Researchers from the University of Melbourne have been able to track childhood risk factors in developing obstructive sleep apnea later in life, in the first longitudinal study of its kind.

The study, published in Respirology, shows some childhood exposures, such as parental smoking and respiratory tract infections as a child are risk factors for obstructive sleep apnea in middle-aged adults.

Obstructive sleep apnea is a common sleep-related breathing disorder that occurs when the muscles in the throat relax during sleep, partially or fully blocking the airway.

Symptoms include loud snoring and noisy breathing, and it can impact overall sleep quality and health, and often leaves sufferers feeling fatigued.

The study used data from 3,550 people drawn from the population-based Tasmanian Longitudinal Health Study (TAHS), dating back to 1968. A longitudinal study is a research method that involves collecting data from the same group of individuals or subjects over an extended period to track changes and relationships over time.

At age 7, participants' parents completed a survey on their behalf, and participants were followed up between the ages of 51 and 54.

The study found several childhood risk factors including maternal asthma and smoking, parents' smoking habits, as well as childhood pneumonia, asthma and bronchitis that were associated with probable obstructive sleep apnea.

Research Fellow Chamara Senaratna from the Allergy and Lung Health Unit in the Melbourne School of Population and Global Health at the University of Melbourne, said the study provides the first known evidence of childhood risk factors for developing the disorder.

"This study should stimulate further research into this area, including flagging the future risk of developing obstructive sleep apnea," Dr. Senaratna said.

"It may be useful in a clinical setting to create awareness and vigilance in at-risk groups."

It is estimated 1 billion adults worldwide suffer from obstructive sleep apnea, although it remains under-diagnosed.

Dr. Senaratna said there are many known risk factors for developing the condition, including obesity, older age and carrying weight around the middle of the body. Males are also more likely to develop the condition.

Study senior author, head of the Allergy and Lung Health Unit Professor Shyamali Dharmage, said undiagnosed obstructive sleep apnea has links to chronic cardiovascular disease, stroke, diabetes, depression, chronic obstructive pulmonary disease, asthma and cancer.

"We view this study as a stepping stone for further research into this field," Professor Dharmage said.

The TAHS is a longitudinal study that spans across six decades with its participants investigated every decade.