Grandchildren may be adorable, but the little blighters are a handful as well – and a new study thinks that may work towards the survival of our species. A study from the Women’s Health Ageing Project in Australia found that postmenopausal women who spent one day a week looking after their grandchildren could have a reduced risk of developing cognitive diseases such as Alzheimer’s  – and the benefits of having grandchildren may not be confined to women.
We’ve been aware that humans have what could be considered (biologically speaking, of course) a redundantly long life-span – given that most mammals die shortly after they cease to be capable of reproduction. There are many reasons why people’s life spans have been increasing – better medical care, a fuller understanding of nutritional requirements, better work & safety procedures in the workplace and a reduction in smoking, to name but a few – but a recent study published in the Proceedings of the National Academy of Science points to a new potential explanation for our longevity.
The study identified several genes in humans that protect against neurodegenerative and cerebrovascular diseases (the latter being conditions which are caused by problems that affect blood supply to the brain) . Moreover, these genes aren’t present in other primates – they’re only found in humans. The study highlights the historic benefits of having active (or “foraging”) elder individuals around to help provide for the family, and points to this as a potential reason for these protective genes to exist. Therefore, having genes which prevent decline in old age means that grandparents are able to help provide for young children, rather than becoming an “extra baby” (to quote Dr. Ajit Varki, the senior author on the study).
To put it simply, the conclusion the study seems to point to is that these genes exist to promote a longer period of healthy life where grandparents can contribute, rather than simply to prolong the human lifespan irrespective of the health a person may be in. This isn’t quite the same as saying having grandkids necessarily makes you live longer, of course, though a number of studies, such as the one from Women’s Health Ageing Project in Australia, do imply the social benefits of having grandchildren may confer some cognitive benefit.
The benefit, however, appears to be capped – older ladies who engaged in childcare five days a week or more were actually more likely to suffer neurodegenerative disorders  – so remember that the next time your daughter is trying to dump the grandkids on your doorstep for the third day in a row! And another study indicates that a good grandparent-to-grandchild relationship is linked to lower depression symptoms in both  – although this study was conducted on young adult grandchildren, so if minding your grandkids in their terrible twos makes you feel like putting your head through a wall, don’t worry, that’s still legitimate.
Overall, many happy granddads can attest to the positive benefits of having grandchildren – they may keep you more active, you may feel less socially isolated (and older people who are socially isolated run an increased risk of death ), and interacting with them may simply make you happier, which certainly can’t do any harm – but whether or not you can thank your grandkids for the protective genes which give us humans a longer healthy lifespan will require more investigation to determine.