Methodology and challenges for harmonization of nutritional data from seven historical studies.

Background: Collection of detailed dietary data is labor intensive and expensive, harmonization of existing data sets has been proposed as an effective tool for research questions in which individual studies are underpowered.

Methods: In this paper, we describe the methodology used to retrospectively harmonize nutritional data from multiple sources, based on the individual participant data of all available studies, which collected nutritional data in Israel between 1963 and 2014. This collaboration was established in order to study the association of red and processed meat with colorectal cancer.

Inequalities in end-stage renal disease: underprivileged and ethnic minority members are at higher risk.

Background: Incidence of end-stage renal disease (ESRD) is higher in Israel than the European average. Socio-economic differences in ESRD have been reported globally, but many countries lack a national register. Using national data, we assessed which socio-demographic factors are associated with 5-year incidence of ESRD in Israel, where there is universal access to renal replacement therapy (RRT).