In particular, breastfeeding may be of concern because it has been shown to be associated with both child's use of antibiotics36, 37 and cow's milk
allergy, although inconsistently so.38
In a
large Finnish birth
cohort, the median durations of exclusive and total breastfeeding were 1.4 months and 7.0 months, respectively, and the proportion of breastfed infants decreased from 95 % at the age of 1 month to 58 % at the age of 6 months.39 Another limitation is our reliance on pharmacy records, which provides only a rough estimation of drug use.
In the
large cohort study mentioned above, the most common
allergy was peanut with a prevalence of 2.6 %, followed by milk at 2.2 %, egg at 1.8 %, shellfish at 1.5 % and soy at 0.7 %.