New theory for global diabetes epidemic

A new "fertility first" hypothesis published this week by a group of international experts in the American Journal of Human Biology, proposes that the global epidemic of Type 2 diabetes has its origins in the struggle, over millennia, to sustain human fertility in environments defined by famine.

A surprising and important implication for us in the modern world is that this hypothesis gives cause for optimism that the modern epidemics of diabetes and cardiovascular disease will diminish.

"If we are right, rapid human evolution should, in decades rather than centuries, reduce the prevalence of the conserved ancestral genes which underpin these conditions," said Associate Professor Stephen Corbett from the University of Sydney, one of the study's authors.

The key piece of evidence in support of this idea comes from a close look at a condition closely related to Type 2 diabetes, the Polycystic Ovary Syndrome (PCOS). This condition is globally the most common cause of ovarian infertility and its very existence is a paradox because evolutionary theory would predict that a genetically based condition which reduces fertility would quickly erase itself.

In women with PCOS fertility declines with increases in body weight and improves with weight loss. It is this property in particular which suggests that PCOS may be associated with a fertility advantage, rather than disadvantage in women who are undernourished. "We have called this the Fertility First genotype because for much of human history these genes, if present, enabled hungry and undernourished people to continue to reproduce in lean times," Associate Professor Stephen Corbett said.

However, since the Industrial Revolution, improvements in nutrition and increases in body weight for a human majority have flicked an evolutionary switch. "The long standing fertility advantage of this Fertility First genotype has been turned on its head, and it is now a disadvantage, and should become less common," he said.

The authors this paper are Associate Professor Stephen Corbett from the University of Sydney and Sydney West Area Health Service, Professor Tony McMichael from the Australian National University in Canberra and Professor Andrew Prentice from the MRC International Nutrition Group at the London School of Hygiene and Tropical Medicine.

Their article, Type 2 Diabetes, Cardiovascular Disease and the Evolutionary Paradox of the Polycystic Ovary Syndrome: A Fertility First Hypothesis goes on line this week in the American Journal of Human Biology 2009.


  1. Uncle B Uncle B Canada says:

    We are witnessing the "Fatted Calf" syndrome! Remember, our wisdom books said,"Blessed are the meek for they shall inherit the earth", We the type 2 Diabetes sufferers are the force fed product of a corrupt society based on Capitalism's notion of ever-increasing output. We were raised to super-perform on uber-rich diets, and our bodies rebelled and quit absorbing huge amounts of insulin. Left to our natural inborn rates we would be a smaller, slower and over the long haul, more productive and efficient folk. As it stands, we are "stoked" on sugars, fats and caffeine, and expected to reach far beyond our natural propensities. We are also totally dependent on the American system as it stands, should it fail, or even falter, we will perish in a fire of pepped up metabolisms facing shortages of calories! In fact, if world trends favoring the low calorie diet of Asians and the growing strength of the 'Yuan' as a world currency of commerce is any indication, we are the product of an age gone by, and soon to perish early due to the idiotic premise of this system, that "bigger is better". Large-bodied Americans carry only one very expensive to operate brain, the same weight in Asians equals two complete individuals or more, and economical units at that! The days of the large muscled and very physically powerful 'Farm hand' are gone, and we enter a new age for humanity where mental skill and agility are most desirable, in offices, on factory floors, and even in the new hydraulically assisted, computer driven Korean ship-yards, this is so! Heavy industry no longer demands masculine brawn and physical endurance, they are looking now, for intelligence, regardless of sex, mental agility in place of endurance for unspeakable conditions, and educated minds in place of brutal self-denying tolerance for abuse. America, your work force of big lugs, bullies, Union members with huge biceps and small minds has been epoched, and obsoleted and you are stuck with a very expensive large bodied, thick minded breed that eat too much, expect abuse at the hands of the capitalists, and will die off early of diabetes high blood pressure and obesity and suffer unemployment, loss of face, and feel shame for not being able to contribute! Asia, with its smaller bodied, shorter lived, faster agile and more reproductively controlled population will excel in this new age where the computer interfaces with hydraulics and electrical might and the old industrial age's ways.

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
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