Noisy streets may up male infertility: study

Prolonged exposure to noises of a busy street or even an air conditioner - particularly at night - may up infertility in men, a study warns.
The scientists, from Seoul National University in the Republic of Korea, say it is important to consider noise when assessing environmental conditions that contribute to infertility.
They found that exposure above the WHO night noise level (55 dB - equivalent to the noise of a suburban street) is linked to a significant increase in infertility.
Noise has been linked to health problems, such as heart disease and mental illness, and has been shown to change social behaviour and interfere with the performance of complex tasks.

Previous research focused on fertility in women has shown a link between exposure to noise and birth-related problems, such as premature birth, spontaneous abortion and congenital malformations.
The new study reveals that long-term exposure to relatively low levels of noise, particularly at night, may contribute to the development of infertility in men.

"Infertility is becoming a significant public health issue because of unexpected adverse effects on the health and quality of life and heavy expenditures on the health system," said Jin-Young Min, from Seoul National University.
"We know noise exposure has an effect on male fertility in animals, but our study is the first to show the risk of exposure to environmental noise on male infertility in humans," said Min.

Worldwide infertility problems affect one in six couples at least once in their lifetime, either temporarily or permanently.
This may be down to a variety of causes, such as genetic abnormalities, infectious disease, environmental agents or certain behaviours.
Min wanted to find out whether environmental exposure to noise, for example at work, has an impact on male infertility.
The researchers analysed a health insurance dataset, focusing on 206,492 men aged 20-59.
They calculated the levels of noise exposure using information from the National Noise Information System combined with the men's postal codes.
In the eight years covered by the study (2006-2013), 3,293 had an infertility diagnosis.

After adjusting the data for variables like age, income, BMI and smoking, they found the chances of being diagnosed infertile were significantly higher in men exposed to noise over 55 dB at night - about as noisy as a suburban street or an air conditioner.