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People in their 30s waking up with a dry mouth should not necessarily blame it on too much alcohol from the night before.

A recent study has shown that 10 per cent of Kiwis in their 30s suffer from a condition known as "chronic dry mouth" - normally associated with older people.

University of Otago School of Dentistry's Professor Murray Thomson, an authority on the condition, which is clinically known as xerostomia, said previous study had focused on the effect it had on older people.

"What we have found is that xerostomia is experienced by a much younger age group and affects their oral health, as well as their day-to-day lives," he said.

"They show higher rates of tooth decay, tooth loss and periodontal disease. They also report higher incidence of physical pain and functional limitations."

The research was published in the online journal Health and Quality of Life Outcomes earlier this month.

Professor Thomson found that xerostomia was higher among those taking antidepressants, iron supplements or narcotic analgesics such as codeine.