Which of the following is a common cause of hyponatremia?

Hyponatremia, defined as a low concentration of sodium in the blood, can often result from an excess of water relative to sodium levels. Overhydration introduces an imbalance where the body's sodium is diluted due to the increased volume of fluid. This can occur when individuals consume excessive amounts of fluids, especially in the context of certain medical conditions, vigorous physical activity, or psychological disorders associated with water intake. The dilution of sodium leads to the resultant imbalance, making overhydration a significant contributor to hyponatremia.

In terms of the other options, while vomiting can lead to electrolyte imbalances, it typically results in a loss of sodium rather than overhydration. High sodium intake, conversely, is more likely to lead to hypernatremia, which is characterized by elevated sodium levels in the blood. Kidney disease can impact sodium regulation, but it usually reflects a different pathophysiological process compared to overhydration. Thus, overhydration stands out as a direct and common cause of hyponatremia.