Probiotics and Infections in Conscripts in Military Service

Probiotic and Respiratory and Gastrointestinal Tract Infections in Finnish Military Conscripts - a Randomized and Placebo-controlled Double-blinded Study

The aim was to study whether probiotic intervention has an impact on seasonal occurrence of upper respiratory and gastrointestinal infections in two different conscript groups. In a randomised, double-blinded, placebo controlled study a total of 983 healthy adults were enrolled from two intakes of conscripts. Conscripts were randomised to receive either a probiotic combination of Lactobacillus rhamnosus GG (LGG) and Bifidobacterium animalis ssp. lactis BB12 (BB12) or a control chewing tablet twice daily for 150 days (recruits) or for 90 days (reserve officer candidates). Clinical examinations were carried out and daily symptom diaries were collected. Outcome measures were the number of days with respiratory and gastrointestinal symptoms and symptom incidence, number and duration of infection episodes, number of antibiotic treatments received and number of days out of service because of the infection. Statistically no significant differences were found between the intervention groups either in the risk of symptom incidence or duration. However, probiotic intervention was associated with reduction of specific respiratory infection symptoms in military recruits, but not in reserve officer candidates. Probiotics did not significantly reduce overall respiratory and gastrointestinal infection morbidity.

Military conscripts are susceptible to respiratory and gastrointestinal tract infections. In previous studies probiotics have shown potency to reduce upper respiratory and gastrointestinal infections. The aim was to study whether probiotic intervention has an impact on seasonal occurrence of upper respiratory and gastrointestinal infections in two different conscript groups. In a randomised, double-blinded, placebo controlled study a total of 983 healthy adults were enrolled from two intakes of conscripts. Conscripts were randomised to receive either a probiotic combination of Lactobacillus rhamnosus GG (LGG) and Bifidobacterium animalis ssp. lactis BB12 (BB12) or a control chewing tablet twice daily for 150 days (recruits) or for 90 days (reserve officer candidates). Clinical examinations were carried out and daily symptom diaries were collected. Outcome measures were the number of days with respiratory and gastrointestinal symptoms and symptom incidence, number and duration of infection episodes, number of antibiotic treatments received and number of days out of service because of the infection. Statistically no significant differences were found between the intervention groups either in the risk of symptom incidence or duration. However, probiotic intervention was associated with reduction of specific respiratory infection symptoms in military recruits, but not in reserve officer candidates. Probiotics did not significantly reduce overall respiratory and gastrointestinal infection morbidity.

The number of sick days with respiratory and gastrointestinal symptoms and symptom incidence. Other outcome measures were the number and duration of infection episodes, the number of antibiotic treatments received, and the number of days out of service due to an infection. Respiratory infection episodes and symptomatic days were counted by the basis of respiratory infection symptoms recorded into the symptom diary and from the medical visits to health care centers. If the conscript showed minimum of two RTI symptoms for a period of one day or one RTI symptom for a period of two days a RTI episode was considered to be present. Between two episodes a minimum of seven days of non-symptomatic period should be experienced if to be considered as two separate infections. If there were less non-symptomatic days, it was considered to be a continuation of the same infection episode. Symptomatic days were days when at least one symptom was experienced.

Respiratory infection episodes and symptomatic days were counted by the basis of respiratory infection symptoms recorded into the symptom diary and from the medical visits to health care centers.

If the conscript showed minimum of two RTI symptoms for a period of one day or one RTI symptom for a period of two days a RTI episode was considered to be present. Between two episodes a minimum of seven days of non-symptomatic period should be experienced if to be considered as two separate infections. If there were less non-symptomatic days, it was considered to be a continuation of the same infection episode. Symptomatic days were days when at least one symptom was experienced. Gastrointestinal tract infection episodes and symptom days were calculated in the same fashion except 14 non symptomatic days should be in between the two to be considered as two different episodes.

Inclusion Criteria: Healthy adults attending military service in July 2012 and healthy adults attending reserve office school in October 2012 Exclusion Criteria: Regular use of oral corticosteroids Regular consumption (over 3 times a week) of probiotic bacteria containing products 3 weeks before intervention

Kalima K, Lehtoranta L, He L, Pitkaniemi J, Lundell R, Julkunen I, Roivainen M, Narkio M, Makela MJ, Siitonen S, Korpela R, Pitkaranta A. Probiotics and respiratory and gastrointestinal tract infections in Finnish military conscripts - a randomised placebo-controlled double-blinded study. Benef Microbes. 2016 Sep;7(4):463-71. doi: 10.3920/BM2015.0172. Epub 2016 Apr 6.