Effect of long term consumption of probiotic milk on infections in children attending day care centres: double blind, randomised trial

Abstract

Objective: To examine whether long term consumption of a probiotic milk could reduce gastrointestinal and respiratory infections in children in day care centres. Design: Randomised, double blind, placebo controlled study over seven months. Setting: 18 day care centres in Helsinki, Finland. Participants: 571 healthy children aged 1-6 years: 282 (mean (SD) age 4.6 (1.5) years) in the intervention group and 289 (mean (SD) age 4.4 (1.5) years) in the control group. Intervention: Milk with or without Lactobacillus GG. Average daily consumption of milk in both groups was 260 ml. Main outcome measures: Number of days with respiratory and gastrointestinal symptoms, absences from day care because of illness, respiratory tract infections diagnosed by a doctor, and course of antibiotics. Results: Children in the Lactobacillus group had fewer days of absence from day care because of illness (4.9 (95% confidence interval 4.4 to 5.5) v 5.8 (5.3 to 6.4) days, 16% difference, P=0.03; age adjusted 5.1 (4.6 to 5.6) v 5.7 (5.2 to 6.3) days, 11% difference, P=0.09). There was also a relative reduction of 17% in the number of children suffering from respiratory infections with complications and lower respiratory tract infections (unadjusted absolute % reduction −8.6 (−17.2 to −0.1), P=0.05; age adjusted odds ratio 0.75 (0.52 to 1.09), P=0.13) and a 19% relative reduction in antibiotic treatments for respiratory infection (unadjusted absolute % reduction −9.6 (−18.2 to −1.0), P=0.03; adjusted odds ratio 0.72 (0.50 to 1.03), P=0.08) in the Lactobacillus group. Conclusions: Lactobacillus GG may reduce respiratory infections and their severity among children in day care. The effects of the probiotic Lactobacillus GG were modest but consistently in the same direction. What is already known on this topic: Children attending day care centres are at high risk of respiratory and gastrointestinal infection The successful prevention of respiratory infections could be extremely useful for families and for society in general Short term use of probiotic bacteria has been shown to reduce the severity of rotavirus diarrhoea and the incidence of diarrhoea associated with the use of antibiotics What this study adds: In a double blind, randomised, long term study milk containing Lactobacillus GG slightly reduced the incidence of respiratory infections and antibiotic treatment in children