Brief Article
Copyright ©2013 Baishideng Publishing Group Co.
World J Gastroenterol. Aug 7, 2013; 19(29): 4718-4725
Published online Aug 7, 2013. doi: 10.3748/wjg.v19.i29.4718
Table 1 Study characteristics
Ref.Study designActive: control (n:n)Transit timeoutcome, methodProbiotic strainDaily dosage(109 cfu)Delivery methodTreatmentduration (d)
Agrawal et al[14]Parallel groups17:17CTT, radiopaque markersB. lactis DN-173 01025.0Active: Yogurt + probioticControl: Nonfermented milk-based product28
Bartram et al[15]Cross-over12OATT, radiopaque markersB. longum  > 0.5Active: Yogurt with 2.5 g lactulose + probioticControl: Yogurt21
Bouvier et al[16]Parallel groups36:36CTT, radiopaque markersB. lactis DN-173 01097.5Active: Probiotic fermented milkControl: Heat-treated probiotic fermented milk11
Holma et al[17]Parallel groups12:10TITT, radiopaque markersL. rhamnosus GG20Active: Buttermilk + probiotic and white wheat breadControl: White wheat bread21
Hongisto et al[18]Parallel groups16:14TITT, radiopaque markersL. rhamnosus GG15Active: Yogurt + probiotic and low fiber toastControl: Low fiber toast21
Malpeli et al[19]Cross-over83OCTT, carmine red dyeB. lactis BB12L. casei CRL 4312-20 2-12Active: Yogurt with 0.625 g inulin and oligofructose + probioticControl: Yogurt15
Marteau et al[20]Cross-over32CTT, radiopaque markersB. lactis DN-173 01018.75Active: Yogurt + probioticControl: Yogurt10
Rosenfeldt et al[21]Cross-over13GTT, radiopaque markersL. rhamnosus 19070-2,L. reuteri DSM 1224620 20Active: Freeze-dried powder + probioticControl: Skimmed milk powder w/dextrose18
Rosenfeldt et al[21]Cross-over13GTT, radiopaque markersL. casei subsp. alactus CHCC 3137,L. delbrueckii subsp. lactis CHCC 2329,L. rhamnosus GG20 20 20Active: Freeze-dried powder + probioticControl: Skimmed milk powder w/dextrose18
Sairanen et al[22]Parallel groups22:20CTT, radiopaque markersB. longum BB536, B. lactis 420,L. acidophilus 1452.4-181 0.48Active: Probiotic fermented milkControl: Fermented milk21
Waller et al[23]Parallel groups33:34WGTT; radiopaque markersB. lactis HN0191.8Active: Capsule, maltodextrin, probioticControl: Capsule, maltodextrin14
Waller et al[23]Parallel groups33:34WGTT; radiopaque markersB. lactis HN01917.2Active: Capsule, maltodextrin, probioticControl: Capsule, maltodextrin14
Krammer et al[24]Parallel groups12:12CTT, radiopaque markersL. casei Shirota6.5Active: Probiotic fermented milk drinkControl: Nonfermented milk drink28
Table 2 Subject characteristics
Ref.Age (yr)Female genderBMI (kg/m2)Condition
Agrawal et al[14]40100%25IBS-C
Bartram et al[15]2358%-None
Bouvier et al[16]3350%22None
Holma et al[17]4492%124Constipation
Hongisto et al[18]43100%24Constipation
Malpeli et al[19]41100%-Constipation
Marteau et al[20]27100%21None
Rosenfeldt et al[21]250%-None
Rosenfeldt et al[21]250%-None
Sairanen et al[22]3964%25None
Waller et al[23]4465%31Constipation
Waller et al[23]4465%32Constipation
Krammer et al[24]50100%-Constipation
Table 3 Assessment of study quality
Ref.Jadad scale
Randomization(range: 0-2)Double blinding(range: 0-2)Subject account(range: 0-1)Total score1(range: 0-5)
Agrawal et al[14]1214
Bartram et al[15]1203
Bouvier et al[16]1203
Holma et al[17]  1012
Hongisto et al[18]1001
Malpeli et al[19]0213
Marteau et al[20] 1214
Rosenfeldt et al[21]1102
Rosenfeldt et al[21]1102
Sairanen et al[22]1102
Waller et al[23]2215
Waller et al[23]2215
Krammer et al[24]1113
Table 4 Meta-regression of study- and subject-related factors on intestinal transit time
VariableUnit of measureInterceptPoint estimateExplained varianceP-value
Constipation0 = no, 1 = yes0.1710.41539%0.01
AgePer 10 years-0.4450.23027%0.03
Female gender proportionPer 10%0.0240.05323%< 0.05
Body mass index1Per 5 kg/m2-0.5440.20025%0.11
Daily probiotic dosagePer 10 × 109 cfu0.454-0.0131%0.62
Treatment durationPer 1 wk0.535-0.0481%0.67
Table 5 Subgroup analysis of study- and subject-related factors on intestinal transit time
StudySMD95%CIP-value(within groups)P-value(between groups)
Subject condition
Constipation/IBS-C (n = 7)0.590.39-0.79< 0.0010.01
Healthy (n = 6)0.17-0.08-0.420.18
≥ 40 years (n = 7)0.590.39-0.79< 0.0010.01
< 40 years (n = 6)0.17-0.08-0.420.18
Study design
Parallel groups (n = 8)0.490.24-0.75< 0.0010.23
Cross-over (n = 5)0.25-0.06-0.560.11
Body mass index1
≥ 25 kg/m2 (n = 4)0.610.27-0.95< 0.0010.29
< 25 kg/m2 (n = 4)0.34-0.02-0.700.06
Female gender proportion
≥ 75% (n = 6)0.440.17-0.76< 0.010.47
< 75% (n = 7)0.320.05-0.600.02
Treatment duration
< 20 d (n = 7)0.430.18-0.67< 0.0010.62
≥ 20 d (n = 6)0.32-0.02-0.660.07
Daily probiotic dosage
≥ 1010 cfu (n = 8)0.410.14-0.68< 0.010.84
< 1010 cfu (n = 5)0.360.05-0.680.02
Table 6 Subgroup analysis of probiotic strains on intestinal transit time
Probiotic strainTreatment effects (n)SMD95%CIP-value
B. lactis HN01920.720.27-1.18< 0.01
B. lactis DN-173 01030.540.15-0.94< 0.01
L. rhamnosus GG20.25-0.38-0.870.44
Other single strains20.23-0.41-0.870.48
Strain combinations40.17-0.18-0.520.34
Table 7 Sample size requirements for randomized controlled trials based on standardized mean difference
SMDStudy design
Parallel groups1Cross-over