August 16, 2012: I must amend this explanation.  I now think that the testosterone to DHEA ratio is very important.  That is, I think testosterone is in decline along with DHEA during aging, starting about age 25.  I think testosterone evolved to increase the functionality of DHEA by increasing androgen receptors, through which DHEA enters cells to activate genes.  Since I think the secular trend not only increases testosterone excessively during youth, this early peak of testosterone results in an earlier decline of testosterone as we age in individual in whom this occurs.  Therefore, aging now includes declines in testosterone which reduces androgen receptors which exacerbates the natural decline of DHEA.  So, the increase in atrial fibrillation, I suggest, is caused by both the decline of testosterone and DHEA.  The increase in incidence would still be due to increases in testosterone within the population but the effect of testosterone is caused by the earlier decline of testosterone as a consequence of the early rise in testosterone.  (If interested, see: “DHEA, Estradiol, Testosterone, and the Relevance of Their Ratio …The Androgen Receptor …and the Secular Trend,” at: .)


Increasing Testosterone, the “Secular Trend,” may be Increasing Atrial Fibrillation


Copyright 2006, James Michael Howard, Fayetteville, Arkansas, U.S.A.


“This study confirms previously observed trends of increasing AF [atrial fibrillation] prevalence…” Heart 2005; DeWilde, et al.


It is my hypothesis that the "secular trend," the increase in size and earlier puberty in children, is caused by an increase in the percentage of individuals of higher testosterone over time within the population.  It is also my hypothesis that "atrial fibrillation" is caused by low DHEA.  The incidence of AF increases with age; DHEA naturally begins to decline around age 20 reaching very low levels in old age.  There are also indications that anabolic steroids may trigger AF.  Testosterone may be shown to increase DHEAS, the source from which DHEA is converted.  Higher DHEAS may indicate that DHEA is low.  Conversely, if DHEAS is low, DHEA may also be low as less is converted from low DHEAS.  Low DHEAS has been connected with atrial fibrillation (Exp Gerontol. 2002 May;37(5):701-12).


I suggest the reason atrial fibrillation is increasing may be due to an increase in the percentage of individuals of higher testosterone and, therefore, the adverse effects on levels of DHEA.  As DHEA levels decline in the population, atrial fibrillation may be increasing with time.




In humans testosterone increases in autumn and winter and testosterone is higher in men than women.  The connection of testosterone and low DHEA, that is DHEA is very low in old age, and atrial fibrillation is directly supported in the following report.


Seasonal variation in morbidity and mortality related to atrial fibrillation” Int J Cardiol2004 Nov;97(2):283-8


“Between 1990 and 1996, there were a total of 33,582 male and 34,463 female hospitalisations related to AF. Significantly more admissions occurred in winter compared to summer (P<0.0001). In women, the peak number of admissions (106 per day) occurred in December (12% more than average) and the lowest number (89) in June (6% less than average). The respective figures for men were 10% more (101), 2% less (90). In both sexes, the greatest variation occurred in those aged >85 years—peak winter rates being 35–39% higher than average. A similar phenomenon was evident in relation to mortality in these patients. The average number of men who died during December was 22% higher, and in August 12% lower, than average, P<0.001. In women, the equivalent figures were 28% higher (December) and 14% lower (August), P<0.001. The winter peak of AF admissions did not, however, coincide with the lowest temperatures, and other factors such as seasonal variation in respiratory infection, may account for the monthly variation observed in hospitalisations for AF.”