Factors affecting iron status in non-pregnant women from urban south Finland.

Iron status was evaluated in 446 non-pregnant urban Finnish women, aged 17-50 years. The mean results (95% ranges) for blood haemoglobin concentrations, mean corpuscular volumes (MCV) and serum ferritin concentrations were 139 g/l (121-155), 89 fl (79-97) and 28 micrograms/l (7-120), respectively. Serum ferritin was < 12 and < 20 micrograms/l in 11% and 30% of the subjects, respectively. In analyses of covariance, high frequency of menstruation, prolonged menstrual bleeding time, blood donation and use of intrauterine devices had negative effects (P < 0.05) on iron status. Dietary habits or participation in very hard physical exercise did not affect iron status. Factors predicting low iron stores were evaluated in a logistic regression analysis. Blood donation (odds ratio and its 95% confidence interval: 2.53; 1.22-4.82) and very prolonged (> or = 8 days) menstrual bleeding (4.93; 1.63-14.9) increased the likelihood for low serum ferritin, whereas daily physical activity (0.02; 0.01-0.88) and use of multivitamin and mineral supplements (0.57; 0.33-0.98) were associated with higher concentration. In conclusion, blood losses increase the risk for iron depletion, while higher physical activity (presumably because of the positive effects on energy and iron intake) may prevent iron depletion.