What environmental factor might contribute to maceration of skin around the buttocks?

Maceration of the skin occurs when it is exposed to excessive moisture, which leads to softening and breakdown. Urinary incontinence can significantly contribute to this condition because the constant presence of urine creates a moist environment that affects the skin's integrity. The moisture from urine can lead to skin damage, irritation, and increase the risk of pressure ulcers or infections in sensitive areas such as the buttocks.

In contrast, while prolonged bed rest can lead to pressure ulcers due to immobility, it does not directly cause the skin to become macerated unless there is additional moisture present. A high-fat diet is not related to skin maceration and typically has effects more related to overall health rather than skin integrity. Low ambient humidity might contribute to skin drying and cracking but does not produce moisture accumulation that results in maceration. Thus, urinary incontinence is the most relevant factor for the maceration of skin around the buttocks.