What makes the health worst?

Lack of sleep maybe. People tend to insomnia. I guess so.

It might worsen to to the body's lack of positive response to the medication or the environment around them. There is sometimes a poor diet that continues and so they disease or illness does as well. I don't think there has ever been a recurrence of cancer too quickly if the diet gets better with only eating organic veggies and fruits and trying to stay away from red meat, sugars, too many unhealthy fats, salt and processed food.

I think it's stress most of the time and getting too focused at health. We know more so we worry more.

If it's a infection then there might be a parasite that grows too rapidly and the antibiotics and white blood cells are either too few or too weak to fight it off, or maybe it's rapidly breeding.