Teenagers who achieve good grades in school tend to smoke less, a new study has found.

Spanish researchers set out to determine how certain factors, such as education performance and parental permission to smoke, affected rates of the habit.

They questioned over 9,000 students in more than 200 schools. All had an average age of 16.

The study found a close link between smoking and academic performance.

"We have found that the use of tobacco is three or four times higher among those students whose academic performance is of a low level as compared to those who earn the highest grades," the researchers from Madrid explained.

Another issue which appeared to have a lot of impact on smoking rates related to parental tolerance. Students who did not have their parents' permission to smoke were 50% less likely to, compared to those who did have their parents' permission.

The study found no link between smoking rates and whether the children attended public or private schools. Also, the level of education their parents reached did not appear to affect the results. However, home environment played a major role.

"The incidence of teen smoking is greater in those homes where another family member is a smoker," the researchers found.

Details of these findings are published in the journal, Nicotine & Tobacco Research.