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The online version of this article (doi:10.1186/1477-7525-10-18) contains supplementary material, which is available to authorized users.
The authors declare that they have no competing interests.
GJ conceived of the study, participated in its design and coordination, supervised the statistical analysis and wrote the final manuscript. NJ, IH, IV participated in data collection. TH participated in designing and coordinating the study and revised the manuscript. All authors read and approved the finale manuscript.
Shift workers may be at risk of different diseases. In order to assess cardiometabolic risk in shift workers, a cross-sectional study was performed among active workers.
A total of 481 workers (121 men, 360 women) were investigated; most of them were employees in light industry (58.2%) or in public services (23.9%). Past medical history was recorded and physical examination was performed. Questionnaires were used to characterize daily activity. Fasting venous blood sample was collected for measuring laboratory parameters. Data from shift workers (n = 234, age: 43.9 ± 8.1 years) were compared to those of daytime workers (n = 247, age: 42.8 ± 8.5 years), men and women were analyzed separately.
In men, systolic blood pressure was higher in shift workers compared to daytime workers (133 ± 8 vs 126 ± 17 mmHg; p < 0.05). In women, weight (73.6 ± 15.5 vs 67.7 ± 13.2 kg; p < 0.001), body mass index (27.5 ± 5.7 vs 25.0 ± 4.3 kg/m2; p<0.001) and the prevalence rate of hypertension in the past medical history (24.4 vs 13.4%; p < 0.01) were higher in shift workers compared to daytime workers. In addition, the proportion of current smokers was higher (37.7 vs 21.7%; p < 0.001) and HDL-cholesterol level was lower (1.56 ± 0.32 vs 1.68 ± 0.36 mmol/l; p < 0.01) in female shift workers than in female daytime workers. Both in men and in women, rotating shift workers spent less time sleeping both on working days and on non-working days, spent less time with sport activity, drank more coffee and they spent less time working per day, especially in light physical work, compared to daytime workers. In addition, low and middle educational levels were most frequently found among rotating shift workers as opposed to the daytime workers where high educational level was more common.
Middle-aged active shift workers, especially women, have a less healthy lifestyle and are at higher cardiometabolic risk as compared to daytime workers. Our study highlights the importance of measures for identifying and preventing cardiometabolic risk factors in shift workers.