Childhood obesity disrupts the timing of puberty and may affect fertility in later life, suggests a new study.

Oregon State University scientists have found that obesity among young girls can cause early puberty and it affects liver, pancreas, endocrine glands which ultimately lead to complications to reproductive system.

"The issue of so many humans being obese is very recent in evolutionary terms, and since nutritional status is important to reproduction, metabolic syndromes caused by obesity may profoundly affect reproductive capacity," said Patrick Chappell, assistant professor of veterinary medicine at Oregon State University.

"Either extreme of the spectrum, anorexia or obesity, can be associated with reproduction problems," he said.

The research shows childhood obesity affects the kisspeptin, a neurohormone that is necessary for reproduction. Normal secretions of this hormone may be disrupted by endocrine signals from fat that serve to communicate to the brain. The finding was published in Frontiers in Endocrinology.

Another reason behind early puberty and reproductive abnormalities is the disruption of circadian clocks, a natural day and night cycle. Disrupted sleep-wake cycles can affect the secretion of hormones- such as cortisol, testosterone and insulin- that cause reproductive abnormalities.

"Any disruption of circadian clocks throughout the body can cause a number of problems, and major changes in diet and metabolism can affect these cellular clocks. Disruption of the clock through diet can even feed into a further disruption of normal metabolism, making the damage worse, as well as affecting sleep and reproduction," Chappell said.

Early puberty has a major impact on health and there is an increased risk of reproductive cancers, adult-onset diabetes, and metabolic syndrome associated with it. Studies have also found that early puberty is linked to increased rates of depression and anxiety in girls.

Scientists claim that further studies will help them understand more about the link between childhood obesity and its effects on puberty and reproductive abnormalities.