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Samoan islanders Cardiovascular disease risks.
– Reported, January19 2013
The rapid temporal rise of Samoan obesity and obesity-related diseases has been attributed to modernization and its associated nutritional transition, in which these developing nations are consuming more calorie-rich foods and expending less energy.1 Although these behavioral factors are linked to obesity and obesity-related diseases, genetic factors have also been shown to play an important role in Samoan obesity and obesity-related risk factors.
Cardiovascular disease is characterized by atherosclerotic plaques, resulting in various cardiovascular morbidities and mortalities. Elevated levels of peripheral LDL, as well as decreased levels of peripheral HDL are known risk factors for atherosclerosis. DNA methylation in a substantial fraction of the genome has been related to atherosclerosis and has been found to precede the formation of atherosclerosis .
A prominent feature of atherogenesis is an inflammatory response, in which inflammatory cells, including lymphocytes, become upregulated. Previous work has shown that different cell types have unique patterns of DNA methylation. Specifically, different inflammatory cells from peripheral blood samples have been shown to have varied levels of LINE-1 methylation; specifically, lymphocytes were associated with lowered levels of LINE-1 methylation.
Finally, we found a significant positive association between LINE-1 methylation and BMI that was particularly prominent among women. Although the mechanism responsible for this relationship is unclear, it is of interest due to the fact that increased BMI is a risk factor for cardiovascular disease. Prior work in substantially less obese populations has not observed a significant association of BMI with LINE-1 methylation, although the direction of the (non-significant) associations was the same as we observed in Samoa and American Samoa.
It would be interesting to conduct longitudinal analyses in order to more clearly understand the relationships between homocysteine, inflammation and DNA methylation in the development of cardiovascular disease; this is critically important due to the fact that cardiovascular disease is currently the top cause of death globally.
CREDITS:Haley L Cash, Stephen T McGarvey, E. Andres Houseman, Carmen J Marsit, Nicola L Hawley, Geralyn M Lambert-Messerlian, Satupaitea Viali, John Tuitele and Karl T Kelsey
