Dietary Quality Transition Over Time and its Association with Cardiometabolic Risks Among Adults in China

The expanding burden of obesity and associated cardiometabolic risk (CM) in Asian populations is of particular concern given their higher CM risk at lower BMI level and at younger ages relative to Western populations. An index-based diet quality approach is a useful way to capture the complex interplay of dietary constituents and fully investigate the overall diet - disease relationship. Many studies have shown that Alternative Healthy Eating Index-2010(AHEI-2010), created based on Harvard Healthy Eating Pyramid (HEP), were negatively associated with the risks of obesity, dyslipidemia, diabetes, some cancer and mortality in US and European population. Using the panel data of China Health and Nutrition Survey from 1991 to 2011, we examined the association of index-based current diet quality (one time point of 2006 wave) or long-term diet quality trends (from 1991 to 2006) and cardiometabolic risks among adults aged 18 to 65 in China. In Aim 1, we used Chinese dietary guidelines to create the China dietary quality index (CDQI) and tailored the AHEI-2010 to match the Chinese diet (named as tAHEI). Then we examined the association between the CDQI and tAHEI score in 2006 with risk of diabetes and major CM risks in 2009. We found that the CDQI and tAHEI score showed similarly negative associations with risk of low density lipoprotein cholesterol (LDL-C), whereas the CDQI score was positively associated with elevated triacylglycerol risk in women. Aim 2 investigated socioeconomic disparity in 20-year diet quality transition. Results indicated that the past two decades brought moderate improvement in overall diet quality across the entire distribution, with greater improvement in those starting with better diet quality. In Aim 3 we evaluated the association of 15-year diet quality trends with diabetes biomarkers in 2009. High baseline score and high increase in the score were independently associated with lower Homeostasis Model of Insulin Resistance (HOMA-IR) and insulin but not related to fasting glucose, hemoglobin A1c and defined diabetes with certain exception. In conclusion, our findings suggest that diet consistent with Harvard HEP had beneficial impact on improving insulin resistance and LDL-C. Future nutrition intervention and policy should give priority to adults with poor diet quality who generally have lower incomes and live in lower urbanized communities or southern China.Doctor of Philosoph