Osteoporosis in chronic obstructive pulmonary disease.

Sir,

Hattiholi and Gaude studied the ‘prevalence and correlates of osteoporosis in chronic obstructive pulmonary disease (COPD) patients’ and concluded that, ‘as the severity of COPD increased, the risk of osteoporosis increased.’[1] In fact, this observation was seen not only in India, but also in other countries. Watanabe et al. recently reported ‘a high prevalence of osteoporosis in Japanese male COPD patients and a strong inter-relationship between the two diseases.’[2] Evans and Morgan noted that this was a systematic nature of chronic lung disease.[3] In addition, Sharif et al. reported that the presence of osteoporosis was a risk factor for early re-admission with COPD.[4] However, an important consideration was the exact pathophysiology. A recent report by Moberg et al., showed no genotype–phenotype relationship.[5] This meant that the observation might be due to the environmental factor. Of interest, in most studies, including in the present study by Hattiholi and Gaude, there was no complete control of the confounding factor. In addition, there was no control group. A high prevalence of osteoporosis in this setting might be seen in cases either with or without COPD.