Fatty Acids, Cardiovascular Diseases, and Diabetes Mellitus

Cardiovascular disease (CVD) is the number one cause for mortality and morbidity around the world. Meanwhile, diabetes mellitus (DM) has become an emerging epidemic, causing 1.5 million deaths in 2012, with 80% occurring in low- and middle-income countries. Substantial evidence has linked both lifestyle and metabolic risk factors to increased risk of CVD and death, with suboptimal diet being the single leading modifiable cause of poor health (Lim. SS, et al, Lancet 2012). Of 20 top individual causes of disease burden worldwide, 8 are related to poor nutrition, including suboptimal intakes of various dietary fatty acids. Although previous studies have found divergent health effects of different dietary fatty acids on health, gaps still exist in terms of the scientific knowledge (e.g. how individual circulating vs. dietary trans fatty acid subtypes affect health) and related disease burdens (e.g. national CHD mortality burdens attributable to suboptimal intakes of fatty acids). These gaps have motivated my dissertation researches. In chapter one and two, I investigated the prospective associations of five subtypes of plasma phospholipid trans fatty acid (TFA) levels with the risk of various disease endpoints, including total, CVD and non-CVD mortality, incident coronary heart disease (CHD) and DM. In chapter two, I also examined the prospective associations of total and subclasses dietary TFA with risk of DM. The analyses were conducted using the Cardiovascular Health Study, a community-based multicenter prospective cohort consisted of older Americans. The risks were estimated using the Cox proportional hazard model. The study in chapter three was a collaborative effort of the Nutrition and Chronic Diseases Expert Group as part of the 2010 Global Burden of Diseases, Injuries, and Risk Factors study. Using the comparative risk assessment framework, I comprehensively quantified the CHD mortality attributable to suboptimal intakes of saturated fat, omega-6 polyunsaturated fat, and TFA in 186 countries in 1990 and 2010, by age and sex groups. I also estimated the regional and country level trends of these attributable CHD burdens from 1990 to 2010. The findings of this study are relevant for informing regional and country level public health policy priorities.