8 ��g/dL eleven years later, i.e., a lowering of about 55% [12]. In Helsinki, the mean concentration of lead in the blood of children in day-care centers was 4.6 ��g/dL in 1983 and 3.0 ��g/dL five years later [13]. However, in much of the world such as African nations, progress to reduce exposure to this toxic element has been slower. In 2002, Sudan was the only one of the 48 Sub-Saharan selleck Dorsomorphin countries to entirely use unleaded gasoline. In May 2004, more than half of the gasoline sold in Sub-Saharan Africa was unleaded. On December the 27th, 2005, the United Nations Environment Program (UNEP) declared that the promise made to free Sub-Saharan Africa from leaded gasoline had just been fulfilled, and that the campaign in favor of suppression of lead in fuel was on the way to become a real success story in the developing world.

In 2009, ongoing efforts by African countries at the UNEP to eliminate lead from gasoline are to be lauded, because they have greatly improved the cognitive potential of future generations of children [14]. In the DRC (Democratic Republic of Congo), although there are multiple sources of lead exposure, leaded gasoline is a common high dose source of exposure for children living in Kinshasa: surveys conducted in 2004 and 2008 shown that the prevalence of elevated BLLs was 63% and 71% respectively [15,16] that indicates a public health issue which requires corrective actions. A process of phasing out leaded gasoline started in December 2005 (Declarations of Dakar in 2001 and Johannesburg in 2002) and completed in December 2009 in DRC.

A short visit in December 2010 to the various gas stations of Kinshasa city indicated that there are no gas pumps with leaded gasoline (data not shown). The present study originated from that observation and its main objective was to test for reduction in pediatric BLLs in Kinshasa, DRC, by comparing BLLs collected in 2011 (2 years after use of leaded gasoline was phased out in Kinshasa) to those collected in surveys conducted in 2004 and 2008 (when leaded gasoline was still used in Kinshasa). Methods In the absence of reliable population registers and in view of the practical difficulties of conducting a truly random sampling in the population of Kinshasa, we applied a two-stage systematic sampling approach [17].

In the first Entinostat stage, the 22 administrative entities of Kinshasa were listed in alphabetical order and 11 out of them were selected as follows: a first entity was drawn randomly from the list and every other subsequent entity was then included, thus ensuring a comprehensive coverage of the entire urban area of Kinshasa. In the second stage, we aimed to recruit about 10 healthy boy and girl subjects between 1 and 5 years old from each of the 11 entities. 110 parents of children were contacted by project staff to take part in this survey.