Osteoporosis is responsible for more than 2 million fractures every year. What it feels like: Most people do not know they are osteoporosis until they experience a fracture. Who is affected? Women are more prone to osteoporosis and the condition is most common during and after menopause when bone calcium is lost at an accelerated rate. How common is it? Approximately 10 million Americans have osteoporosis. Risk factors: