Haematological abnormalities and reference intervals in the elderly. A cross-sectional comparative study of three urban Swedish population samples aged 70, 75 and 81 years.

We compared three representative population samples aged 70 (n = 312), 75 (n = 486) and 81 (n = 404) years. Anaemia defined either as blood haemoglobin concentration below the corresponding health-related lower reference limits or according to WHO was, in the total study groups, more common at age 81. Anaemia of unknown cause was rare, but somewhat more common at age 81. Mean blood haemoglobin concentrations in subsamples without definable disorders were significantly lower at age 81 than at ages 70 and 75, whereas the lower health-related reference limits did not differ significantly. White blood cell counts tended to be lower and iron deficiency was somewhat more common at age 81. No significant differences were found in platelet counts or in the prevalence of low plasma cobalamin concentrations. These results indicate a fall in blood haemoglobin with advancing age. The arbitrary WHO criteria for anaemia are clinically applicable at age 70-81.