[48] Tarzia P, Milo M, Di Franco A, Di Monaco A, Cosenza A, Laurito M, Lanza GA, Crea F. Effect of shift work on endothelial function in young cardiology trainees. Eur J Prev Cardiol. 2012 Oct;19(5):908–913. doi: 10.1177/1741826711422765. Epub 2011 Sep 7. PMID: 21900367. RefID—495 PMID—21900367
Study Setting	Department of Cardiovascular medicine, Catholic University of the Sacred Heart, Rome, Italy.
Eligible Participants	Healthy cardiology trainees affiliated with the university hospital.
Study Aims	This study assessed the acute effect of night work on endothelial function in young medical doctors without any apparent cardiovascular risk factor.
Study Design & Participants	This observational study design involved 20 healthy cardiology trainees without cardiovascular risk factors. These trainees have a history of shift work of 24 ± 12 months and average of 3–4 nights and 1–2 weekend shifts a month. The assessment of the endothelial function was taken at two separate times: one after a working night and another after a restful night. The two sessions were performed in random order. Study supervisors observed the trainees on a regular workday from 8:30 a.m. to 4–6 p.m., while night shifts were observed from 8 p.m. to 8 a.m.
Intervention	The trainee could rest or sleep during shift, when no medical intervention was required, in a dedicated room.
Comparison(s)	After a working night, endothelial function with FMD was captured among trainees. Trainees during a working night in which they obtained rest/sleep were compared to trainees during a restful night.
Outcome Measure(s)	FMD: Subjects rested in a supine position for at least 10 min in a warm, quiet room (22–24 °C) before being tested. A 10 MHz multifrequency linear array probe attached to a high-resolution ultrasound machine was used to acquire images of the right brachial artery. After baseline images of the right brachial artery were obtained for 1 min, a forearm cuff—positioned 1 cm under the antecubital fossa—was inflated to 250 mmHg. The cuff was released 5 min after the inflation to induce forearm reactive hyperemia. Brachial artery diameter was analyzed using automated edge-detection software. Outcomes reported as FMD are seen in Figure 1 and Table 2.
Key Finding(s)	The difference in FMD between WN and RN was not influenced by the number of hours slept during WN. FMD was 8.02 ± 1.4% and 8.56 ± 1.7% after WN and RN, respectively (p value 0.025). As seen in Table 1., FMD when trainees had <4 h of sleep during shift was 8.57, while >4 h of sleep during shift was 8.66 (p-value = 0.5), as seen in Table 2.