A tricky question since boredom is a mental state. Usually it is triggered by an uninspiring, monotonous environment and/or certain brain chemicals like dopamine (more on dopamine). People who produce less dopamine, or are less sensitive to it, are bored more easily.
People bored for a very long time can suffer from clinical depression, which surely reduces lifespan. Other boredom sufferers have ADHD (attention deficit hyperactive disorder) and extreme ways of combating boredom can be equally dangerous. They could abuse drugs and alcohol or seek thrills in risky sports. Others could become sexually promiscuous. All of these behaviours reduce lifespan.
Send your questions to firstname.lastname@example.org and we’ll find out if it’s the truth or just a fib!