Dear site’s visitors! A couple of weeks ago our administrator turned to me with an unexpected request. He asked me to choose a topic for the next article, by myself. Of course, he had a couple of requirements (on the other hand, let’s erase the last word…), sorry, recommendations. Firstly, the topic should be interesting to you, our readers; secondly, the topic should be very kind and heartwarming; thirdly, it should be relevant to the policy of our site, and fourthly, not boring. After a short brainstorm over the administrator’s request, I realized that it was too early for me to be glad about the administrator’s unexpected democracy. In fact, he left me no choice …
So, today’s topic is about grandmothers, our wonderful grandmammas! And, a little bit about grandfathers!
As a lyrical digression (especially for linguistics’ lovers): what language the word “grandmother” does not translate into, there will always be some kind, warm, and even tasty feelings in this word. Please listen: “grandmamma”, “nonna”, “savta”, “kupuna”. Am I wrong?
And now, let’s get down to business.
In a study published in 2004 (Lahdenperä et al. Fitness benefits of prolonged post-reproductive lifespan in women. Nature. 2004; 428 (6979): 178-81), the correlation between the rate of children survival and their care by grandmothers was examined. The researchers studied family records in church books over almost 150-year period in Canada and Finland. In Finnish families, where 50-75-year-old grandmother from the maternal side took care of children, the child mortality was 29.5 percent lower than in “grandmother-lacked” families. The presence of a maternal grandmother in a Canadian family increased the survival of children by an average of 1.14 children. These results have been confirmed by further studies (e.g., Chapman SN, Pettay JE, Lummaa V, Lahdenperä M. Limits to Fitness Benefits of Prolonged Post-reproductive Lifespan in Women, Current Biology 2019, 29 (4): 645-650).
But there is, unfortunately, the “flip” side of the coin:
Lau et al. (Child Obes. 2019; 15 (1): 14-20) found a direct correlation between the elevated percentage of New York children (2-19 years old) with increased weight and the fact of their care by grandmothers (and/or grandfathers). Note that the examined children were of Chinese origin. A similar positive correlation was also found in China (He et al. Econ Hum Biol. 2018 29: 56-63). Moreover, a large meta-analysis of such studies (analyzing 23 studies conducted in nine countries) does not give an unambiguous conclusion, but it has found an increase of almost 30% in the risk of childhood obesity in families where the parents raise their children in grandparent-independent manner (An et al. Child Obes 2020 16 (3): 141-153).
Probably, it would be necessary to discuss these works, the pros and cons from the point of view of science of excessive love for grandchildren, or to talk about the evolutionary hypothesis that natural selection helps to increase life expectancy after the end of the reproductive period as helping the offspring to multiply successfully (so-called the “grandmother effect”). But, frankly, I want to keep such a warm and tender mood… However, for those who are interested in learning more, I can recommend the works of Hawkes. Human longevity: the grandmother effect. Nature. 2004 Mar 11; 428 (6979): 128-9, and of Lynch et al. Evolutionary significance of maternal kinship in a long-lived mammal. Philos Trans R Soc Lond B Biol Sci. 2019; 374 (1780): 20180067.
Our dear grandmothers (and grandfathers, of course, too)! Thank you for everything!!! We miss you very much!!!
Featured image by FuSuSu . from Pixabay.