Uhm, that article says that the average life expectancy for inuit, not counting infant mortality was 43.5 years old. Sure, some of the people lived to older ages, but it's hardly the apples to apples comparison they're trying to make.
"Keep in mind that the Westerners who were developing cancer alongside them probably had a similar life expectancy at the time." I don't have figures for that exact comparison, but grabbing _A Farewell to Alms_ off my bookshelf, it's got for England, 1750-99: life expectancy at 20: 34 (i.e. living till 54). That's not dramatically different. (Looking at the graph, I think "excluding infant mortality" means to take life expectancy from age 4 instead of 20, though I haven't checked.)
Infant mortality doesn't obviously bear on how common cancer is among adults.
The question we started with: are so-called diseases of civilization caused by something about lifestyle, or is it people living longer revealing an underlying rate that's screened off by early death in the other cultures? These figures say there were plenty of older people; usually when I see the latter claim made it lumps in infant mortality. On the other hand, the reported differences in rates of things like cancer are huge.
Also, the 10 years leaves out age 4-20 mortality, if I understand it right.
