London: Bad habits, which increase heart disease risk, could also be affecting brain function in people as young as 35, a study has suggested.
Dutch researchers examined almost 3,800 people in the age group of 35-82, testing memory, planning and reasoning.
High cholesterol and heavy smoking were linked to bad performance in the tests across all ages.
The researchers from the University Medical Centre in Groningen said that there was proof that decline in brain function can be seen by the age of 45.
To see if signs could be detected even earlier, the research team assessed participants` mental abilities using a comprehensive test and also looked at risk factors for cardiac problems like smoking, high cholesterol, high blood pressure, diabetes and being overweight, which enabled them to compile a "risk profile" for each participant.
The people who had the most serious risk for cardiac problems fared around 50 percent worse on the cognitive tests than others - across the age range.
And people, who smoked one to 15 cigarettes per day had a cognitive score, which was on average two-point-four points lower than non-smokers and those who smoked more than 16 cigarettes a day had on average a three-point-four point lower score, the BBC reported.
Dr Hanneke Joosten , who led the study, said that most people know the effects of heart risk factors like heart attack, stroke and renal impairment, but do not realise that it also affects cognitive health.
The research has been published in the journal Stroke.