Thanks for sharing this paper. Taking it at face value besides the great nice observations from @blshaw
Analysis sample
To enhance comparability of age distributions across study waves and to allow for analyses of T concentrations by subjects’ birth cohorts, data were restricted to observations obtained on men of age 45–79 yr born between 1916 and 1945, inclusive. This yielded potential samples of 1399, 975, and 579 observations at T1, T2, and T3, respectively. Of these, we excluded all observations on the seven men who had T1 serum total T less than 100 ng/dl (3.5 nmol/liter), and two outlying observations with total T more than 1200 ng/dl (41.6 nmol/liter). One hundred twenty-six observations were excluded because they were taken on subjects who, before the relevant study wave, had a diagnosis of prostate cancer, for which treatment via hormone suppression therapy could not be ruled out. An additional 44 observations were excluded because subjects lacked complete health data. This yielded samples of 1374, 906, and 489 observations at T1, T2, and T3, respectively, totaling 2769 observations taken on 1532 men.
Notice the max range of the y-axis:
I was trying to be generous with setting upper bound at 1200 ng/dL up above. Pretty consistent range across studies.