Extract and molecular-based early infant sensitization and associated factors-A PreventADALL study.

BACKGROUND: More knowledge about sensitization patterns in early infancy, including impact of molecular allergology, is needed to help predict future allergy development more accurately. OBJECTIVE: We aimed to determine the prevalence and patterns of allergic sensitization at 3 months of age, and explore possible associated factors. METHODS: From the Scandinavian antenatally recruited PreventADALL mother-child cohort, we included 1110 3-month infants with available serum. Sensitization was defined as s-IgE of ≥0.1 kUA /L by Phadiatop Infant® (ThermoFisher Scientific) including birch, cat, grass, dog, milk, egg, peanut and wheat. Further ImmunoCAP analyses to ovomucoid, casein, Ara h 1-3, omega-5-gliadin were performed in food extract s-IgE-positive children. Maternal sensitization was defined as s-IgE ≥ 0.35 kUA /L to Phadiatop® (inhalant allergen mix) and/or Fx5 (food allergen mix) at 18-week pregnancy. RESULTS: Overall 79 (7.3%) infants had specific sensitization, many with low s-IgE-levels (IQR 0.16-0.81 kUA /L), with 78 being sensitized to food extract allergens; 41 to egg, 27 to milk, 10 to peanut, and 25 to wheat. A total of 62/78 were further analysed, 18 (29%) had s-IgE to ovomucoid, casein, Ara h 1-3 and/or omega-5-gliadin. Eight infants (0.7%) were sensitized to inhalant allergens. Maternal sensitization to food allergens was associated with infant sensitization, odds ratio 3.64 (95% CI 1.53-8.68). CONCLUSION: Already at 3 months of age, 7% were sensitized to food, mostly without detectable s-IgE to food allergen molecules, and <1% to inhalant allergens. Maternal food sensitization was associated with infants' sensitization.

Fetal thoracic circumference in mid-pregnancy and infant lung function.

BACKGROUND AND AIM: Impaired lung function in early infancy is associated with later wheeze and asthma, while fetal thoracic circumference (TC) predicts severity of neonatal lung hypoplasia. Exploring fetal origins of lung function in infancy, we aimed to determine if fetal TC in mid-pregnancy was associated with infant lung function. METHODS: From the prospective Scandinavian general population-based PreventADALL mother-child birth cohort, all 851 3-month-old infants with tidal flow-volume measurements in the awake state and ultrasound fetal size measures at 18 (min-max 16-22) weeks gestational age were included. Associations between fetal TC and time to peak tidal expiratory flow to expiratory time (tPTEF /tE ) were analyzed in linear regression models. To account for gestational age variation, we adjusted TC for simultaneously measured general fetal size, by head circumference (TC/HC), abdominal circumference (TC/AC), and femur length (TC/FL). Multivariable models were adjusted for maternal age, maternal asthma, pre-pregnancy body mass index, parity, nicotine exposure in utero, and infant sex. RESULTS: The infants (47.8% girls) were born at mean (SD) gestational age of 40.2 (1.30) weeks. The mean (SD) tPTEF /tE  was 0.39 (0.08). The mean (SD) TC/HC was 0.75 (0.04), TC/AC 0.87 (0.04), and TC/FL 4.17 (0.26), respectively. Neither TC/HC nor TC/AC were associated with infant tPTEF /tE while a week inverse association was observed between TC/FL and tPTEF /tE  ( ß ^ $\hat{\beta }$ = -0.03, 95% confidence interval [-0.05, -0.007], p = 0.01). CONCLUSION: Mid-pregnancy fetal TC adjusted for fetal head or abdominal size was not associated with tPTEF /tE in healthy, awake 3-month-old infants, while a weak association was observed adjusting for fetal femur length.

Stopping when knowing: use of snus and nicotine during pregnancy in Scandinavia.

In young women, the use of snus increases in parallel with decreasing smoking rates but the  use in pregnancy is unclear. Our aims were to determine the prevalence of snus use, smoking and other nicotine-containing product use during pregnancy, and to identify predictors for snus use in pregnancy. Prevalence was determined for 2528 women in Norway and Sweden based on the Preventing Atopic Dermatitis and ALLergies (PreventADALL) study, a population-based, mother-child birth cohort. Electronic questionnaires were completed in pregnancy week 18 and/or week 34, and potential predictors of snus use were analysed using logistic regression models. Ever use of any snus, tobacco or nicotine-containing products was reported by 35.7% of women, with similar rates of snus use (22.5%) and smoking (22.6%). Overall, 11.3% of women reported any use of nicotine-containing products in pregnancy up to 34 weeks, most often snus alone (6.5%). Most women (87.2%) stopped using snus by week 6 of pregnancy. Snus use in pregnancy was inversely associated with age and positively associated with urban living and personal or maternal history of smoking. While 11.3% of women used snus or other nicotine-containing products at some time, most stopped when recognising their pregnancy. Younger, urban living, previously smoking women were more likely to use snus in pregnancy.