It's not because of the low melanin levels per se; it is because of sun damage to which people with lower melanin levels are more prone. So if you have, eg, been slapping on the sunscreen ever since you read an article in She back in 1992 about how 90 per cent of the skin damage we associate with ageing is in fact sun damage, you'll have circumvented that.
Genes help, though. I reckon genes are most of it.