Plain language summary
Studies have shown that people with diabetes mellitus have lower risk of developing prostate cancer compared with non-diabetics. Glucose metabolism (the process by which simple sugars found in food are processed and used to produce energy) may have an independent role in prostate cancer development and progression. The aim of this study was to investigate the associations between fasting blood glucose and glycaemic control and prostate cancer risk. The study recruited 80,144 men who were randomly assigned either to be screened with PSA at four-year intervals (the screening arm, 31,866 men) or to control arm with no intervention and followed through national registries (48,278 men). Results indicate an association between fasting blood glucose level and elevated prostate cancer risk. This association was more noticeable in the screening arm, and concerned both poorly and well-differentiated cancers. Furthermore, compared to the normoglycemic men, overall prostate cancer risk was elevated in diabetic, but not in pre-diabetic men. Authors conclude that diabetic fasting blood glucose level is associated with elevated prostate cancer risk in a population-based cohort of Finnish men.
Abstract
BACKGROUND Diabetic men have lowered overall risk of prostate cancer (PCa), but the role of hyperglycaemia is unclear. In this cohort study, we estimated PCa risk among men with diabetic fasting blood glucose level. METHODS Participants of the Finnish Randomized Study of Screening for Prostate Cancer (FinRSPC) were linked to laboratory database for information on glucose measurements since 1978. The data were available for 17,860 men. Based on the average yearly level, the men were categorised as normoglycaemic, prediabetic, or diabetic. Median follow-up was 14.7 years. Multivariable-adjusted Cox regression was used to calculate hazard ratios (HRs) and 95% confidence intervals (95% CIs) for prostate cancer overall and separately by Gleason grade and metastatic stage. RESULTS In total 1,663 PCa cases were diagnosed. Compared to normoglycaemic men, those men with diabetic blood glucose level had increased risk of PCa (HR 1.52; 95% CI 1.31-1.75). The risk increase was observed for all tumour grades, and persisted for a decade afterwards. Antidiabetic drug use removed the risk association. Limitations include absence of information on lifestyle factors and limited information on BMI. CONCLUSIONS Untreated diabetic fasting blood glucose level may be a prostate cancer risk factor.
Methodological quality
Jadad score
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2
Allocation concealment
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Yes
