| Objective:Testosterone is essential for the regulation of erectile physiology, but the relationship between low testosterone and erectile dysfunction (ED) has not been firmly established. To examine the association between serum total, free and bio-available testosterone and ED in a population-based sample.Methods:A consecutive series of 1776 men aged 20-77 participated in the routine physical examination from September 2009 to December 2009 in Guangxi, China. ED was assessed using the five-item International Index of Erectile Function (IIEF-5) questionnaire. Total testosterone (TT), sex hormone binding globulin (SHBG) and other biochemical profiles were measured. Free testosterone (FT) and bio-available testosterone (BT) were calculated based on Vermeulen’s formula. Data were collected with regard to smoking, alcoholic drinking, physical activity and metabolic syndrome.Results:The prevalence of ED (IIEF-5<22) was 47.6%. Men with ED were significantly older, and more prone to smoke cigarettes (≥20 cigarettes/day) or drink alcoholic (≥3 drinks/week), and more likely to have elevated blood pressure (P=0.036) or hyperglycemia (P<0.001) compared with those without ED. The significant increase in SHBG with age was parallel to its increase with increasing severity of ED (P<0.001). The obscure increase in TT across the ED status was detected without significance (P=0.418), but TT was positively associated with ED after adjustment for age [odds ratio (OR)=1.02,95% CI (confidence internal): 1.00-1.04]. FT and BT were inversely associated with ED (OR=0.14, 95%CI:0.06-0.33; OR=0.92 (95%CI:0.89-0.96, respectively) in the univariate analysis, and this inverse association appeared to be independent of smoking status, alcoholic drinking, physical activity, hyper-triglyceridemia and hyperglycemia.Conclusions:FT and BT are inversely related to worsening ED, whereas the positive association between TT and ED is most likely due to the increase in SHBG.Objective:The decline of testosterone has been known to be associated with the prevalence of erectile dysfunction (ED), but the causal relationship between sex hormones and ED is still uncertain. To prove the association between sex hormones and ED, we carried out a prospective cohort study based on our previous cross-sectional study.Methods:We performed a prospective cohort study of 733 Chinese men who participated in Fangchenggang Area Males Health and Examination Survey from September 2009 to December 2009 and were followed for 4 years. Erectile function was estimated by scores of the five-item International Index of Erectile Dysfunction (IIEF-5) and relative ratios (RRs) were estimated using the Cox proportional hazards regression model. Data was collected at follow-up visit included sex hormone measurements, IIEF-5 scores, physical examination and health questionnaires.Results:Men with the highest tertile of FT (RR=0.21,95%CI:0.09-0.46) and the lowest tertile of SHBG (RR=0.38,95%CI:0.19-0.73) had decreased risk of ED. In young men (aged 21-40), a decreased risk was observed with the increase of FT and BT [adjusted RR and 95%CI:0.78 (0.67-0.92) and 0.75 (0.62-0.95), respectively]. TT (RR=0.89,95%CI: 0.81-0.98) was inversely associated with ED after adjusting for SHBG, while SHBG (RR=1.04,95%CI:1.02-1.06) remained positively associated with ED after further adjusting for TT. Men with both low FT and high SHBG had highest ED risk (adjusted RR=4.61,95%CI: 1.33-16.0).Conclusions:High FT and BT levels independently predicted a decreased risk of ED in young men. Further studies are urgently needed to clarify the molecular mechanisms of testosterone acting on ED.Objective:Osteocalcin can regulate energy metabolism and increase testosterone production. Although previous studies has showed the positive association between osteocalcin and testosterone, the effect of metabolic factors in the association is unclear.Methods:Osteocalcin, testosterone, and metabolic factors were accessed in 2400 men aged 20 to 69 years, who participated in the population-based Fangchenggang Area Male Health and Examination Survey in Guangxi province of China from September 2009 to December 2009. Metabolic syndrome (MetS) was defined based upon the updated report of National Cholesterol Education Program Adult Treatment Panel III (NCEP ATPIII criteria). Serum total osteocalcin, total testosterone (TT) and sex hormone binding globulin (SHBG) were measured, while free testosterone (FT) and bioavailable testosterone (BT) were calculated based on Vermeulen’s formula. The multivariable linear regression analysis was used.Results:Osteocalcin was positively associated with TT, FT and BT in the unadjusted model (all P<0.001). After adjusting for age, the positive association between osteocalcin and TT remained statistically significant (β=0.17,95%CI=0.14-0.20), and was not attenuated in each MetS subgroup including hypertriglyceridemia, hyperglycemia, elevated BP and low HDL-c, while in the group of central obesity (waist circumstance>90cm), the association appeared significantly stronger (0=0.21,95%CI=0.12-0.30). After further adjusting for SHBG, osteocalcin was positively associated with TT, FT and BT in men with central obesity or men with any two of MetS components (all P<0.05).Conclusions:Serum total osteocalcin is positively associated with testosterone, which is probably modified by SHBG and central obesity.Objective:The osteocalcin has been known to be associated with the prevalence of metabolic syndrome, which is a main risk factor for erectile dysfunction (ED). To prove the association between osteocalcin and ED, we carried out a prospective cohort study based on our previous cross-sectional study.Methods:We performed a prospective cohort study of 757 Chinese men who participated in Fangchenggang Area Males Health and Examination Survey from September 2009 to December 2009 and were followed for 2 years. Erectile function was estimated by scores of the five-item International Index of Erectile Dysfunction (IIEF-5) and relative ratios (RRs) were estimated using the Cox proportional hazards regression model. Data was collected at follow-up visit included sex hormone measurements, IIEF-5 scores, physical examination and health questionnaires.Results:Men with new diagnosed ED had a lower level of serum osteocalcin than men without ED within two years. Men with the highest tertile of glucose had an increased risk of ED (RR=1.94,95%CI: 1.44-2.61). In men with hyperglycemia (glucose>=5.6mmol/L), an increased risk of ED was observed in men with high level of serum osteocalcin (adjusted RR=2.65,95%CI:1.74-4.02). Compared with men with low level of glucose and high level of osteocalcin, men with high level of glucose and high level of osteocalcin had an increased risk of ED (adjusted RR=2.31,95%CI:1.57-3.42), even when those men with mild ED was removed (adjusted RR=2.73,95%CI:1.16-6.43).Conclusions:High osteocalcin and glucose levels independently predicted a increased risk of ED in men from general population. Further studies are urgently needed to clarify the molecular mechanisms of osteocalcin acting on ED. |
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