A 52-year-old woman with a BMI of 31 is diagnosed with osteoarthritis of the knee. The nurse practitioner (NP) instructs the woman that weight loss will help minimize both pain and functional loss. Which of the following most closely explains the NP's advice to lose weight?

Choice A reason: While true, this choice is a general health benefit and does not directly explain the reduction in knee pain or functional loss. Choice B reason: This choice is correct because mechanical load on the knee joint increases disproportionately with body weight. Even a small amount of weight loss significantly reduces joint stress, thereby improving pain and function in osteoarthritis. Choice C reason: Reducing cardiovascular strain is beneficial but does not directly impact knee joint load or osteoarthritis symptoms. Choice D reason: Preventing falls is important but is an indirect benefit; the primary mechanism for pain reduction is decreased mechanical load on the joint.