BACKGROUND: Shift work is associated with coronary heart disease (CHD). Metabolic syndrome (MS) is associated with an increased risk of cardiovascular disease (CVD). An association between shift work and MS has been reported in some studies.
OBJECTIVE: The purpose of this study was to compare the criteria of the National Cholesterol Education Panel (NCEP), revised NCEP (NCPEP-R) and International Diabetes Federation (IDF) metabolic syndrome criteria for the diagnosis of MS, also to explore how metabolic risk factors for CVD differ between shift workers and day workers in a cohort of Italian workers.
METHODS: The study population consisted of 552 workers (361 men, 191 women; mean age 40.4 years) and included 262 healthcare providers (130 rotating shift nurses and 132 day nurses), 204 forestry workers and 86 factory workers. Fasting blood sugar level, HDL-cholesterol, triglycerides, blood pressure, and waist circumference were measured.
RESULTS: Healthcare providers had greater waist circumference (p< 0.01), serum triglycerides (p< 0.01) and fasting plasma glucose (p< 0.001) compare with the other worker categories. In comparison with day workers, rotating shift nurses had greater waist circumference (p<0.001), higher serum triglycerides (p< 0. 001) and fasting plasma glucose (p< 0.05), and lower concentrations of HDL cholesterol (p<0.01) The prevalence of MS according to NCEP criteria was 8.3%, according to NCEP-R criteria 9.3% and 12% according to IDF criteria. No significant association between MS and shift work was found. Abdominal obesity and high serum triglycerides was significantly associated with shift work after adjusting for age, sex, smoking, alcohol consumption and job seniority, with an OR of 2.74; 95% CI: 1.43-5.26 for high serum triglycerides and an OR of 1.81; 95% CI: 1.0-3.2 for abdominal obesity assessed according to IDF criteria. No significant association with NCEP and NCEP-R criteria was observed.
CONCLUSIONS: The data show greater prevalence of cardiovascular risk factors among healthcare providers. Shift work was significantly associated with high triglycerides and abdominal obesity using IDF criteria. Measurement of waist circumference is a simple and non-invasive method to use in the evaluation of metabolic risk factor for CVD.
