Apart from verification of credentials, just find out whether your potential life partner smokes or not, for a new study has revealed that being married to a smoker can significantly raise your risk of a stroke.

Previous studies have indicated the dangers of stroke to smokers, but till now had not explored the high risk from passive smoking.

Now a team at Harvard University has found that even if one does not smoke, tying the knot with a smoker increases the chance of suffering a heart stroke by up to 72 per cent, the American Journal of Preventive Medicine reported.

"These findings indicate that spousal smoking increases stroke risk among non-smokers and former smokers. The health benefits of quitting smoking likely extend beyond individual smokers to affect their spouses," lead researcher Dr Maria Glymour wrote.

The researchers came to the conclusion after analysing the records of more than 16,000 people in the United States. They looked at people aged over 50, and their spouses, over a period of nine years.

The study found that if the person had never smoked, living with a smoker raised stroke risk by 42 per cent. If he or she had smoked at some point in their lives, but given up, the increase in risk was even higher, at 72 per cent.

The results were true after taking all other factors into consideration.

However, the study revealed that being married to a former smoker did not increase the risk, suggesting that this extra risk would fall away if the partner stopped smoking.