HEALTHDAY NEWS WATCHING your team win a major sporting event that ends in a close score can be thrilling, but there may be a drawback: aggressive, testosterone-fuelled driving by victorious fans.

A new study has found that traffic deaths at the game site and the hometown of the winning team increase significantly when the “nail-biter” game is over.

Researchers at North Carolina State University examined traffic deaths that occurred after 271 professional and college football and basketball games played between 2001 and 2008.

The analysis included traffic deaths that occurred in the area where the game was played, as well as in the hometowns of the winning and losing teams.

As part of the study, a panel of experts was asked to rate how close a game was on a scale of 1 to 5, with 5 being a nail-biter and 1 being a blowout.

The investigators found a s i g n i f i c a n t increase in traffic deaths following close games, and games that were nail-biters were far more likely to be associated with fatal accidents than games that were blow-outs.

In fact, each increase in the rating was associated with a 21 percent increase in traffic deaths at the game site.

Traffic deaths were 133 percent higher after a nail-biter than a blowout, the researchers explained in a university news release.

But the increase in traffic deaths occurred only in places where there were winners — the site of the game and the winning team’s hometown, they noted.

“This pattern of results is important in that it suggests that the cause of the relationship might be associated with competition-induced testosterone,” lead author Stacy Wood, a professor of marketing at North Carolina State University, said in the news release.

“During a close game, testosterone increases for the fans as well as the players — that has been established by previous studies,” Wood said.

“After the game, testosterone levels drop for the losing side, but spike for the winning side.

Because testosterone is linked to aggressive behaviour and potentially aggressive driving, we hypothesize that this may play a role in the increased number of traffic fatalities in areas with a high proportion of winning fans.” The study is slated for publication in an upcoming issue of the Journal of Consumer Research.