Absence from work in relation to length and distribution of shift hours

A retrospective study on absenteeism was conducted over 24 months among 1354 shiftworkers in the heavy sheet stamping sections of three automative plants located in the Greater São Paulo area. The schedule of the shifts was organised on a semi-continuous basis as follows: 3-fixed shifts, 3-fortnightly rotating shifts, 1 evening-night and 2 months rotating shifts. During the period of the study, 29 and 58% of the workers were on the job for less than 1 and 2 years respectively). On two shift schedules (1 evening-night shift and 2 monthly rotating shifts) the time on the job appeared as an important variable inversely proportional to the frequency of the unjustified absences. Age was also related inversely with sickness and unjustified absences on two others shift schedules: 3 fixed and 3 fortnightly shifts. The 3 fixed shift schedule had the highest sickness ratio frequency compared with the other three systems. On the 1 evening-night shift the unjustified absence frequency rate was higher than on 3 fixed shifts and fortnightly rotating shifts. The analysis of all data considering only the work periods showed that unjustified absence rates were higher in the evening than in the afternoon and night. The morning and afternoon work periods showed higher sickness absence rates than evening and night. Unjustified absences (3031 spells) represented more serious problems than sickness absences (1601 spells) at the plants studied, although the number of days lost per sickness (7505) were higher than unjustified absences (4702).

Retrospective study regarding absenteeism among shiftworkers

Fischer

1986

Health risks related to shift work

Köller

1983

163

In an oil refinery with a labour force of 1260 male blue-collar workers, 300 matched cases of permanent shift workers, day workers, and drop-outs were selected and split into four groups corresponding in age and years at work. In terms of an overall score ("health score", computed from data concerning absence due to sickness, morbidity, distribution and severity of diseases, and subjective complaints) health was found to deteriorate with age, but to a different degree in the shift and day workers. In shift workers, a steep decrease in score during the first years at work was followed by a continued slight decrease in middle age; from the age of 41 years onwards there was a further pronounced decrease in score. In day workers a stabilization in score was observed up to middle age, with a distinct decrease thereafter. The difference in health parameters between the groups was only small in younger workers (up to 12 years at work), but became striking and significant with increasing age. In the permanent shift workers an increasing health risk was clearly indicated by increases in absence due to sickness, gastro-intestinal and cardiovascular diseases and unspecific health complaints (sleep disturbances, premature fatigue). A specific kind of behaviour during illness (e.g. less readiness to consult a doctor) was also observed in the shift workers. In the permanent day workers health risks were not strictly age-related. Whereas absence due to sickness was highest in young workers, morbidity for respiratory diseases and injuries was significantly elevated in the older workers; the frequency of subjective complaints increased up to middle age and decreased thereafter. In drop-outs with considerable prior exposure to shift work, strikingly high rates of absence due to sickness and excess rates of cardiovascular diseases were observed.

A retrospective cohort study comparing complaints and diseases in day and shift workers

Angersbach¹,

Knauth²,

Loskant³

et al. 1980

104

The incidence of sickness in general did not differ between permanent shift workers and day workers, but was highest in shift workers who transferred later to day work mostly for medical reasons Furthermore, on the average, shift workers were sick for longer periods than day workers.Significantly more shift workers than day workers consulted the occupational health services about gastrointestinal complaints than day workers. Shift workers had more frequent gastrointestinal diseases than day workers and more severe ones such as peptic ulcers Gastrointestinal diseases were more frequent in the following groups of the shift workers: Young ( 21 to 25 years) and unmarried subjects, heavy smokers and subjects with a past history of gastrointestinal diseases.No differences between shift workers and day workers could be detected concerning cardiovascular diseases including myocardial infarction Psychosomatic disorders were seldom diagnosed and did not differ between shift and day workers Surprisingly, skeletal diseases including the sequelae of accidents and injuries occurred more often in the shift workers' cohort; the possible cause of this was a higher incidence of moonlightning in shift workers or other activities beside work The need for prospective follow-up studies is emphasized.