Maternal BMI, early-life growth, and atopic dermatitis by age 3 years.

Background: Childhood atopic dermatitis is associated with maternal gestational weight gain, whereas an association with prepregnancy body mass index (ppBMI) or fetal and newborn anthropometric measurements is unclear. Objective: Our aim was to determine whether, primarily, maternal ppBMI and, secondarily, offspring newborn anthropometric measurements or fetal growth are associated with atopic dermatitis by age 3 years. Methods: In 2107 mother-child pairs (54% boys) from the general population-based Scandinavian PreventADALL (Preventing Atopic Dermatitis and Allergies) cohort, maternal ppBMI was reported at time of enrollment (at midpregnancy). Thoracic and abdominal circumferences were measured by ultrasound at midpregnancy and again at birth, as were weight and length. Fetal growth, including thoracic and abdominal growth and fetal weight gain, was estimated from midpregnancy to birth. Atopic dermatitis was diagnosed using standard criteria at 3, 6, 12, 24, and age 36 months. Results: Atopic dermatitis was diagnosed in 525 of the 2107 children (25%) by age 3 years, with a positive association with increasing maternal BMI (adjusted odds ratio [aOR] per BMI unit = 1.03 [95% CI = 1.00-1.06]). Furthermore, increasing birth length (mean = 50.5 ± 2.0 cm) was positively associated with atopic dermatitis (aOR = 1.06 [95% CI = 1.01-1.12]), whereas short birth length (<48 cm) was inversely associated with atopic dermatitis (aOR = 0.71 [95% CI = 0.51-1.0]). Neither birth weight nor thoracic, abdominal, or upper arm circumference at birth nor fetal growth was associated with atopic dermatitis. Conclusion: Increasing maternal ppBMI and increasing birth length were positively associated with offspring atopic dermatitis by age 3 years, whereas short birth length was associated with a lower risk of atopic dermatitis.