Growth secular trend during early childhood in Northern Spain

Abstract

To check whether secular changes exist in growth pattern of caucasic children from the North of Spain up to 2 years of age compared with 25-30 years ago population growth curves. Longitudinal study of a representative cohort of caucasic infants born a term in Aragon (n=1.099). Standard deviation scores (z-scores) for weight, length and body mass index (BMI) have been calculated by two available 25-30 years ago population growth curves (Sobradillo et al. and Ferrández et al.). At all ages, weight, length and BMI mean z-scores significantly vary depending on the growth standard curve used (p≤0.001). At birth, weight z-score is -0.36 (95%CI:-0.42;-0.30) according to Sobradillo et al. and -0.26 (95%CI:-0.29;0.33) according to Ferrández et al. These differences decreased progressively becoming minimum at 2 years (mean weight z-score -0.08 and -0.05; respectively). At this age, length mean z-score is +0.54 (95%CI:0.48;0.61) according to Sobradillo et al. and +0.19 (95%CI:0.12;0.25) according to Ferrández et al. Mean BMI z-scores of our sample showed lower values than selected standards. Current birth weight of caucasic infants from Northern Spain is lower than in the previous generation. At 2 years of age there is a trend of increasing length, with a similar weight, resulting in lower BMI values.