Table 3: Association between prostate cancer grade and sexual behaviors.

Multivariate-adjusted OR (95% CI)
Low-grade PC
OR (95% CI)
High-grade PC
OR (95% CI)
All PC cases
OR (95% CI)

Age at first sexual intercourse (years)a
 <161.63 (1.03, 2.60)*1.82 (1.11, 2.99)*1.74 (1.20, 2.54)*
 16–181.28 (0.82, 2.00)1.66 (1.04, 2.66)*1.43 (1.00, 2.05)*
 19–211.25 (0.84, 2.18)1.50 (0.90, 2.49)1.36 (0.92, 2.00)
 >211.0 (reference)1.0 (reference)1.0 (reference)
-trend = 0.06 -trend = 0.02 -trend = 0.004

Lifetime no. of sexual partnersb
 0–31.0 (reference)1.0 (reference)1.0 (reference)
 4–91.04 (0.74, 1.46)1.05 (0.74, 1.48)1.00 (0.76, 1.31)
 10–201.21 (0.82, 1.78)1.16 (0.78, 1.73)1.14 (0.83, 1.56)
 >201.09 (0.64, 1.87)1.74 (1.06, 2.85)*1.35 (0.89, 2.04)
-trend = 0.65 -trend = 0.02 -trend = 0.10

Sexually transmitted infectionc1.00 (0.76, 1.31)1.01 (0.77, 1.33)1.01 (0.82, 1.26)

OR: odds ratio; CI: confidence interval.
* , based on logistic regression analyses adjusted for age, marital status, religion, lifetime occupation, family history of PC, and waist-hip ratio.
aSample size for low-grade PC: 412; high-grade PC: 373; all PC cases: 825; controls: 808.
bSample size for low-grade PC: 349; high-grade PC: 327; all PC cases: 707; controls: 708.
cSample size for low-grade PC: 476; high-grade PC: 426; all PC cases: 948; controls: 930.