Age 0 - 12 months

PROBIT Home | 0 - 12 months | 6.5 years | 11.5 yrs | 16 yrs | Publications | Collaborate

June 1996 - December 1997

During the birth hospitalization, study obstetricians collected information from mothers on background and birth characteristics. At 1, 2, 3, 6, 9 and 12 months of age, study pediatricians assessed participants’ growth and collected clinical data from polyclinic records.

Intention to treat analyses of PROBIT I data demonstrated that the randomized intervention produced higher rates of breastfeeding exclusivity and duration; infants at the intervention sites were significantly more likely to be exclusively breastfed at 3 months (43.3% vs. 6.4%, p<0.001) and at 6 months (7.9% versus 0.6%, p=0.01) when compared to infants at the control sites.  Infants at the intervention sites were also less likely to have 1 or more gastrointestinal tract infections (9.1% vs. 13.2%; adjusted OR, 0.60; 95% CI, 0.40-0.91) or atopic eczema (3.3% vs 6.3%; adjusted OR, 0.54; 05% CI, 0.31-0.95) in their first year of life (Kramer et al, JAMA 2001).  There were no demonstrable adverse effects associated with exclusive breastfeeding for 6 months (Kramer et al, Am J Clin Nutr, 2003).  In case control studies nested within the larger PROBIT study, we examined the hypothesis that prior gastrointestinal infection could protect against atopic eczema or wheeze among infants; we found no evidence to support this hypothesis (Kramer et al, Clin Exp Allergy, 2004).

Between May 2017-December 2019, we collected additional information to supplement the data collected in previous iterations of PROBIT, and to facilitate contact with the PROBIT mothers and participants for future research opportunities.  Study pediatricians contacted the PROBIT mothers and participants to request:

  • Their updated mailing addresses, telephone numbers and email addresses;
  • Participants only: their 9- and 11-year national examination scores, as an additional, nationally standardized measure of cognitive ability;
  • Mothers only: permission for the pediatricians to abstract data from their maternity hospital obstetric records obtained during the pregnancy of the PROBIT child.

In total, pediatricians contacted 11,285 (66.2% of the original 17,046) PROBIT participants and 13,208 (77.5%) PROBIT mothers and abstracted 12,630 (74.1%) maternal delivery records.

Analyses of the most recent data collected are in progress.

Principal Investigators

1996 - 1997
Michael Kramer, MD: McGill University, Quebec, Canada

2017 - 2019
Michael Kramer, MD: McGill University, Quebec, Canada


1996 - 1997
Belarus: Zinaida Sevkovskaya, MD; Irina Dzikovich, MD, PhD; Irina Vanilovich, MD; Vyacheslav Zubovich, MD, PhD; Dimitri Mknuik, MD, PhD; Elena Gluchanina, MD; Viktor Dombrovskiy, MD, PhD; Anatoly Ustinovitch, MD, PhD; Tamara Kot, MD; Natalia Bogdanovich, MD, PhD; Lydia Ovchinikova, RN

2017 - 2019
Belarus: Konstantin Vilchuck, MD; Natalia Bogdanovich, MD

1996 - 1997 Study Documents

2017 - 2019 Study Documents

Selected Publications