Effect of night shift work on the control of hypertension and diabetes in workers taking medication

BACKGROUND: Night shift work induces physiological and psychological stress by altering sleep and biological rhythms and is associated with hypertension, diabetes, obesity, and cardiovascular diseases. Few studies have been conducted on the control of hypertension and diabetes. This study aimed to examine the effect of night shift work on the control rate of hypertension and diabetes. METHODS: Subjects comprised workers aged 20–65 years who underwent specific health examination at a single facility in seven different affiliated examination centers from 1 January to 31 December 2016. Workers were categorised into day workers and night shift workers. Demographic and medical history were taken, and physical examination was done. Blood pressure (BP) and fasting glucose were measured. The control rate of each disease was evaluated based on treatment goals presented in the treatment guidelines of the Korean Society of Hypertension and the Korean Diabetes Association (systolic BP < 140 mmHg and diastolic BP < 90 mmHg; fasting glucose ≤ 130 mg/dL). RESULTS: Among 631,418 subjects, 11.2% (70,450) were night shift workers. Of whom 6.1% (4,319) were taking antihypertensive medication and 2.5% (1,775) were taking diabetes medication. Among patients taking antihypertensive medications, the proportion of those whose BP was controlled to suit treatment goals was 81.7% (26,635) of day workers and 77.4% (3,343) of night shift workers, which was significantly different (p < 0.001). Among patients taking diabetes medications, the proportion of those whose blood glucose was controlled to suit treatment goals was 37.4% (4,489) of day workers and 36.5% (647) of night shift workers, but the difference was not significant. The control rates for patients taking antihypertensive medications (odds ratio [OR]: 0.74, 95% confidence interval [CI]: 0.68–0.80) were lower among night shift workers than day workers with adjustment for age, sex, smoking history, alcohol consumption, exercise, and obesity. However, there were no differences in control rates for patients taking diabetes medications (OR: 0.99, 95% CI: 0.87–1.10) between day workers and night shift workers. CONCLUSIONS: Night shift work can have an effect on the uncontrolled BP in workers taking antihypertensive medications. Therefore, additional efforts for disease control are necessary for night shift workers with hypertension.