To identify the health effects of shift work on nurses in Assuit university hospitals .

To estimate effect of shift work on co-morbidities among nurses . To determine the shift work associated risk factors predisposing nurses to poor health outcomes and injuries.

The word 'shiftwork' is commonly used to describe irregular, odd, untraditional working hours, or working hours that are away from day work period. Shiftwork dates back to the late 1800s, as applied to guardians of old kingdoms and in the military services. After the innovation of the light, shift work expanded for nonstop production as in steel factories, iron foundries, and material plants. Approximately one-fourth of the workforce in hospitals works unusual hours (away from the traditional diurnal work period) . Shiftwork has a number of advantages and disadvantages to employers, employees, and their families. The advantages for employers include optimal use of energy, facilities, and other resources through extended capital operating time. The advantages for employees include increased income, more free time for daily activities, and saving time by avoiding traffic rush hours. Shiftwork is associated with both short-term and long-term disadvantages on physical and psychophysiological health. Short-term effects include fatigue and difficulties with sleep. Difficulties with sleep are found to be the most common complaint among shift workers. Sleep disturbances were the main reasons that led shift workers to leave night shiftwork owing to disturbed health habits compared with day workers .Gastrointestinal disorders were reported 2-5 times more commonly among shift workers than daytime workers. These disorders range from minor complaints (e.g., constipation, heart burn, distension, and disturbed appetite) to serious gastrointestinal disorders, which may develop into chronic diseases such as chronic gastritis or peptic ulcers. Shiftwork has been also linked to type 2 diabetes and obesity as sleep deprivation activates the immune system and influences glucose metabolism .

An association between shiftwork and cardiovascular diseases (CVDs) has been reported. There is a higher risk for CVD such as hypertension, subclinical atherosclerosis, and ischemic heart disease compared with daytime workers . Different types of cancer have been reported in shift workers including cancers of the breast, colon, and endometrium. Shiftwork system causes circadian rhythm disruption, which is probably carcinogenic to humans.

Also, shiftwork causes disruption in both social and domestic lifestyle, which is a major consequence of shiftwork, especially with maternal employment that may have some adverse influences on their young children's cognitive and behavioral outcomes.

Inclusion Criteria:

• Active working nurses working in Assiut University Hospitals with minimum exposure to work shift for 1 year .
• Had free pre-employment records

Exclusion Criteria:

• Nurses don't record shift work exposure.
• Nurses with less than 1 year exposure to shift work, or don't recorded shift work exposure.
• Nurses known to had autoimmune disorder or endocrinal disorder before joining job.

Active working nurses working in Assiut University Hospitals with minimum exposure to work shift for 1 year