	-0.02 to 0.46	0.07
Body mass index12
≥ 25 kg/m2 (n = 5)	0.59	0.24 to 0.94	< 0.001	0.16
< 25 kg/m2 (n = 7)	0.31	0.13 to 0.49	< 0.001
Treatment duration1
< 18 d (n = 8)	0.45	0.29 to 0.60	< 0.001	0.17
≥ 18 d (n = 9)	0.22	-0.06 to 0.50	0.12
Geographic location
Americas (n = 6)	0.47	0.26 to 0.67	< 0.001	0.20
Europe (n = 11)	0.28	0.07 to 0.49	< 0.01
Female gender proportion1
≥ 86% (n = 9)	0.47	0.30 to 0.64	< 0.01	0.22
< 86% (n = 8)	0.27	0.00 to 0.54	< 0.05
Confounding treatments3
Yes (n = 7)	0.46	0.24 to 0.67	< 0.001	0.32
No (n = 10)	0.30	0.10 to 0.51	< 0.01
Daily probiotic dosage1
≥ 1.610 CFU (n = 8)	0.40	0.12 to 0.67	< 0.01	0.74
< 1.610 CFU (n = 7)	0.34	0.16 to 0.52	< 0.001

¹Categorized by median value;

²Body mass index not reported for 5 treatment effects;

³Includes studies where treatment included probiotics plus fiber or non-digestible sugar. Variables sorted from lowest to highest between-groups P value; n represents the number of treatment effects. IBS-C: Irritable bowel syndrome, constipation predominant; SMD: Standardized mean difference.