night shifts in the current work schedule and the total duration of night shift work. Results Chronic back pain, hypertension and thyroid disease were the most common diseases in the total population of nurses and midwives. The prevalence of thyroid disease was higher than in the general population of Polish women (21.2% vs. 10%) and the relative risk of this disease increased with increasing duration of night shifts work. The analysis did not show significantly higher frequency of any disease

more »

... r symptom in the night shifts nurses compared to the day workers. The analysis showed significantly increased risk of feet swelling in women working 8 or more night shifts per month (OR = 8.55; 95% CI: 1.02-71.80). Conclusions We did not find significant increased risk of any of the diseases or symptoms among night shifts nurses than among the women working only during the day. The increased prevalence of thyroid disease among the women with long duration of night shift work warrants further epidemiological studies.