NIDDK Genetics of Metabolic Syndrome in an Island Population

The major objective of this study was to conduct a systematic genetic study of metabolic traits involved in metabolic syndrome through collection and analysis of epidemiological, demographic, environmental, and relevant biological and clinical data from a relatively isolated island population of the eastern Adriatic coast of Croatia. The population was chosen for the following reasons: 1) in spite of practicing a largely traditional life style and dietary habits, high rates of obesity, arterial hypertension, dyslipidemia and related metabolic abnormalities were found in previous studies; 2) the population was established by a relatively small number of founders, predominantly of Slavic descent from the mainland during 15th to 18th century AD, a genetically homogeneous population living in a homogeneous environment; 3) sharing a common European ancestry, a relevant population for study in the context of the general US population; 4) Croatian collaborators have been conducting anthropological and genetic studies in these communities for over three decades. There were two major aims of the study: 1) to recruit ~1200 adult participants and collect blood samples together with demographic, anthropometric, environmental and clinical data from the island of Hvar; to perform biochemical tests to measure glucose, insulin, uric acid and lipid levels; 2) conduct a genome-wide association analysis of metabolic traits and phenotypes using genome-wide SNP arrays (Affymetrix Genome-Wide Human SNP Array 5.0). ]]>
Subjects, pedigree-related and unrelated, were included based on voluntary participation from five villages in the middle Dalmatian Croatian island of Hvar. The study sample was obtained through non-probability sampling methods; village leaders advertised the study and volunteers meeting age requirements were included. There was no consideration for disease status or use of medication. Informed written consent was obtained from all participants. Anthropometric measurements, blood pressure were obtained from subjects above the age of 18 years. Blood samples for measuring biochemical traits and isolation of DNA were obtained only from subjects above 20 years of age. ]]>
The present day Croatian islanders emigrated from the mainland during 6th to 18th century AD and have remained relatively isolated since that time. In spite of practicing a largely traditional life style and adherence to a Mediterranean diet, rates of obesity and hypertension was found to be high. Preliminary studies conducted by the PI and collaborators also documented a high prevalence of metabolic syndrome. A unique population history leading to reduced genetic diversity, homogeneous life-style, environmental exposures, high prevalence of obesity-related traits were considered advantageous and ideal to design and launch a systematic study to identify genetic factors associated with metabolic syndrome and relevant traits. ]]>