Haemoglobin and anaemia in a gender perspective: the Tromsø Study

To examine the gender-specific distribution of haemoglobin (Hb) and the World Health Organization (WHO) criteria for anaemia compared with the 2.5 percentile for Hb.

A population-based study from Tromsø, Northern Norway. All inhabitants above 24 yr were invited. In total, 26 530 (75%) had their Hb analysed.

The 2.5-97.5 percentile of Hb was 129-166 and 114-152 g/L for all men and women, respectively. In men, mean Hb decreased from 148 to 137 g/L between 55-64 and 85+ yr. In women, mean Hb increased from 132 to 137 g/L between 35-44 and 65-74 yr and then decreased to 131 g/L among the oldest. Using the WHO criteria for anaemia (Hb: <130 and <120 g/L, men and women respectively), the prevalence of anaemia in men increased with age from 0.6% aged 25-34 to 29.6% aged 85+. For women, the prevalence of anaemia varied from 9.1%, 2.2% and 16.5% in the age groups of 35-44, 55-64 and 85+ yr, respectively. The WHO criteria gave a two to three times higher prevalence of anaemia compared with the 2.5 percentile of Hb in women, but the difference was small in men. Poor self-rated health was not associated with low values of Hb in women. In men, there was an association in some age groups.

The WHO criteria for anaemia and the 2.5 percentile for Hb corresponded well for men, but not for women. The WHO criteria of anaemia may result in medicalization of healthy women.