Circulating Insulin-Like Growth Factor-I and Binding Protein-3 and Risk of Prostate Cancer

NOTE: A tumor was classified as aggressive if Gleason score was >7 or stage was advanced (T₄ or N+ or M+). We were not able to define aggressiveness for six cases because Gleason score and tumor stage were not available (clinical diagnoses only).

↵* Quartiles were assigned within each laboratory batch to adjust for any variation between batches.

↵† HRs from Cox regression models adjusted for country of birth (Australia/New Zealand, United Kingdom, Italy, or Greece) and alcohol consumption. The Prentice method has been used to take into account the case-cohort sampling (see Materials and Methods). HRs by tumor aggressiveness and age at diagnosis were obtained from Cox regression models fitted using competing risks methods.

↵‡ The hypothesis of a linear trend in the HR was tested, including in the model a pseudo-continuous variable computed assigning the median level of the specific hormone for each quartile.

↵§ Test for difference in the estimates for the pseudo-continuous variables (i.e., linear trend) between aggressive and nonaggressive cases and between early-onset and late-onset cases.

↵∥ Test for difference in the estimates for the pseudo-continuous variables (i.e., linear trend) between the first 2 years and the rest of the follow-up.