New opportunities for detecting osteoporosis

Osteoporosis can be detected through low dose computed tomography (LDCT) imaging tests performed for lung cancer screening or other purposes. A study published in the Journal of Bone and Mineral Research found that such tests can identify large numbers of adults with low bone mineral density. The study included 69,095 adults from 14 cities across China who received a chest LDCT scan for the purpose of lung cancer screening in 2018 and 2019. Analyses of these scans revealed that the prevalence of osteoporosis among individuals older than 50 years of age was 29.0% for women and 13.5% for men, equating to 49.0 million and 22.8 million Chinese citizens, respectively. In women, this rate is comparable to estimates from standard bone density scans, but in men, the prevalence was double. "Our large scale, multicenter study of bone density measured from routine LDCT scans demonstrated the great potential of using LDCT for the opportunistic screening of osteoporosis as an alternative to standard DXA scans," said senior author Wei Tian of the Chinese Academy of Engineering and the Peking University School of Medicine. "Our study revealed the unexpectedly high prevalence of osteoporosis in men, which may impact on the management strategy of men in the future."

Brazilian researchers discover how muscle regenerates after exercise

Researchers at the University of São Paulo (USP) in Brazil have discovered that the muscle regeneration promoted by aerobic exercise is mediated by changes in oxygen consumption by satellite cells, also known as skeletal muscle stem cells. The discovery is expected to be used to help people recover from injury and combat the loss of muscle mass associated with aging. Previous research showed that weight lifting and other kinds of strength training increase the number of satellite cells. In aerobic exercise, muscle tissue is known to increase its capacity but the repair mechanisms associated with satellite cells had not previously been studied. The USP group found that aerobic exercise boosted the growth of satellite cells and that significant metabolic alterations lay behind the phenomenon. "We noted reduced oxygen consumption in satellite cells, whereas exercise raised the demand for oxygen in all other muscle tissue. This is the first time anyone has managed to observe how aerobic exercise influences mitochondrial metabolism in these cells and how this affects muscle regeneration," the researchers said. To understand the mechanism, the researchers said a number of experiments with animals at USP's Chemistry Institute. The findings are reported in an article published in Journal of Cachexia, Sarcopenia and Muscle. "We discovered at least part of the mechanism that led to improved muscle regeneration. Fuller knowledge is the first step to being able to intervene in the regeneration process in future," the researchers said. The findings refuted the researchers' initial hypothesis, which was that because aerobic exercise enhanced muscular oxidative capacity and satellite cells are anchored to the surface of skeletal muscle tissue, the oxidative capacity of satellite cells also ought to increase. The researchers now plan to investigate the effects of reduced mitochondrial oxygen consumption and the pathways involved in satellite cell self-renewal.

Different outcomes by race/ethnicity among patients with COVID-19 and rheumatic disease

Among U.S. patients with rheumatic disease and COVID-19, racial/ethnic minorities had higher risks of needing to be hospitalized and put on ventilators. The findings come from an analysis published in Arthritis & Rheumatology. The analysis included data on all U.S. patients with rheumatic disease and COVID-19 entered into the COVID-19 Global Rheumatology Alliance physician registry from March 24 to Aug. 26, 2020. A total of 1,324 patients were included, of whom 36% were hospitalized and 6% died; 26% of hospitalized patients required mechanical ventilation. Compared with white patients, Black, Latinx, and Asian patients had 2.74-, 1.71-, and 2.69-times higher odds, respectively, of being hospitalized. Latinx patients also had three-fold increased odds of requiring mechanical ventilation. No differences in mortality based on race/ethnicity were found. "Similar to the general population, Black, Latinx, and Asian individuals with rheumatic diseases are more likely to experience severe outcomes of COVID-19. These data suggest that the current pandemic will further exacerbate the health disparities that already exist for many patients with rheumatic disease," said senior author Jinoos Yazdany, of the University of California, San Francisco.