Mercury, lead and cadmium in human milk in relation to diet, lifestyle habits and sociodemographic variables in Madrid (Spain).

BACKGROUND: Although breastfeeding is the ideal way of nurturing infants, it can be a source of exposure to toxicants. This study reports the concentration of Hg, Pb and Cd in breast milk from a sample of women drawn from the general population of the Madrid Region, and explores the association between metal levels and socio-demographic factors, lifestyle habits, diet and environmental exposures, including tobacco smoke, exposure at home and occupational exposures. METHODS: Breast milk was obtained from 100 women (20 mL) at around the third week postpartum. Pb, Cd and Hg levels were determined using Atomic Absorption Spectrometry. Metal levels were log-transformed due to non-normal distribution. Their association with the variables collected by questionnaire was assessed using linear regression models. Separate models were fitted for Hg, Pb and Cd, using univariate linear regression in a first step. Secondly, multivariate linear regression models were adjusted introducing potential confounders specific for each metal. Finally, a test for trend was performed in order to evaluate possible dose-response relationships between metal levels and changes in variables categories. RESULTS: Geometric mean Hg, Pb and Cd content in milk were 0.53 µg L(-1), 15.56 µg L(-1), and 1.31 µg L(-1), respectively. Decreases in Hg levels in older women and in those with a previous history of pregnancies and lactations suggested clearance of this metal over lifetime, though differences were not statistically significant, probably due to limited sample size. Lead concentrations increased with greater exposure to motor vehicle traffic and higher potato consumption. Increased Cd levels were associated with type of lactation and tended to increase with tobacco smoking. CONCLUSIONS: Surveillance for the presence of heavy metals in human milk is needed. Smoking and dietary habits are the main factors linked to heavy metal levels in breast milk. Our results reinforce the need to strengthen national food safety programs and to further promote avoidance of unhealthy behaviors such as smoking during pregnancy.

[EpiData: the natural heir to EpiInfo 6?]. / EpiData: el heredero natural de EpiInfo 6?

EpiData is an epidemiological software developed by the EpiData Association (www.epidata.dk). Following the EpiInfo 6 philosophy, Epidata, offers all the advantages of EpiInfo 6: simplicity, applicability, few operation and communication system requirements, widening them with a clear focus on data quality and documentation plus the advantages that, for many users, has the Windows operating system. The aim of this Note is to introduce to potential users the strengths and limitations of EpiData, a software that can become in a short time the equivalent to what EpiInfo 6 was a few years ago.