Older Parents, Probably Not So Good
One of the predictions of the reliability theory of aging and longevity is that we are all born damaged. Reliability theory evolved from the theories used to predict failure in mechanical systems; as such, it is a less an attempt to explain the roots of aging and more an attempt to frame an understanding of the way in which accumulating damage at the most fundamental levels of our biochemistry produces the observed patterns of aging.
The models of reliability theory only match up with reality if we assume that life starts with a certain level of preexisting biological damage, and that damage goes some way to determining later health and life expectancy. What happens in early life matters a great deal, it seems. This is why we are interested in such topics as the potential effects of solar radiation on the unborn, and the degree to which historical increases in longevity can be explained by a lower childhood burden of chronic disease.
I noticed another interesting data point today in an open access paper: a possible marker for the biological cost of being born to an older mother - something that we know bears an increased risk of health issues.
Parental ages and levels of DNA methylation in the newborn are correlated:
Changes in DNA methylation patterns with age frequently have been observed and implicated in the normal aging process and its associated increasing risk of disease, particularly cancer. Additionally, the offspring of older parents are at significantly increased risk of cancer, diabetes, and neurodevelopmental disorders. Only a proportion of these increased risks among the children of older parents can be attributed to nondisjunction and chromosomal rearrangements.We found that methylation levels [associated with] 142 genes were significantly correlated with maternal age. A weaker correlation was observed with paternal age. ... Genes associated with [cancer] are significantly over-represented among the genes correlated with maternal age, and this suggests a link to known increased risks of cancer among the children of older parents. Similarly, gene functions related to neurodevelopment and neuroregulation are over-represented among the strongly correlated genes, and this may have relevance to the increasing risk of neurodevelopmental and psychiatric disorders in offspring as parental ages increase.
Biotechnology will be a great leveler of opportunity, a grand remover of adversity, offering the chance to repair deleterious consequences of ancestry, birth, and other biological circumstances beyond our control. Systematic alteration of DNA methylation will likely be a commonplace medical technology of the late 2020s, for example. This and many other potentially beneficial manipulations of DNA are almost within reach of the most advanced research groups today - and the biotechnologies of ten or fifteen years from today will far cheaper and more capable than the best machinery now available.
Since diet, nutrients, and additives like bisphenol A cause methylation changes that persist across generations, it would be interesting to know how much of hereditary longevity is genetic vs. epigenetic.
The thing about the word 'significant' when used in the context of statistics is that it merely means that the results were distinguishable from random chance, it doesn't mean that the results are quantifiable significant to a standard that anyone would care about. I see nowhere in this report an attempt to quantify the percentage increase in Methylation level for a 20 something birth mother to a 30 something birth mother. To me the study reads like just another academic wheel spinner trying to secure their next grant or assignment (something I could say about better than 80% of studies that I have read). Furthermore, the 15% frequency of (admitted) smoking during pregnancy seems very high to me, and there is no discussion of how the participants were selected. I have to question the veracity of data resulting from what is most likely a self selected group of women whose health care options are so limited that they most likely had to resort to participating in this research Health study in order to obtain health care for their unborn child.