4.1. Colostrum Reduces URTI Frequency and Severity
AGS, ’ reduction, URTIs, ’
Our two main measures of colostrum effectiveness in the prevention of URTIs were the frequency of symptomatic days (FSDs) and the URTI symptoms’ average gravity score (AGS). The information on URTI symptoms’ appearance was self-reported by parents and guardians based on a gravity scale named the URTI score (grades 0–3; see Materials and Methods).For the first primary outcome, the FSD, we summed up all days reported with any symptoms (no matter the gravity level) and used the sum to calculate the frequency of days with URTIs within particular periods of the experiment. By the 20th week of the trial, we observed a statistically significant reduction in the FSD median by a third in the COL as compared to the PBO group. The analyses of the periods between the beginning of supplementation and weeks 4, 8, 12, 14, 16, 18, 20 and 21 revealed that the colostrum supplementation started to exert its significant protective impact on the appearance of days with URTI symptoms no earlier than by the week 8. This protective effect was then observed at week 12, as well as weeks 16, 18 and 20, while at weeks 14 and 21, the results were borderline significant (Our second primary outcome was the AGS of URTI symptoms. The statistically significant reduction in AGS medians was observed in the COL vs. the PBO group when the period from beginning of supplementation until week 20 was assessed. The repeated measures of periods ending at weeks 4, 8, 12, 14, 16 and 18 also consistently showed a significant result in this regard, while the borderline significance was found at week 21 (When AGS medians’ reduction induced by colostrum supplementation is confronted with FSD results, a more consistent statistically significant difference in favor of the COL group over all analyzed periods is observed. Especially striking is the difference observed in AGS in the period ending at week 4, while there is no such difference for FSD, thus suggesting the earlier development of a protective effect against the gravity versus frequency of URTIs. The outcome medians’ reduction rate also favors the gravity reduction, ranging between 33% and 45% for AGS, while for FSD, this range is just from 30% to 37%. While it has not been confirmed by any test, the above-presented reasoning allows us to assume that even if URTIs develop in colostrum-protected children, they seem to have a milder course. However, more studies are needed to verify this notion.