Sex difference in cardiac performance in individuals with irregular shift work

Background: sex differences existed in animal behavioral adaption and activity rhythms when exposed to chronic disruption of the circadian rhythm. Whether these differences extend to cardiac performance has not been fully investigated by cardiac imaging technology.

One hundred and thirty patients enrolled in this study. Patients were divided into the day shift (DS) group and the irregular shift (IRS) group based on whether involved in the night shift and the frequency of the night shift. Comparisons of clinical data and cardiac imaging parameters were performed to identify the sex difference in cardiac function in the participants with day shift work or irregular shifts.

The absolute value of GLS was significantly lower in male IRS group than in male DS group. In females, no significant difference was tested in left ventricular function between the two groups. In male participants, Weekly work hours (WWH) was positively correlated with HR (r = 0.51, p = 0.02) and QTc duration (r = 0.68, p < 0.00), and weakly negatively correlated with the GLS (r = -0.38, p = 0.05). Amongst patients, there was a 2.67-fold higher relative risk (RR) for impaired GLS in males than in females, with a 95 % confidence interval (CI) of 1.20-5.61. Moreover, there was an increased risk in the male IRS group compared to the female IRS group to develop impaired GLS (RR:3.14, 95 % CI 1.20-7.84).

The present study suggests that chronic circadian disruption brings cardiac dysfunction in people with night-shift work. Gender differences exist in the impact of circadian rhythmicity on cardiac function and may help to guide the work schedule and breaks in shift workers and bring forward prevention strategies in response to chronic circadian disruption.