The consequences of increasing adult prevalence of chronic diseases linked with obesity on the “grandmother effect” at EvoDemoS2023

ECHO researcher Néstor Aldea will be next Friday 31st March at the Evolutionary Demography Society 8th Annual Meeting. He will present the work jointly carried out with ECHO IP Alberto Palloni: “The consequences of increasing adult prevalence of chronic diseases linked with obesity on the grandmother effect 

The “grandmother hypothesis” was proposed to explain the emergence of menopause in human females. Menopause would liberate older females to provide support for their kin. Thus, children would benefit from grandmaternal care, resulting in diminished early childhood mortality, and improved nutritional status. There is empirical evidence supporting the grandmother effect in pre-modern Western populations and low-income countries, both being characterized by elevated fertility and mortality. Thus, in societies with elevated child mortality, there must be a strong association between prevalence of co-residence of grandmothers and grandchildren and the latter’s mortality risks and nutritional status.

In modern populations, however, older adults may be exposed to increased burden of disease that compromises their capacity to provide support post-menopause. Obesogenic environments are the trigger behind the explosion of child and adult obesity. The obesity epidemic has meant the rapid diffusion of adult chronic conditions linked to obesity, these pathologies resulting in increased disability and loss of healthy years of life post-reproduction. Countries most affected by these events overlap with those where the grandmother effects are suspected to be stronger.

Based on these evidence, we propose the following research question: how and to what extent the increased obesity-related burden of chronic illness and disability in adult females might affect the survival and nutritional status of their grandchildren? Can it weaken or reverse the grandmother effect in countries where it is still prevalent? In what populations is this alteration most strongly manifested?

Moreover, at the same event, he will present a research poster on “The effect of assortative mating, differential fertility, and genetic and cultural heritability on obesity trends: results from a stable-population model”

Obesity prevalence has sharply increased in the last half century, and so have chronic associated diseases, namely type2 diabetes. We know that obesity is an inheritable trait, via three mechanisms: genetic, cultural, and biological through the mother. Also, in middle and highincome countries, women with high BMI tend to produce a higher number of children, as they are distributed in lower social classes and have less years of education.

  • Does this mean that obesity will increase in the population?
  • What is the role of differential fertility and assortative mating in the evolution of obesity
  • How do genetic and cultural heritability shape obesity trends?