In osteomalacia, all are true except

In osteomalacia (vitamin D deficiency in adults), serum calcium is typically low or low-normal due to secondary hyperparathyroidism (PTH attempts to maintain calcium by increasing bone resorption). This makes increased serum calcium the FALSE statement and the correct exception. The other options are true: alkaline phosphatase is increased (due to high bone turnover from PTH stimulation and osteoid formation), Looser's zones (pseudofractures) are pathognomonic radiological features, and proximal myopathy is a common clinical manifestation due to vitamin D's role in muscle function.