* A personal superstition: Some people may wear a white thread around their wrist for personal reasons, like a good luck charm or to ward off negative energy. It's not a specific Russian tradition, but a common superstition in many cultures.
* A fashion trend: Some people, regardless of their nationality, might wear a white thread for a fashion statement, without any particular meaning attached to it.
* A religious symbol: In some Orthodox Christian communities, a white thread may be used for a symbolic purpose, like a reminder of prayer or a spiritual connection.
* A personal reminder: Someone might wear a white thread as a reminder of a specific event, like a birthday or a special occasion.
Without further context, it's difficult to say for sure what the white thread around a Russian wrist represents. If you have more information about the specific situation, it might be easier to determine its meaning.