Background: Risks for coronary heart disease (CHD) and diabetes (T2DM) of the 'hypertriglyceridemic waist' phenotype (HtgW) warrant further investigation. We studied this issue and whether partial proinflammatory conversion of apolipoprotein (apo) A-I by lipoprotein(a) [Lp(a)] is a codeterminant. Materials and Methods: In a population-based prospective study, 1328 Turkish adults were analysed in four groups by the presence of abdominal obesity and elevated triglycerides (Htg). Results: LDL-cholesterol levels, significantly elevated in isolated Htg, were lower in HtgW, yet significantly higher apoB and complement C3 values existed in women with HtgW in whom also the lowest Lp(a) values prevailed. Lp(a) was linearly associated, more strongly in HtgW than in the remaining groups, with apoB and, in women inversely, with gamma-glutamyltransferase. Incident HtgW was predicted, not in men, but in women inversely by Lp(a) (OR 0·80 [95%CI 0·65; 0·97]), regardless of adjustment for relevant confounders. After adjustment for conventional risk factors, HtgW (OR 2·84) and high apoA-I/HDL-C ratio (OR 1·50) were significantly and additively associated with combined prevalent and incident CHD risk. High apoA-I and low HDL-cholesterol levels interacted therein in women. Type-2 diabetes was strongly predicted by HtgW, mediated in men by high apoA-I/HDL-C ratio. Conclusion: HtgW is associated with excess inflammatory markers, is predicted in women paradoxically by lower circulating Lp(a) and is associated in both sexes with marked excess cardiometabolic risk to which high apoA-I/HDL-C ratio contributes additively. These findings are consistent in women with apoA-I being oxidized via aggregation to Lp(a). © 2013 Stichting European Society for Clinical Investigation Journal Foundation. Published by John Wiley & Sons Ltd.