Biomarkers of dairy fat intake and risk of cardiovascular disease: A systematic review and meta analysis of prospective studies

Background: Circulating biomarkers of dairy fat provide objective measures of dairy fat intake and facilitate conclusions relevant to populations with different diets and susceptibility to cardiovascular diseases (CVD). Objective: To assess the relationship between circulating pentadecanoic acid (15:0), heptadecanoic acid (17:0) and trans-palmitoleic acid (trans-16:1n-7) and the risk of CVD. Methods: Pubmed, Medline and Embase were searched for prospective cohort studies of the relationship between biomarkers of dairy fat and CVD risk, which included coronary heart disease (CHD), stroke, heart failure and CVD mortality, supplemented by bibliographies of retrieved articles and previous reviews. For each study, relative risks (RR) and 95% confidence intervals (CI) were extracted and pooled with the random effect model. Results: Thirteen studies involving 7,680 CVD cases were included. The pooled RRs of the risk of CVD for the top third vs. bottom third 15:0, 17:0 and trans-16:1n-7 level were 0.94 (95%CI: 0.77-1.15), 0.82 (95% CI: 0.68-0.99) and 0.82 (95% CI: 0.67-1.02), respectively. Subgroup analysis indicated that there were no associations between the concentration of 15:0 with CHD and stroke, but a negative relationship with heart failure (RR = 0.72, 95% CI: 0.55-0.95). Null association was observed between circulating 17:0 and trans-16:1n-7 level and subtypes of CVD except for only one study which reported a negative relationship between 17:0 and heart failure. Conclusion: Higher dairy fat exposure is not associated with an increased risk of CVD.