Postprandial Cardiometabolic Parameters in Older Adults with Normal-Weight Obesity: A Cross-Sectional Pilot Study.

BACKGROUND/OBJECTIVES: Normal-weight obesity describes those with a normal body mass index (BMI) and high body fat percent. Older adults with normal-weight obesity (NWO-O) are at increased risk for cardiovascular disease (CVD), but underlying mechanisms remain unclear. This pilot study examined whether NWO-O had an unfavorable cardiometabolic response to acute high-fat meal intake compared to normal BMI, low body fat percent individuals that were both older (NWL-O) and younger (NWL-Y). METHODS: Participants (N = 29) with a normal BMI were grouped as follows: NWL-Y (18-35 years, low body fat percent; n = 12), NWL-O (≥60 years, low body fat percent; n = 9), and NWO-O (≥60 years, high body fat percent; n = 8). All participants completed an abbreviated fat tolerance test (75 g fat). Fasting and 4 h blood samples were collected to measure lipids (triglycerides and high-density lipoprotein cholesterol [HDL-C]), biomarkers of intestinal permeability (lipopolysaccharide binding protein [LBP] and soluble cluster of differentiation [sCD14]), and the inflammatory marker interleukin (IL)-6. RESULTS: NWO-O had higher percent, absolute, and trunk fat compared to NWL-Y and NWL-O (p's ≤ 0.01). Conversely, percent lean mass was lower in NWO-O versus both NWL groups (p's ≤ 0.01). NWO-O had higher fasting triglycerides than NWL-Y (p < 0.05), but all groups were in the clinically normal range on average (≤107 mg/dL). However, NWO-O had higher 4 h triglycerides (239.4 ± 101.0 mg/dL) compared to NWL-Y and NWL-O (p < 0.01), consistent with an adverse response. The absolute change in triglycerides was higher in NWO-O relative to NWL-Y (p < 0.01), but not compared to NWL-O (p = 0.06). Fasting IL-6 was higher in NWO-O relative to NWL-Y (p < 0.05). Fasting and 4 h sCD14 were similarly higher in NWL-O and NWO-O versus NWL-Y (p's < 0.01). CONCLUSIONS: NWO-O had an exaggerated postprandial triglyceride response compared to younger and similar-aged NWL individuals, which could reflect hepatic very low-density lipoprotein overproduction or impaired triglyceride clearance. Future work should continue to investigate the role of postprandial dyslipidemia in NWO-O's reported CVD risk.