Which of the following is a common cause of obesity and diabetes in adults?

Hypothyroidism is indeed a common cause of obesity and diabetes in adults due to its impact on metabolic processes. When the thyroid gland is underactive, it results in decreased levels of thyroid hormones, which play a crucial role in regulating metabolism. This reduced metabolic rate can lead to weight gain as the body burns fewer calories. Additionally, hypothyroidism is associated with insulin resistance, which can contribute to the development of type 2 diabetes. The relationship between thyroid function and carbohydrate metabolism further highlights how an underactive thyroid can lead to higher levels of glucose in the bloodstream, ultimately resulting in diabetes.

In contrast, while acromegaly can lead to insulin resistance and altered glucose metabolism due to excess growth hormone, it is less common than hypothyroidism and typically presents with other notable symptoms and features that distinguish it from typical obesity-related causes. Postural orthostatic tachycardia syndrome primarily affects cardiovascular responses and does not have a direct link to obesity or diabetes. Hyperthyroidism, on the other hand, usually leads to weight loss and increased metabolic rate, which contradicts the relationship between hyperthyroidism and the development of obesity or diabetes in adults.