The guidelines are being issued the guidelines as part of a voluntary initiative, in response to the Government's "prime minister's challenge on dementia" report. It aims to deliver improvements in dementia care for the 670,000 people in the UK diagnosed with the condition.
Additional issues will also tackle other "vulnerable" members of the public, including those with a limited understanding of English and those with mental health issues.
Guidelines will instruct telemarketers how to identify and manage a call with someone they believe is unable to make an informed decision.
The DMA’s contact centres and telemarketing council has produced the guidelines in conjunction with charities including Alzheimer’s Society, Dementia Action Alliance and Rethink Mental Illness, alongside companies including BT, trueCall, nPower, Blue Donkey, KMB Telemarketing and ReynoldsBusby Lee.
Jeremy Hughes, chief executive of the Alzheimer's Society, warned that the guidelines were necessary because "someone with dementia may be confused during a call and sign up for a product they don’t need or can’t afford".
The DMA is also rolling out an ongoing programme of education and advice in support of the industry’s adoption of the guidelines.
Elaine Lee, chair of the DMA contact centres and telemarketing council, said: "The marketing industry needs to increase its efforts to ensure that companies can identify vulnerable consumers and understand how best to meet their needs."
Currently the telemarketing industry comprises more than 5,000 call centres and employs over one million people, according to the DMA.