Space-time latent component modeling of TSH in newborns

Abstract

Iodine deficiency is a serious threat to public health throughout the world. The lack of iodine could result in major detrimental diseases and underdevelopments, especially for newborn babies. In Spain, screening of iodine deficiency was done by means of a heel prick in newborns, which allows measuring the concentration of thyroid-stimulating hormones (TSH), a hormone which triggers the thyroid gland. This study concentrates on the area of Galicia, situated in the northwestern part of Spain. The gathered information on the TSH levels served as a guide to highlight areas that could be considered as iodine deficient, in the sense that in iodine deficient areas the mean TSH levels in newborns is higher. In this paper, a space-time latent component model was constructed in order to study how TSH levels changed in time. Results indicated that there were two distinct components which followed a different temporal trend between 2004 and 2009. Furthermore the characteristics Gender and Feeding Type were investigated as well and found to have an impact on the TSH levels overall.