Cord-blood levels of heavy metals, vitamin D and calcium and the occurrence of development defects of enamel in primary incisors: A birth cohort study

Abstract

This study investigated the influence of vitamin D, calcium and heavy metals on the frequency of development defects of enamel (DDE) in primary incisors of infants. Serum levels of vitamin D, calcium, arsenic, cadmium, lead, and mercury in cord blood, as well as prenatal and perinatal data, were collected during pregnancy, at birth, and in follow-ups with newborns and infants ≤ 24 months. This was done using laboratory exams, interviews, and newborns’ and infants’ records. An examiner performed dental exams using the Modified DDE. DDE type, color, location, and severity were evaluated, and logistic multiple regression models were analyzed (p < 0.05). Of the infants (n = 306), 52.3 % were boys; 14.4 % were premature; 93.0 % were born to mothers taking medication, 89.9 % to mothers taking vitamin supplements, 38.1 % to mothers who used alcohol, and 11.4 % to mothers who used tobacco. Most newborns had normal weight (88.9 %), adequate size for gestational age (88.1 %), 1-minute APGAR score ≥ 7 (88.6 %), and were exclusively breastfed at discharge from maternity (90.6 %). Arsenic ≥ 0.23 µg/L (53.4 %), cadmium < 0.20 µg/L (52.6 %), lead ≥ 0.8 µg/dL (60.5 %) and mercury ≥ 0.8 µg/L (55.2 %) were found in this population. Most had normal vitamin D (52.6 %) and calcium (76.3 %) levels. The incidence of DDE in infants was 27.1 % (83/306). The number of DDE per child ranged from 1 to 8 with demarcated opacity being the most common defect, while upper central incisors and the incisal third were the teeth and location most affected, respectively. Lead was associated with DDE in primary incisors, except in cases of pregnant women taking vitamin supplements and when the newborn, at the time of discharge, was being breastfed. In the present population, high cord blood levels of lead were associated with the occurrence of DDE in primary incisors.