DIFFERENCES IN THE QUALITY OF SEMEN IN OUTDOOR WORKERS DURING SUMMER AND WINTER
DIFFERENCES IN THE QUALITY OF SEMEN IN OUTDOOR WORKERS DURING SUMMER AND WINTER
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DOI：
10.1056/nejm199007053230103
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发表时间：
1990-07-05
影响因子：
158.5
通讯作者：
WORKING, PK
中科院分区：
文献类型：
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作者：
LEVINE, RJ;MATHEW, RM;WORKING, PK
在世界各地温暖的气候中，春季出生人数不足。为了确定这种缺陷是否可能反映了前一个夏天热对男性生殖能力的有害影响，我们在夏季和冬季从美国德克萨斯州圣安东尼奥附近的户外工作的正常男性中获得精液标本，并使用图像分析系统进行自动精液分析。对131名无精子症男性进行配对比较，他们在夏季和冬季都提供了标本，结果显示夏季精子浓度、每次射精的精子总数和活动精子浓度显著降低。调整潜在混杂特征后，这些值的平均下降分别为32%（95%置信限，28%和44%），24%（95%置信限，18%和43%）和28%（95%置信限，24%和44%）（P < 0.0001）。受试者的平均精子浓度和活动精子浓度越低，减少的幅度越大。然而，我们发现夏季在没有空调的环境中每天工作的小时数与夏季精子浓度或夏季和冬季之间的浓度差异之间没有相关性。在这项研究中，那些妻子在分娩前一年住在圣安东尼奥附近的男性的孩子中，春天出生的比例低得不成比例。精液质量在夏季会下降。这种现象至少可以部分解释气候温暖地区人口出生率下降的原因。
In warm climates throughout the world, there is a deficit of births during the spring season. To determine whether this deficit might reflect a deleterious effect of heat on the male reproductive capacity during the previous summer, we obtained semen specimens in summer and winter from normal men who worked outdoors in the vicinity of San Antonio, Texas (USA), and we performed automated semen analyses with an image-analysis system. Pairwise comparison among 131 men without azoospermia who contributed specimens in both summer and winter revealed significant reductions during the summer in sperm concentration, total sperm count per ejaculate, and concentration of motile sperm. The mean decreases in these values after adjustment for potential confounding characteristics were 32 percent (95 percent confidence limits, 28 and 44 percent), 24 percent (95 percent confidence limits, 18 and 43 percent), and 28 percent (95 percent confidence limits, 24 and 44 percent), respectively (P < 0.0001). The lower a subject''s average sperm concentration and motile-sperm concentration, the greater the reduction. We found no correlation, however, between the number of hours per day spent working during the summer in settings without air conditioning and either the summer sperm concentration or the difference in concentration between summer and winter. Among the children of the men in the study whose wives were living near San Antonio during the year before they gave birth, a disproportionately low number were born during the spring. Semen quality deteriorates during the summer. This phenomenon may account at least in part for the reduction in the birth rate during the spirng in regions with warm climates.