A type of medication widely used by older Australians may increase the risk of Alzheimer’s disease, a new study suggests.

Some kinds of incontinence drugs, anti-Parkinson drugs, sleeping pills and anti-depressants prescribed in Australia are classed as anticholinergics, which the research links to dementia.

The large study was published by JAMA Internal Medicine, a highly-regarded peer-reviewed journal based in the US.

• Tax soft drinks not carrots, urge health groups
• How to protect your money from divorce
• Coles pleads guilty to lightweight steaks

The researchers tracked nearly 3,500 men and women aged 65 and over for seven years, and found that 800 had developed dementia. Those who took higher doses of the anticholinergic drugs (which block a neurotransmitter in the brain and body) were more likely to develop the illness, even years after they stopped taking them.

Lead author Dr Shelly Gray of Washington University said in a statement that patients should not stop taking their medications, but should talk to their doctor.

“Health care providers should regularly review their older patients’ drug regimens… to look for chances to use fewer anticholinergic medications at lower doses,” Dr Gray said.

The drugs are far more commonly used in the US, where a popular over-the-counter hayfever drug called Benadryl contains the possibly dangerous ingredient. Benadryl sold in Australia does not contain the chemical.

Australian doctors are well aware of the risks of prescribing the drugs. In 2013, a federal government body issued a caution to local doctors about prescribing the drugs.