The study aims to discover if the sleeping habits of obese children make them more susceptible to learning difficulties, behavioural problems and physiological issues such as breathing, heart and metabolic problems.
University of Otago women's and children's health department PhD student Evan Tan said the study had been running for nearly two years but, so far, he had only been able to attract 18 participants.
More than 30 10- to 18-year-olds were needed to make the study statistically sound.
"Obesity itself is a sensitive topic for both children and parents. There is often a stigma or stereotyping attached.
"For children, they are often afraid of being perceived as lazy, slow and [having a] lack [of] self-control. For parents, they are often afraid of being perceived as negligent.
"Teens are an even more sensitive group. Due to their develop-mental stage - puberty - they are more self-conscious, seeking acceptance and discover-ing their sexuality."
However, Mr Tan said obesity was not something to be ashamed of, because it was a condition that could be fixed.
"Genetics plays a part. It's not always about consciously choosing the wrong choices. Some people may be predisposed due to their genetics.
"Obesity can be controlled and managed, and an ideal body mass index can be achieved - being obese is not terminal."
Mr Tan said many overweight child-ren suffered from a sleep disorder called obstructive sleep apnoea (OSA) - a condition where airways be-come restricted or completely blocked.
It disturbs sleep, which has a negative impact on the child's daytime functioning, he said.
"People who suffer from OSA often feel tired during the day and have trouble concentrating and remembering things. Some don't even realise that they have OSA."
Many studies had been done on OSA in adults, but there was little research about how it affected children and adolescents, he said.
"That's why this study is so important.
"If we can't get enough participants, we will definitely try to extract as many results and as much information as we possibly can, but we will not be able to disseminate our results with as much confidence as we would like to."
Mr Tan said those who participated would be anonymous because their personal information was confidential and coded.
People interested in participating can contact Mr Tan on evan.tan@otago.ac.nz or 470-3881.