Blood levels of lead and dental caries in permanent teeth

Abstract

Objectives: The purpose of this study was to determine whether there is an association between lead exposure within the ages of 1-4 years and dental caries in the permanent dentition between ages 9-17 among Mexican youth. Methods: Data were collected for the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) cohort from a group of 490 children born and reared in Mexico City. Among ages 1-4 years, blood lead levels were measured in micrograms of lead per deciliter of blood (μg/dL) and the presence of caries in adolescence was determined using the International Caries and Detection and Assessment System (ICDAS). The relationship between blood levels of lead and decayed, missing, or filled surfaces (DMFS) was examined using negative binomial regression. Covariates were selected based on previous studies and included age, gender, socioeconomic status, oral hygiene, body mass index, and diet. The nonlinear relationship between lead and DMFS was examined using smoothing splines. Results: The mean overall blood lead level (BLL) was 4.83 μg/dL (S.D. of 2.2). The mean overall caries level (DMFS) was 4.1. No statistically significant association was found between early childhood blood lead levels and dental caries in adolescence. Conclusion: This study shows a lack of association between exposure to lead between the ages of 1-4 years of age and dental caries in permanent dentition later in life. Other covariates, such as age and sugar consumption, appeared to play a more prominent role in caries development.

The Association between Lead Exposure and Dental Caries: A Systematic Review

“…Eleven studies [16‒19, 21, 24‒29] measured the blood lead (PbB) level through either whole blood or plasma. Two studies [26, 30] measured salivary lead (PbSa) level using unstimulated whole saliva samples.…”

“…Sixteen studies were identified for this review, comprising a total of 35,743 participants. Four studies were cohort studies [16][17][18][19], while the remainder were crosssectional [20][21][22][23][24][25][26][27][28][29][30]. The studies were conducted in various countries, including the USA [16,17,21,[25][26][27][28] (n = 7), Brazil [23] (n = 1), Canada [31] (n = 1), Mexico [18,19] (n = 2), Serbia [20] (n = 1), South Korea [24] (n = 1), Spain [22] (n = 1), Thailand [29,30] (n = 2).…”

“…Potential confounding factors included age, sex, race/ethnicity, parental education level, socio-economic level, exposure to smoking, fluoride exposure, and toothbrushing frequency. One study [19] was assigned as high risk of bias due to lack of reporting on additional analysis performed. Four studies [20,22,26,30] were assigned as very high risk of bias due to either a lack of adjustment for confounding variables or lack of information on whether such adjustments were made.…”

“…Four studies were cohort studies [16][17][18][19], while the remainder were crosssectional [20][21][22][23][24][25][26][27][28][29][30]. The studies were conducted in various countries, including the USA [16,17,21,[25][26][27][28] (n = 7), Brazil [23] (n = 1), Canada [31] (n = 1), Mexico [18,19] (n = 2), Serbia [20] (n = 1), South Korea [24] (n = 1), Spain [22] (n = 1), Thailand [29,30] (n = 2). Six studies [17,21,24,25,29,30] examined both deciduous and permanent dentition.…”

“…Kim et al [24] reported a mean PbB of less than 2 μg/dL. Two studies [18,19] reflect Mexico's ongoing problem with Pb toxicity [35]. Youravong et al [36] specifically conducted studies from an area of high Pb exposure in Thailand.…”