Humidity

Defoliation lowers humidity because it reduces the plants respiration(uptake of water/nutrients). Too much defoliation and you'll be stunting the plant as the leaves are it's solar panels. I'd advise you to get more air exchange in your tent to lower humidity. Circulation fans inside the tent can also help keep the plants healthy in a higher humidity environment. Defoliation would be the last way I'd want to address a humidity issue.

Each leaf is transpiring into the atmosphere. Depending on your set up this is somewhat proportional to the humidity in the tent. Moving air helps and obviously ambient RH/ temps around the tent are crucial. That said, don’t go stripping leaves just to bring down humidity.. it will likely effect your grow negatively