Spatially disaggregated population estimates in the absence of national population and housing census data.

Population numbers at local levels are fundamental data for many applications, including the delivery and planning of services, election preparation, and response to disasters. In resource-poor settings, recent and reliable demographic data at subnational scales can often be lacking. National population and housing census data can be outdated, inaccurate, or missing key groups or areas, while registry data are generally lacking or incomplete. Moreover, at local scales accurate boundary data are often limited, and high rates of migration and urban growth make existing data quickly outdated. Here we review past and ongoing work aimed at producing spatially disaggregated local-scale population estimates, and discuss how new technologies are now enabling robust and cost-effective solutions. Recent advances in the availability of detailed satellite imagery, geopositioning tools for field surveys, statistical methods, and computational power are enabling the development and application of approaches that can estimate population distributions at fine spatial scales across entire countries in the absence of census data. We outline the potential of such approaches as well as their limitations, emphasizing the political and operational hurdles for acceptance and sustainable implementation of new approaches, and the continued importance of traditional sources of national statistical data.

The IUD and anemia: a study of hematocrit.

PIP: Lippes Loop D or Copper T-200 devices were randomly assigned to 400 women in Santiago, Chile, none of whom had been recently pregnant, in the effort to test the relationship between IUD use and anemia and the effect of daily iron supplements on hematocrit levels in conjunction with IUD use. The mean age for the acceptor group was 25.4; the mean parity was 1.9. Daily iron supplements were randomly assigned to 200 women in the group. Daily iron supplements were given to 21 women in the non-iron group who were admitted with hematocrit values of less than 30%. Hematocrit readings were performed at admission and at each subsequent follow-up. Readings were performed on cervical samples at 1, 3, 6 and 12 month follow-up visits. Mean admission hematocrit values were compared to the corresponding values at each follow-up via a paired t-test. There were no significant differences found for users of either IUD in the group taking daily iron supplements. In the non-supplement group, there were significant declines in hematocrit levels at 3 and 6 months after IUD insertion. At 12-months post-insertion, the mean hematocrit values for all groups increased from the 6-month level. Women taking iron supplements had lower rates of expulsion and removal for bleeding and pain, but the results were insignificant.^ieng