Chemical exposure a suspected contributor to significant drop in sperm count worldwide over last 40 years

[The New York Times] In a worldwide meta-analysis of 185 studies, an international team of researchers examined studies that assessed semen samples data from 42,935 men in 50 countries between 1973 and 2011 to better understand trends in reproductive health. Based on data in these 185 studies, they calculated sperm concentration (the number of sperm per milliliter of semen) has declined 52.4 percent, while total sperm count declined 59.3 percent over the nearly 40 year period. Interestingly, non-Western men included in the study were not found to have a decline in sperm quality. The first study of its kind, these results point toward a troubling trend that merits further attention and analysis to more fully understand the underlying causes behind declining sperm health.

While there are no clear conclusions regarding direct causes, the authors highlight previous research which has pointed toward lifestyle and environmental factors such as exposure to alcohol, cigarette smoke, and chemicals while in utero, as well as stress, obesity, and age as potential contributors to the drop. Prenatal exposure to phthalates and other endocrine disrupting chemicals (EDCs) have been shown to affect the development of males, disturbing normal male hormone function and male genital development. Given researchers only started to measure and examine levels of EDCs in urine about twenty years ago, there is a gap in information about the historical levels of chemicals in humans, which could otherwise contribute to a more complete understanding of the situation.

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