Endocrine disruptors culprits in declining sperm quality
Endocrine disruptors, which can be found in plastics, pesticides and receipts from thermal printers, have been linked to declining sperm quality in adults, says an expert.
Speaking in an interview with MIMS Doctor, Professor Dr. Mustafa Ali Mohd of the Faculty of Medicine, University of Malaya, said scientists have observed a steady decline in sperm quality since as early as the 1990s and the drop in sperm quality was associated with exposure to endocrine disrupting chemicals (EDCs). Around the year 2000, scientists discovered plastics contained EDCs that were contributors of endocrine related conditions such as reduced sperm quality, obesity and diabetes.
Endocrine disruptors affect some receptors of the endocrine system by making it unresponsive, act negatively or give unexpected effects, explained Mustafa. Plastics contain an EDC known as phthalates, which is the most abundantly produced plasticizer—a substance, typically a solvent added to a synthetic resin to produce or promote plasticity—and has been associated with testicular dysgenesis syndrome. [Trends Endocrinol Metab 2009;20(3):139–145] Moreover, a recent study showed that phthalate exposure in early pregnancy is associated with a higher prevalence of male genital abnormalities in the newborns. [J Clin Endocrinol Metab 2017. Doi: 10.1210/jc.2016-3837]
There are various local studies available on the exposure to EDC. Among the findings was the presence of many types of EDC in drinking water and high levels of various EDCs in the river water in certain parts of the country, said Mustafa. [J Water Health 2013;11(2):311–323, Clean Soil Air Water 2015;43:804–810] Malaysians are frequently exposed to EDCs from domestic plastic materials such as plates, cups, containers and cooking wares. Worryingly, EDCs have been detected in breast milk and cord blood of newborns as well, said Mustafa.
The quality of sperm is on the decline, with reported reduction in semen volume, sperm concentration, sperm forward motility and total sperm count. At the same time, the incidence of reproductive disorders such as testicular cancer is on the rise. [BMJ 1992;305(6854):609–613, Asian J Androl 2016. Doi:10.4103/1008-682X.179533, Reprod Med Biol 2007;6:185]
At the moment, the exact cause and mechanism behind the declining trend in sperm quality is still being studied. Regardless of the cause of the decline, sperm quality is a vital factor in determining fertility and it will be wise to avoid materials that contain endocrine disruptors, advised Mustafa.
Endocrine disruptors are chemicals that have adverse effects on the endocrine system, leading to disrupted developmental, neurological, reproductive and immune systems. [National Institute of Environmental Health Sciences. Available at: https://www.niehs.nih.gov/health/topics/agents/endocrine/. Last accessed 3rd April]