For males, taking part in team sports was associated with fighting and binge drinking, but also linked with lower levels of smoking and depression. For females, taking part in sports was associated with lower levels of fighting, depression, smoking, drug use and unhealthy weight-loss habits.
The question of particular interest is whether the "association" is a direct tie or more a set of behaviors that happen to occur in parallel.
The strength of peer support in a team sport environment could certainly increase the amount of peer pressure to participate in risky behaviors like drinking or fighting. I find it particularly interesting that the negative impacts don't cross genders which leads me to think that the social behaviors of boy's and girls within gender specific social structures like a sports team may be a key piece of the puzzle.
Males and females bond and interact in different patterns and with different priorities. These differences may drive riskier behaviors in males while promoting positive behaviors in females. It would be interesting to see someone examine the data from this study with an anthropological approach to better understand where the behaviors are initiating within the teams and what impact gender has on the resulting behavior.