IRON STATUS IN DANISH WOMEN AGED 35-65 YEARS - RELATION TO MENSTRUATION AND METHOD OF CONTRACEPTION

Iron status was assessed by serum (S-) ferritin and hemoglobin (Hb) in a population survey comprising 883 non-gravid Danish women in age cohorts of 35, 45, 55, and 65 years. Premenopausal women (n = 676) had lower S-ferritin, median 42 mug/l, than postmenopausal women (n = 207), median 80 mug/l (p < 0.0001). Of premenopausal women, 12.1% had S-ferritin less-than-or-equal-to 20 mug/l (i.e. depleted iron stores), and 35.6% S-ferritin of 21-40 mug/l (i.e. small iron stores). Corresponding figures in postmenopausal women were 0.5% and 13.2%. Premenopausal blood donors (n = 88) had lower S-ferritin than non-donors (p < 0.001). In premenopausal women, S-ferritin levels were strongly dependent on the duration of menstrual bleeding (p < 0.0001), which in turn was related to the method of contraception. Women (n = 64) using hormonal contraceptives (the pill) had menstrual bleeding of shorter duration than those (n = 511) not using pills or intrauterine devices (IUD), who in turn had bleeding of shorter duration than those (n = 101) using IUD. Median S-ferritin in pill users was 62 mug/l, in those not using pills or IUD 42 mug/l, and in IUD users 36 mug/l. S-ferritin values < 40 mug/l (i.e. small and depleted iron stores) were seen in 25% of pill users, in 48% of those not using pills or IUD, and in 61% of IUD users. Hb values in premenopausal women were mean 134 +/- 10 (SD) g/l (8.3 +/- 0.6 mmol/1), median 132 g/l (8.2 mmol/l), being slightly lower than in postmenopausal women, mean 137 +/- 10 g/l (8.5 +/- 0.6 mmol/l), median 135 g/l (8.4 mmol/l) (p < 0.001). Iron deficiency anemia (i.e. S-ferritin less-than-or-equal-to 20 mug/l and Hb < 121 g/l) was found in 3.0% of premenopausal and in none of postmenopausal women.