The differential impact of abdominal obesity on fasting and non-fasting triglycerides and cardiovascular risk

We previously showed that abdominal obesity is associated with increased TG levels after a high-fat meal, irrespective of fasting levels. However, whether these findings are applicable to the general population and have implications for cardiovascular disease (CVD) risk remains uncertain. We aimed to examine the effects of abdominal obesity on fasting and non-fasting TG and CVD risk in the UK Biobank.

Random TG levels were measured in 352,782 individuals and fasting duration was self-reported. We used waist-hip ratio adjusted for BMI (WHRadjBMI) and its polygenic score to assess abdominal obesity and tested for interactions with fasting duration on TG levels. We evaluated the implications for CVD risk by analysing associations with the incidence of myocardial infarction and stroke.

Fasting duration modified the effect of the WHRadjBMI phenotype and its polygenic score on TG levels (PInteraction= 6.5x10-32 and PInteraction=0.034). The polygenic score increased non-fasting TG 0.1 mmol/L more than fasting TG per standard deviation increase in WHRadjBMI. Higher TG levels, regardless of fasting status, were associated with higher CVD risk. The association between WHRadjBMI polygenic score and CVD risk was attenuated by 27% (from HR=1.41 to HR=1.30) after adjusting for non-fasting TG levels, and by 11% (from HR=1.38 to HR=1.34) after adjusting for fasting TG levels.

Polygenic score for abdominal obesity has a stronger effect on non-fasting than fasting TG levels, reflecting impaired postprandial lipid metabolism. Measuring TG levels in fasting state may underestimate CVD risk in individuals with abdominal obesity.