Endocrine Abstracts

Background: A higher cardiometabolic risk has been reported in night shift workers. Post prandial hypertriglyceridemia (PPHTg) is recognized as an independent cardiovascular risk marker. Few studies have shown that acute disruption of circadian rhythm is followed by significantly altered insulin secretion and lipid tolerance.

Aim and objectives: In this study we compared the postprandial triglyceride (PPTG) responses to standard oral fat meal between health care night shift workers and non- night shift workers to ascertain if it contributes to cardiometabolic risk in them.

Methods: 20 health care night shift workers (≥4 night duties/month for last one year), aged 20–40 years with normal glucose tolerance (NGT) following a 75 g glucose OGTT and 20 age and sex matched non-night shift workers who had not done night duty in the last one year or ever were recruited. Anthropometric, OGTT, HbA1c (%), insulin, HOMA-IR, HOMA-β (%), fasting lipids parameters and inflammatory markers (IL-6 & Hs CRP) were measured. PPTG responses were obtained after a standard fat meal given at 8 am, and sampling done every two hours for next 8 hours, that is at 0, 2, 4, 6 and 8 h and compared between the two groups.

Results: Night shift and non-night shift workers were matched for age (29.70±3.92 years vs 29.70±2.23 years) and sex (M:F 12:8 vs 12:8). The duration of night shift exposure was relatively short (4.2±3.3 years) among cases. There was no significant difference between the two study groups with respect to anthropometric, glycaemic, fasting lipids parameters or inflammatory markers. However, 2 h postprandial glucose in health care night shift workers was comparatively higher than non-shift workers (103.8±18.53 mg/dl vs 91.5±19.96) though it just fell short of statistical significance (P=0.50). PPTG measures – PPTG area under the curve (TG AUC) and TG peak values were comparable in both the groups. PPTG response showed significant positive correlation with fasting insulin and HOMA-IR indicating insulin resistance, and HOMA-β (%) indicating insulin secretion in night shift health care workers but not in others. There was no significant correlation of PPTG parameters with any other clinical, biochemical and inflammatory measures.

Conclusions: Postprandial triglyceride burden is significantly associated with insulin resistance in night shift workers even with a relatively short duration of night shift,