Factors associated with the risk subclinical carotid atherosclerosis in rotational shift workers in the Arctic

Objective.To determine the most unfavorable predictors of atherosclerotic plaque (ASP) in carotid arteries (CA) in rotational shift workers in the Arctic using traditional risk factors, clinical and instrumental methods of research. Design and methods. In 2010–2012, we randomly selected 424 males aged 30–59 years from 1708 rotational shift workers at the medical unit of the gas production company “Gazprom dobycha Yamburg” (Yamburg settlement, 68ºN) and performed preventive medical examination. Subjects were divided into 2 groups according to blood pressure (BP) level. Group 1 included 294 patients with hypertension (HTN) of 1 or 2 stages > 140/90 mmHg and group 2 was comprised of 130 people with BP < 140/90 mmHg. The groups did not differ by age, total work experience in the Arctic and rotational shiftwork duration. Ultrasound examination of CA showed presence or absence of ASP and stenosis by NASCET method. In addition, we assessed traditional risk factors and performed 24-hour BP monitoring and blood tests including lipid spectrum, glucose level, creatinine. Results.ASP was found more often in subjects with HTN (group 1) than in people with normal BP in the same age group, 95 % CI 56–60 % vs 95 % CI 14–20 %, (p < 0,0001). The groups did not differ significantly in the nutritional habits (p = 0,067). At the same time, the rate of smoking (p = 0,039), low physical activity (p = 0,007), overweight (p < 0,0001) was significantly higher in group 1 compared to subjects with normal BP. According to multivariate analysis, three variables with the most significant predictors associated with ASP in CA with sensitivity 75,9 % were selected using step-by-step method: diastolic BP 24 (DBP24) (p < 0,0001), glucose (p = 0,017) and total cholesterol (p = 0,044). The linear function was obtained: F = –7,664 + 0,225 × Chol + 0,366 × Glu + 0,057 × DBP24, where the variable “Chol” is the level of total cholesterol in the blood in mmol/l; “Glu” — the level of blood glucose in mmol/l; “DBP24” — average 24-hour diastolic BP. Based on the model, we concluded that DBP24 increment by 1 mmHg increases the risk for developing ASB in CA by 5,9 %, OR = 1,059 (95 % CI: 1,033; 1,087); the increment in glucose and total cholesterol by 1 mmol/l increases the risk by 44,1 % and 25,2 %, respectively: OR = 1,441 (95 % CI: 1,084; 1,966), OR = 1,252 (95 % CI: 1,010; 1,565). Conclusions.Our data enable to determine the most unfavorable predictors of ASP in CA and can potentially serve as a guideline for early diagnosis and medical management to prevent cardiovascular diseases in rotational shift workers in the Arctic.