ISEE/ISEA 2006 Conference Abstracts Supplement: Poster Abstracts: Abstracts
In the 1980-ies a very strong association was found between the incidence of adverse pregnancy outcomes (spontaneous abortion and stillbirth) and the arsenic level of drinking water in some settlements of County Bekes supplied with piped water containing high level of arsenic (above 100 microgram/litre) and low level of iodine. After enormous effort has been made to decrease (by the end of 1990-ies) the arsenic level in the drinking water below 50 microgram/L in each settlement of Hungary, there was no data available whether this change was enough to eliminate the adverse pregnancy outcomes seen earlier. Therefore we conducted a retrospective ecological study on the association between the incidence of adverse pregnancy outcomes and the arsenic level of the drinking water in all the 71 settlements of County Bekes.
All the data on the pregnancy outcomes between 1998 and 2002 were collected for all the 71 settlements of County Bekes, using the annual reports of the district nurses providing pregnancy care for the newly registered pregnant women. Data on the arsenic level of the drinking water supplying the settlements were based on the measurements performed in 1999 as part of the National Environmental Health Action Programme. (No changes were recorded in the arsenic levels in these settlements between 1998 and 2002. The new legislation with the 10 microgram/L health limit value appeared in 2001.) Poisson regression was used for analysis, using STATA 7.0 programme.
In the 71 settlements during the 5 year period altogether 17,813 live births, 1,062 spontaneous abortions and 135 stillbirths were recorded. In 35 settlements the arsenic level of the drinking water was below 10 microgram/L. Taking this as a reference value, the incidence rate ratios (and their 95% confidence intervals) for spontaneous abortions (corrected for the number of inhabitants) were 0.99 (0.87–1.12), 1.16 (1.001–1.34), 1.20 (1.03–1.42) and 1.23 (1.01–1.52) in settlements supplied with drinking water with arsenic level above 15, 20, 25 or 30 microgram/L, respectively. Similar association between the arsenic concentration and the incidence of stillbirths could not be observed.
As already reported for the settlements supplied with drinking water > 50 microgram/L arsenic, a significantly increased risk of spontaneous abortion could also be seen in settlements supplied with drinking water arsenic level above 20 microgram/L.