Different effect of obesity and metabolic syndrome on prostate cancer by age group.

Substantial evidence supports that metabolic syndrome (MetS) affects the incidence of several cancers, with different effects according to age group. We hypothesized that MetS has an age-specific effect on the occurrence of prostate cancer. We studied a National Health Insurance Service health checkup cohort. A total of 5,370,614 men in the cohort were categorized into three age groups in 2009 (20-39, 40-64, ≥65). Prostate cancer incidence was estimated on a cumulative basis from 2009 to 2018. We tried to identify the correlation of MetS components and prostate cancer by age group using this large retrospective cohort. MetS components included the body mass index (BMI), waist circumference (WC), hypertension, obesity, hyperlipidemia, cardiovascular disease, smoking, drinking, serum glucose, serum total cholesterol, serum triglyceride, serum high-density lipoprotein (HDL)-cholesterol and serum low-density lipoprotein (LDL)-cholesterol. A multivariate Cox proportional hazard model was used for the incidence of prostate cancer according to the MetS component. In the young age (20-39) group, the MetS component was not related to prostate cancer. In the middle-aged (40-64) group, the presence of MetS, WC, HDL cholesterol, and hypertension was significantly associated with an increased prevalence of prostate cancer. In the old age (≥65) group, the presence of MetS, WC, HDL cholesterol, triglycerides, and hypertension were significant factors for the incidence of prostate cancer. This tendency was marked in BMI>30 in the old age group (odds ratio: 1.32;