Shift work ranked just below asbestos in the list of agents associated with work-related cancer deaths in the U.K. Now, American Medical Association (AMA) has acknowledged that nighttime lighting could lead to serious health issues.

We often hear about air and water pollution and to some extent noise pollution. But, there is a thing called light pollution as well. It's when you can't sleep at night because of the streetlights, traffic lights or light from TV or a computer.

Millions of workers work in rotational shifts. Staying awake at times when the body wants to sleep disturbs the rhythm of the body. This changed sleeping pattern can cause stress, anxiety and weight gain and although rare, it can even cause cancer.

"It is recognition by a major health body, the American Medical Association, that this is an emerging environmental issue that has a potentially large impact on the health of society. Based on an accumulation of evidence, this august body is now making the statement: 'We take this seriously, and the public should take it seriously too,'" said Richard Stevens, cancer epidemiologist and professor in the UConn School of Medicine Department of Community Medicine and Health Care.

According to 'The first World Atlas of the artificial night sky brightness', "about two-thirds of the World population and 99 per cent of the population in the United States (excluding Alaska and Hawaii) and European Union live in areas where the night sky is above the threshold set for polluted status".

Richard Stevens has studied artificial light and its effects for almost 25 years.

"There’s no question that this light at night changes our physiology in the short term. We know that artificial light disrupts circadian rhythms. We’re learning more and more about the specifics of what that means. The clearest evidence is about the hormone melatonin. We’re lowering it, we’re even suppressing it completely, depending on the amount of light," Stevens said.

However there is still no conclusive evidence that says artificial light causes cancers. Experts believe more studies will be required before nightlight can be tied to cancers.