From an article on the study:
Risk was estimated using multivariable-adjusted Cox regression in 199,698 male UK Biobank participants. 2-sample Mendelian randomization (MR) analysis of IGF-I and risk used genetic instruments identified from UK Biobank men and genetic outcome data from the PRACTICAL consortium (79,148 cases and 61,106 controls). 5,402 men were diagnosed with and 295 died from prostate cancer (mean follow-up 6.9 years). Higher circulating IGF-I was associated with elevated prostate cancer diagnosis (HR per 5 nmol/L increment=1.09, 95% CI 1.05-1.12) and mortality (HR per 5 nmol/L increment=1.15,1.02-1.29). MR analyses also supported the role of IGF-I in prostate cancer diagnosis (cis-MR odds ratio per 5 nmol/L increment=1.34,1.07-1.68). In observational analyses, higher free testosterone was associated with a higher risk of prostate cancer (HR per 50 pmol/L increment=1.10,1.05-1.15). Higher SHBG was associated with a lower risk (HR per 10 nmol/L increment=0.95,0.94-0.97), neither was associated with prostate cancer mortality. Total testosterone was not associated with prostate cancer. These findings implicate IGF-I and free testosterone in prostate cancer development and/or progression.
Risk was estimated using multivariable-adjusted Cox regression in 199,698 male UK Biobank participants. 2-sample Mendelian randomization (MR) analysis of IGF-I and risk used genetic instruments identified from UK Biobank men and genetic outcome data from the PRACTICAL consortium (79,148 cases and 61,106 controls). 5,402 men were diagnosed with and 295 died from prostate cancer (mean follow-up 6.9 years). Higher circulating IGF-I was associated with elevated prostate cancer diagnosis (HR per 5 nmol/L increment=1.09, 95% CI 1.05-1.12) and mortality (HR per 5 nmol/L increment=1.15,1.02-1.29). MR analyses also supported the role of IGF-I in prostate cancer diagnosis (cis-MR odds ratio per 5 nmol/L increment=1.34,1.07-1.68). In observational analyses, higher free testosterone was associated with a higher risk of prostate cancer (HR per 50 pmol/L increment=1.10,1.05-1.15). Higher SHBG was associated with a lower risk (HR per 10 nmol/L increment=0.95,0.94-0.97), neither was associated with prostate cancer mortality. Total testosterone was not associated with prostate cancer. These findings implicate IGF-I and free testosterone in prostate cancer development and/or progression.
