Shift work and chronic disease: the epidemiological evidence.

Area of Science:

• Occupational Health
• Epidemiology
• Chronic Disease Research

Background:

• Shift work, including night shifts, is suspected to elevate risks for chronic conditions like cancer, cardiovascular disease (CVD), metabolic syndrome, and diabetes.
• Existing reviews often focus on specific diseases or mechanisms, lacking a comprehensive summary of shift work's impact on overall chronic disease risk.

Purpose of the Study:

• To provide a general summary of current evidence on the association between shift work and chronic diseases.
• To critically review existing literature and recent studies on this topic.

Main Methods:

• Systematic and critical review of literature indexed in PubMed up to December 2009.
• Inclusion of manual searches of reference lists for relevant studies.
• Presentation of main conclusions from reviews and key findings from recent studies.

Main Results:

• Evidence suggests a possible link between night work and breast cancer, though not conclusive.
• Limited and inconsistent findings exist for other cancers and overall cancer risk.
• Associations between shift work and cardiovascular disease, metabolic syndrome, and diabetes are suggestive but not definitive.

Conclusions:

• Difficulty in drawing firm conclusions due to study heterogeneity in exposures and outcomes.
• Emphasis on positive but non-significant findings complicates generalizations.
• Further research is required for additional disease endpoints and diverse study populations.