Study design and study population
allergic disease
RECRUITMENT
In the present study, we analyzed dietary data from infants in the PreventADALL RCT, a multicenter, prospective, general, population-based mother–child birth cohort, aiming at primary prevention of allergic disease. Study design, recruitment, inclusion criteria, and baseline characteristics are described in detail elsewhere [Newborns were randomly assigned to 4 intervention groups: no intervention (control group), skin intervention, food intervention, or the combined interventions [The PreventADALL study was approved by the Regional Committee for Medical and Health Research Ethics in South-Eastern Norway (2014/518) and in Stockholm, Sweden (2014/2242-31/4). The study was registered at Dietary data were obtained through electronic weekly diaries (2–26 wk of age) and questionnaires (at 3, 6, 9, and 12 mo of age). Breastfeeding was assessed at 3, 6, 9, and 12 mo of age by parents reporting for the last 3 mo if the infant had received breastmilk and the time of breastfeeding cessation. If the infant was not exclusively breastfed, the amount of breastmilk consumed was categorized as most of the diet, the same amount as other food, or as a small part of the diet. At 6 mo, parents reported the amount of breastmilk consumed as no breastmilk, a small part of the diet, approximately half of the diet, or most of the diet. Consumption of porridge, how often it was given, at what age it was first introduced, and what it was made of (rice, millet, oat, corn, wheat, whole meal, spelt, Sinlac, and other types) was reported at 3 and 6 mo. Questions about dairy intake at 6, 9, and 12 mo included the time of first introduction and what kind of dairy products were given to the infant. At 6, 9, and 12 mo, parents were asked to indicate how often the infant consumed several solid foods. The categories included: bread/cookies/waffles/cakes and other baked goods, fruit or berries, root vegetables (such as potato, turnip, carrot, and parsnip), other vegetables, peanut (as a spread or incorporated in other foods), pure egg (eg, fried, cooked, scrambled, and eggnog), egg in other foods (eg, gratin, waffles, baked goods, paste, or similar), fatty fish (salmon, trout, mackerel, pike, halibut, and eel), other fish, shellfish, poultry meat, and other meat. We also asked about how much of the infant food was home cooked compared with commercially prepared (industrially processed), as well as the content of organic food in the infant’s diet.All questions about diet were mandatory, assuring a complete set of values in all questionnaires. Please see the Supplementary data section and 