Employment status, non-daytime work and gastric ulcer in men.

BACKGROUND

An excess risk of gastric ulcer (GU) (ICD-8: 531) has formerly been found in shift workers and ex-shiftworkers but little is known about the risk of GU associated with other forms of non-daytime work. This study deals with associations between non-daytime work and GU.

METHODS

A fixed cohort of 122,116 men in occupations in which at least 20% had non-daytime work and a reference group of 593,281 men in occupations with daytime work only, was followed in the National Inpatient Register for first discharges with GU as the principal diagnosis.

RESULTS

For men with daytime work only we found a steep inverse association between GU and employment status. Men in occupational groups with late evening work had a standardized hospitalization ratio (SHR) of 236 (90% confidence interval [Cl]: 184-299), groups working in rosters covering 24-hour services had an SHR of 147 (90% Cl: 116-183). A slightly raised risk of 114 (90% Cl: 101-128) was found in groups having other forms of non-daytime work. For all men in groups with non-daytime work we found a significant SHR of 130 (90% Cl: 118-142).

CONCLUSION

We conclude that both low employment status and non-daytime work are associated with an increased risk of GU.