First of all they prefer to be called Inuit.
Secondly the average life-span of Inuit is 45 years.
Im sure the cold has something to do with it but not as much as the diet, since they have ways to fight of the cold. The simply lack too many nutrients in their diet.
Eskimo is the appropriate term for the wide range of Arctic dwellers from western Alaska to Greenland. Inuit is a linguistic term not appropriate for all those peoples. While it's been fashionable in liberal circles to claim offense in the name of various native peoples, I'm sure if I were a non-Inuit speaking Eskimo being called an Inuit is what would offend me.
Secondly, 45 years seems pretty good for a low tech people living in such an extreme environment. The traditional Arctic diet is a marvel (low cancer, heart disease, diabetes rates) and known to be nutrient rich and complete. Modern Eskimos do have diet problems, it's due to the introduction of the modern diet. Google up a few articles about it. One things for sure, there's a lot we don't know about proper human nutrition.