Basal growth hormone concentrations in blood and the risk for prostate cancer:: A case-control study

OBJECTIVE. To assess the relationship between basal serum growth hormone (GH) levels and prostate cancer risk. METHODS. We conducted a population-based case-control study; cases included 68 men, aged 45-85 years, diagnosed with incident, primary, histologically confirmed, and clinically apparent (stage B and higher) prostate cancer. Controls included 240 men, frequency matched on age and residential area. Age, race, BMI, waist circumference, history of enlarged prostate, education, and current smoking status, were all considered as possible confounders. RESULTS. We found a statistically significant trend of decreasing prostate cancer risk across increasing GH quintiles, in both crude (OR: 0.31, 95% CI: 0.12-0.83, P for trend 0.01) and adjusted models (OR: 0.35, 95% CI: 0.12-1.05, P for trend 0.03), in the highest compared to the lowest quintile, respectively. CONCLUSIONS. Lower basal levels of GH in serum are associated with increased prostate cancer risk. The inverse association may be explained by the negative feedback loop generated by IGF-1 produced by the tumor on GH secretion. (c) 2005 Wiley-Liss, Inc.