Objectives To study the association between cigarette smoking and sperm density in men of reproductive age. Methods We enrolled 224 male employees of a modern petrochemical plant in Nanjing, China. These men had no pr...Objectives To study the association between cigarette smoking and sperm density in men of reproductive age. Methods We enrolled 224 male employees of a modern petrochemical plant in Nanjing, China. These men had no prior history of infertility or other reproductive diseases. Epidemiologic data, including information on smoking and other occupational and lifestyle exposures were obtained by a questionnaire interview. Semen specimens were collected from each participant and analyzed according to the WHO guidelines. Regression analyses were performed to estimate the effect of smoking on sperm density. Results Approximately 67% of the subjects had ever smoked cigarettes. Different measurements of smoking behavior were each associated with decreased sperm density. There was a significant dose-response trend between the tertites of total smoking amount in pack-years and sperm density. As compared to men who never smoked, current smokers had a significant reduction in sperm density (-13.3×106/ml; 95% CI, - 24. 1, -2. 5) ,while ex-smokers had only a small decrement in sperm density ( -2. 6×106/ml; 95%CI, -18. 7,13. 5). Starting smoking at less than 20 years of age was associated with significant reduction in sperm density (- 14.8×106/ml; 95% CI, - 27. 4, -2. 2). Starting smoking at 20 years or older was associated with a slightly smaller decrease ( -10.1×106/ml; 95% CI,-21.7,1.4). Conclusions Cigarette smoking is associated with decreased sperm density, showing an evident dose-response trend in this population.展开更多
文摘Objectives To study the association between cigarette smoking and sperm density in men of reproductive age. Methods We enrolled 224 male employees of a modern petrochemical plant in Nanjing, China. These men had no prior history of infertility or other reproductive diseases. Epidemiologic data, including information on smoking and other occupational and lifestyle exposures were obtained by a questionnaire interview. Semen specimens were collected from each participant and analyzed according to the WHO guidelines. Regression analyses were performed to estimate the effect of smoking on sperm density. Results Approximately 67% of the subjects had ever smoked cigarettes. Different measurements of smoking behavior were each associated with decreased sperm density. There was a significant dose-response trend between the tertites of total smoking amount in pack-years and sperm density. As compared to men who never smoked, current smokers had a significant reduction in sperm density (-13.3×106/ml; 95% CI, - 24. 1, -2. 5) ,while ex-smokers had only a small decrement in sperm density ( -2. 6×106/ml; 95%CI, -18. 7,13. 5). Starting smoking at less than 20 years of age was associated with significant reduction in sperm density (- 14.8×106/ml; 95% CI, - 27. 4, -2. 2). Starting smoking at 20 years or older was associated with a slightly smaller decrease ( -10.1×106/ml; 95% CI,-21.7,1.4). Conclusions Cigarette smoking is associated with decreased sperm density, showing an evident dose-response trend in this population.
