Novel inflammatory markers PAF and Lp-PLA2 in cardiovascular disease prevention: relationships with dietary patterns and traditional risk factors

Student thesis: Doctoral Thesis

Abstract

Valid methods of measuring inflammatory pathways within the arteries are needed for the detection and monitoring of the progression of inflammation involved in atherosclerosis. Two novel biomarkers that have been identified as potential risk markers of cardiovascular disease (CVD) include platelet-activating factor (PAF) and lipoprotein-associated phospholipase A2 (Lp-PLA2). Research on PAF is very limited especially in clinical settings. Research on Lp-PLA2 exists on a larger scale however much of the research has examined plasma mass and not enzyme activity which is a better predictor of the atherogenic nature of Lp-PLA2. There is very limited research on the relationship these markers have with food groups and dietary patterns with some early evidence showing an association with Mediterranean diets. In addition, recent research has highlighted an association between plant-based diets and other markers of inflammation. More research is needed on these markers to understand the independent role they play in CVD and how they relate to diet to better assess their utility in clinical settings.

This thesis firstly reports on the relationship with these novel markers of inflammation as well as C-reactive protein (CRP) and traditional risk factors of CVD such as blood cholesterol, triglycerides, blood pressure, physical activity, body mass index (BMI) and waist circumference to better understand the role these markers play in CVD progression. Secondly, this thesis reports on specific food groups and healthy dietary patterns that are associated with lower levels of these markers.

A cross sectional study was conducted. One hundred adults (49 ± 13 years, 31% male) with variable CVD risk were recruited. Fasting inflammatory markers PAF, Lp-PLA2 and hsCRP and total, high-density lipoprotein (HDL), low-density lipoprotein (LDL) cholesterol, and triglycerides were measured. Blood pressure, body mass index, and waist circumference were measured. Dietary intake was assessed via validated FFQ’s. Individual foods consumed were converted into serves and classified into food groups. Validated diet scores were calculated for adherence to DASH diet, Vegetarian Lifestyle Index, Healthy Eating Index for Australian Adults and Mediterranean diet. Medical and physical activity data were self-reported. PAF and Lp-PLA2 were associated with several traditional CVD risk factors however in different ways. The consumption of cruciferous vegetables and cheese was associated with PAF but the association with cheese did not reach significance in the adjusted models. There was no association of any dietary pattern and PAF. No healthy food group or dietary pattern was associated with Lp-PLA2 in adjusted models. There was an association with cheese and Lp- PLA2 in the unadjusted model, but this did not reach significance. The lack of association with these novel markers of inflammation and other healthy food groups and dietary patterns could be due to the small sample size or to COVID-19 infection and/or vaccination given the timing of data collection. Significant associations with other healthy food groups and dietary patterns may be uncovered by examining a larger sample size and reassessing during non-pandemic settings. In contrast there were several significant findings for CRP, a more traditional marker of inflammation, and food groups and dietary patterns. There was a large negative correlation with nuts and legumes consumption and CRP. In addition, higher adherence to all healthy dietary patterns assessed was associated with lower CRP, with the strongest relationship seen with Vegetarian Lifestyle Index, DASH Index and Dairy-adjusted DASH Index.
Date of Award2024
Original languageEnglish
SupervisorDianne Reidlinger (Supervisor), Hannah Mayr (Supervisor) & Anna Lohning (Supervisor)

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