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Page 3 of 4
What’s Causing Test Decline?
The final set of analyses is the most relevant and interesting. In this set, the researchers compared groups of men at the same age over different times (age-matched decline). In other words, the 65-year-olds of 1987 were compared to the 65-year-olds of 1995. Between these two representative groups, testosterone concentrations fell 11.2 percent from 1987 to 1995. This means that for every year younger a person is, his testosterone concentration is 1.2 percent less for every year’s difference when compared to his elder’s.1 If that trend isn’t corrected, by the turn of next century, America may be populated by men who resemble the anatomically correct Michael Jackson doll more closely than the GI Joe Cobra Commander. The final tally in the generational challenge (surely laden with Freudian overtures) is that our fathers and grandfathers were indeed manlier than us. The only good news from this study is that our position in the androgenic pecking order is firmly established over our sons and the kids who will date our daughters.
Having settled that, Tom Brokaw got it right when he called the World War II vets “The Greatest Generation.” It’s time to look more closely at the data and see what exactly these statistics describe, and what it might mean for us as individuals and as members of the American culture.
The rate of longitudinal decline (decrease in testosterone concentration in an individual over time) was 1.6 percent, whereas the cross-sectional difference between the two groups (younger men having higher testosterone concentrations than their elders in blood drawn at the same time) was 0.4 percent.1 This means that something associated with the way younger generations are aging is causing testosterone concentrations to decline at a rate four times faster than expected! Even more staggering is the revelation that the age-matched difference is three times as potent as the cross-sectional difference, meaning that something undefined is dropping male testosterone concentrations with an effect three times greater than aging.
Again, these results are representative of results seen in all groups studied— it’s not the result of exaggeration. Consider the magnitude of this difference. The hormonal change experienced in men today from 45 to 54 is the same as the difference between men aged 45 to 81 just 10 years ago. The health impact of low testosterone is only recently being realized due to a systemic bias against research relating to the possible benefits of testosterone. Low testosterone is strongly associated with depression, cardiovascular disease, muscle and bone loss, erectile dysfunction and many other disorders, including early death.2-7
The researchers wisely looked at identified causes of low testosterone to see if excluding these factors could correct the dramatic age-matched decline.1 Many factors were analyzed, including: chronic illness, general health, medications, smoking, BMI (body mass index), employment and marital status. Of these, only increased obesity, increased polypharmacy (using multiple prescription drugs) and decreased smoking affected the results.8-11 Dramatically, these three factors (obesity, prescription drugs and smoking cessation) substantially affected the cross-sectional and longitudinal declines; the age-matched decline only demonstrated a slight correction. After correction, the degree of difference between the cross-sectional and age-matched declines was even more remarkable. The age-matched decline (the reduction in testosterone concentration seen between men who were 65 in 1987 compared to men who were 65 in 1995) was 10 times greater than the cross-sectional difference. The longitudinal decline (the reduction in testosterone concentration experienced by an individual over the course of time) was 11 times the projected rate!1
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Research and Review 
