Serum ferritin in a Greenlandic Inuit hunter population from the Thule district

Serum (S-) ferritin was analyzed in 67 Greenlandic Inuit hunters from Thule (Qaanaaq), 35 males and 32 females with a median age of 39 years (range 17-77). S-ferritin was higher in males, median 211 micrograms/l (range 30-1040), than in females, median 87 micrograms/l (range 33-794) (p less than 0.01). None of the subjects had S-ferritin less than or equal to 20 micrograms/l (i.e. depleted iron stores); 5 of the 48 subjects less than or equal to 50 years old had S-ferritin 21-40 micrograms/l (i.e. small iron stores). All 19 subjects greater than 50 years old had S-ferritin greater than 40 micrograms/l (i.e. replete iron stores) and 8 showed values greater than 300 micrograms/l (i.e. increased iron stores). S-ferritin levels increased with the percent energy intake from traditional native hunter food (rs = 0.26, p less than 0.05). Inuit had higher S-ferritin than Danish Caucasian subjects. In Inuit of both sexes, S-ferritin displayed a correlation to age (rs = 0.63, p less than 0.0001 in the entire series), indicating gradually increasing S-ferritin levels during lifetime, without the plateaus seen in Caucasians. These findings suggest continued accumulation of iron reserves in elderly Inuit, due to consumption of large quantities of iron rich meat from marine mammals and/or genetic differences in the regulatory mechanisms for body iron stores.