A recent study in the Journal of Clinical Endocrinology & Metabolism found that approximately one out of 200 Taiwanese who used oral alendronate long term for osteoporosis developed osteonecrosis of the jaw (ONJ). In comparison, among a group treated with raloxifene for osteoporosis, only one out of 1,882 developed ONJ. Risk factors for developing ONJ among alendronate users included diabetes, RA, and exposure to the drug for more than three years.
Although this study reinforces an association between oral bisphosphonates and jaw osteonecrosis, it also demonstrates that this adverse effect is uncommon. While the incidence of ONJ in this study was 7 times higher with alendronate than with raloxifene, the incidence rate of ONJ attributed to alendronate use was only 283 per 100,000 persons per year. The increased relative risk with alendronate is worth noting, but the absolute risk remains low, and for people with osteoporosis, the fracture risk-reduction benefits of bisphosphonates continue to outweigh the risk of jaw osteonecrosis.