A new report from Perth's Telethon Institute for Child Health Research has found a strong link between childhood ear infections and exposure to tobacco smoke.

The families of 100 Aboriginal children and 180 non-Aboriginal children participated in the Kalgoorlie Otitis Media Research Project, allowing the collection of social, demographic, environmental and biological data to investigate the causes of otitis media (middle ear infections). The children had regular ear examinations from birth until 2 years of age.

Chief Investigator Dr Deborah Lehmann, who heads the Institute's infectious diseases research, said ear infections were the most common reason that young children see a doctor and can cause life-long problems.

"Up to 20 per cent of children have more than three ear infections between 1 and 2 years of age. If their hearing is damaged, it can seriously affect their educational outcomes and social circumstances in adulthood," Dr Lehmann said.

"In Aboriginal children, these ear infections typically start at a younger age, are much more common and more likely to result in hearing loss."

Key findings from the project include:

Otitis media was diagnosed at least once in 74% of Aboriginal children and 45% of non-Aboriginal children.

64% of Aboriginal children and 40% of non-Aboriginal children were exposed to environmental tobacco smoke.

If we eliminated exposure to tobacco smoke we estimate that we could reduce ear infections by 27% in Aboriginal children and 16% in non-Aboriginal children

The impact of passive smoking in the home on ear infections was reduced if the children also attended day care.

Dr Lehmann said there is evidence that passive smoking can increase the adherence of bacteria in the respiratory passages and depress the immune system.

"These results highlight the importance of reducing children's exposure to passive smoking, and this is particularly important for Aboriginal people where the rates of both smoking and otitis media are high," she said.

"Few Aboriginal children have access to formal childcare despite studies showing that it is an effective way to improve early development and educational outcomes for disadvantaged children. The fact that it could also reduce the burden of ear infections in Aboriginal children adds weight to calls for appropriate childcare facilities to be provided."

The results are published in the latest edition of the Medical Journal of Australia.