Table IV.

Semen variables for the men in cohort B at different ages.

Age (years)	19	21	25	29	P-value
n	197	110	96	90
Semen volume (ml)	3.4 (3.5) 0.6–9.0	3.5 (3.6) 0.4–10.9	3.7 (3.9) 1.0–8.9	3.5(3.8) 0.8–8.9	0.51 19y versus 21y 0.09 19y versus 25y 0.59 19y versus 29y 0.79 21y versus 25y 1.00 21y versus 29y 0.96 25y versus 29y
Sperm concentration (million/ml)	50 (63) 0–274	57 (63) 0–263	46 (57) 0–195	62 (71) 0–171	0.96 19y versus 21y 0.43 19y versus 25y 0.09 19y versus 29y 0.76 21y versus 25y 0.03 21y versus 29y 0.007 25y versus 29y
Total sperm count (million)	172 (199) 0–785	171 (209) 0–975	168 (217) 0–1361.7	225 (264) 0–1077	1.00 19y versus 21y 1.00 19y versus 25y 0.009 19y versus 29y 0.02 21y versus 29y 1.00 21y versus 25y 0.02 25y versus 29y
Motility (abc, %)	76 (73) 18–91	79 (76) 21–93	82 (77) 21–94	81 (76) 18–96	0.02 19y versus 21y 0.002 19y versus 25y 0.03 19y versus 29y 0.85 21y versus 25y 0.90 21y versus 29y 1.00 25y versus 29y
Total motile count (million)	130 (148) 0–573	132 (162) 0–711	138 (174) 0–1034	183 (210) 0–717	0.88 19y versus 21y 0.73 19y versus 25y <0.001 19y versus 29y 0.99 21y versus 25y 0.01 21y versus 29y 0.02 25y versus 29y

P-value <0.05 is considered significant, shown in bold. Results are shown as median (mean) and range. Mixed model of repeated measures analyses following a square root transformation was used. P-values for pairwise comparisons were adjusted using the Tukey–Kramer methods. For other adjustments see statistical methods.