Asthma can feel like a mystery, but a new review points to a mix of genes and environment. It says the genetic variants we know about so far explain only part of why asthma runs in families. That means other factors matter a lot.
The review also highlights air pollution, especially tiny particles called PM2.5. It suggests that breathing in PM2.5 may raise the chance of asthma, especially for people who are already genetically susceptible.
This review looked at many studies but did not report a specific group of people. It did not measure how strong the effects are or how often they happen. It also did not report any safety issues, since it was not a treatment study.
The big picture is that asthma risk comes from a mix of genes and environment. We still have more to learn about how these pieces fit together.