Study of environmental risk factor in semen quality of male

• Main Authors: Ching-Jen Li, 李清仁
• Other Authors: Ling-Chu Chien
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/6z82y9

博士 === 臺北醫學大學 === 公共衛生學系暨研究所 === 104 === Semen quality is a key indicator of the male reproductive ability. The decline in semen quality has been debated for several decades. However, this decline might be inconsistent given factors such as geographical area, ethnicity, environmental exposure, and lifestyle changes. Taiwan is an urbanized and industrialized island, where pollution is a pressing problem. In addition, lifestyle-related factors, such as dietary patterns and obesity, have changed tremendously in recent years. This study aimed to provide information on the semen quality of Taiwanese men by analyzing semen parameters between 2001 and 2010. In addition, we evaluate the levels of heavy metals and reproductive hormones in the blood to clarify the relationship between these factors and semen quality or subfertilty. Objective: 1. To understand the status and trends of semen quality from 2000 to 2010 in North Taiwan men. 2. To understand the relationship between lead and low semen quality. 3. To understand the relationship among metal, semen parameters, and fertility, and determine the values of suitable sperm parameters for Taiwanese men. Method: We recruited 7187 male participants between 2001 and 2010 from a reproductive medical center to provide information on the semen quality of Taiwanese men. In cross-sectional study, we collected demography information and measured the levels of metals and reproductive hormones in the blood. To determine the association between blood lead levels and low semen quality. In case-control study, we examined the blood lead (Pb) levels and semen quality in the fertile and subfertile men. In addition, receiver operating characteristic (ROC) curve analysis was used to determine the cutoff values of suitable sperm parameters for Taiwanese men to achieve spontaneous pregnancy. Result: Increasing age (per year) was significantly and negatively associated with semen volume, progressive sperm motility, rapid progressive sperm motility, and sperm with normal morphology. In addition, all semen parameters were reduced with year by year of recruitment. We observed that the increased blood Pb levels were significantly and positively associated with low semen quality. High blood Pb levels ( 5 g/dL) had an 11-fold risk of low semen quality. Our data also suggest that low percentages of total and progressively motile sperms were significant risk factors for subfertility. In addition, the percentage of sperms with normal morphology had a higher ROC curve area (0.87), and the new cutoff point for the percentage of sperms with normal morphology was determined to be 65% and those having <65% of sperms with normal morphology had an 11.35-fold higher risk of subfertility. Disscision and Conclusion: In this study, age and cohort effect on reduced the progressive and rapid progressive sperm motility. Even blood Pb levels lower than the reference level of the CDC and FSH levels were within the normal recommended range, we observed that the increased blood Pb levels were significantly and positively associated with low semen quality. In addition, low percentages of total and progressively motile sperms were significant risk factors for subfertility. Moreover, the new cutoff point for the percentage of sperms with normal morphology (65%) should be determinated with larger sample size in future. This information will be of use in clinical practice and public health investigations of the male reproductive health.