You might recall the reliability theory of aging and longevity, with its implication that we are born with a surprisingly high level of existing damage, reducing our life span. There is also the relationship between solar radiation during pregnancy and resulting life expectancy. Here's a paper speculating on the mechanics that might link early environmental circumstances with the odds on life span: "Recently a cluster of new hypotheses of aging has been suggested, which explicitly predict the importance of early-life events in health and life span modulations. It has been widely assumed that these long-lasting consequences of early-life exposures may depend on the same mechanisms as those underlying 'cellular memory,' that is, epigenetic inheritance systems. There is a growing body of evidence that environmentally induced perturbations in the epigenetic processes (which involve alterations of gene expression without a change in DNA sequence) can determine different aspects of aging, as well as [cause and course] of age-related diseases."