A Possible Explanation of the "Obesity Paradox"
Copyright 2011, James Michael Howard, Fayetteville, Arkansas, U.S.A.
The "obesity paradox" is a phenomenon characterized by reduced morbidity in obese and overweight people compared to leaner people, that is people with more normal body mass index (BMI).
It is my hypothesis that obesity is caused by low DHEA. In my other essays, I have considered the connection of testosterone and DHEA. Testosterone ultimately reduces the availability of DHEA by reducing conversion of DHEAS to DHEA; DHEAS is the precursor of DHEA so increased DHEAS may mean lower DHEA. In the medical literature, high testosterone is often found with high DHEAS. (Testosterone dominates DHEA. For sake of interest and support, I think human evolution is caused by an increase in testosterone ("Androgens in Human Evolution," Rivista di Biologia / Biology Forum 2001; 94: 345-362; available at: http://members.cox.net/jmhoward3/Androgens%20in%20Human%20Evolution.htm ). I think testosterone increases periodically and we are currently in one of those periods so we are seeing increased obesity and other increases in morbidity simultaneously caused by the same thing.)
I have stated for many years that I think the "secular trend" is the result of this increase in testosterone. I think this is causing an early, high increase in testosterone which results in a lower production of testosterone later in life. So, this causes increased morbidity early in our life spans as a result of too much testosterone followed by increased morbidity in ageing as a result of low testosterone.
An explanation of the "obesity paradox" may now be explained. Early testosterone reduces DHEA by increasing DHEAS which increases obesity. DHEA naturally begins to decline around the ages of twenty to twenty-five, reaching very low levels in old age. I suggest in some individuals, DHEAS levels remain higher than others. Therefore, they live longer, healthier lives. When testosterone begins to decline with age, the reduction in conversion of DHEAS to DHEA may increase for a time. In those individuals who have less DHEAS, the availability of DHEA is reduced; in those who have more DHEAS in old age, the availability of DHEA remains higher for a time. It is my hypothesis that evolution selected DHEA because it optimizes replication and transcription of DNA. Therefore DHEA levels affect all tissues. Loss of DHEA of old age results in morbidity in all tissues. Therefore, increased availability of DHEAS and reduced testosterone will, for a time, make DHEA more available and protect against morbidity of old age.
I think this may explain the "obesity paradox."