Excess weight during preschool linked to higher bone fracture risk
Preschool children who are overweight or obese have a higher risk of bone fractures during childhood than normal weight preschoolers, according to a study published in the Journal of Bone and Mineral Research. The study included 466,997 children with weight and height measurements at age 4 years who were followed for a median of 4.9 years. Fractures occurred in 9.20% of underweight, 10.06% of normal weight, 11.28% of overweight, and 13.05% of obese children. Compared with normal weight, overweight and obesity were linked with 42% and 74% higher risks of lower limb fractures, respectively, and a 10% and 19% higher risk of upper limb fractures, respectively. "In a cohort of almost half a million children from Catalonia, Spain, we have found a strong association between preschool overweight/obesity and the risk of fracture during childhood. More research is needed to further understand the mechanisms underlying this correlation" said senior author Daniel Prieto-Alhambra, of the University of Oxford, in the U.K.
Cells must age for muscles to regenerate in muscle-degenerating diseases
Exercise can only improve strength in muscle-degenerating diseases when a specific type of muscle cell ages, report a Hokkaido University researcher and colleagues with Sapporo Medical University in Japan. Their findings utilizing mice models were published in the journal Nature Communications. Idiopathic inflammatory myopathies are rare diseases that cause muscle weakness, inflammation, and fibrosis. In addition to drugs, exercise can be powerful therapy for some patients. But in cases of chronic inflammatory myopathy, exercise can actually induce inflammation and fibrosis in muscles. Scientists have been wanting to understand why exercise benefits some myopathies but not others. Researchers at Sapporo Medical University in Japan investigated why a type of muscle cell, called fibro-adipogenic progenitors (FAPs), responds differently to physical exercise depending on the type of myopathy. These cells are a key regulator of the muscle stem cells needed for regeneration. They investigated what happens when mice with myopathy exercise. In mice with acute muscle injury which simulates idiopathic inflammatory myopathy, they found FAPs initially increased but then returned to pre-damage levels after seven days. These FAPs eventually died and were cleared by cell-eating immune cells called phagocytes. In mice with chronic inflammatory myopathy, FAPs continued to proliferate for 14 days and were resistant to cell death and clearance by immune cells. Investigating further, the team found that FAPs in mice with acute muscle injury showed strong signs of aging after exercise while FAPs in mice with chronic inflammatory myopathy didn't. They also found that normal FAPs induced regeneration of muscle cells after acute muscle injury while FAPs lacking a cellular aging-inducing factor didn't. These results together showed the aging of FAPs after exercise is necessary to establish a state of regenerative inflammation that induces muscle regeneration. Additionally, the combination of exercise and administrating drugs which induce cellular aging restored FAP aging and improved muscle function and regeneration in mice with chronic inflammatory myopathy.
COVID-19 pandemic may exacerbate childhood obesity
Public health scientists predict that school closures due to the COVID-19 pandemic will exacerbate the epidemic of childhood obesity in the U.S. Andrew Rundle, associate professor of epidemiology at Columbia University Mailman School of Public Health, and colleagues expect that COVID-19-related school closures will double out-of-school time this year for many children in the U.S. and will exacerbate risk factors for weight gain associated with summer recess. The perspective article appears in Obesity, the journal of the Obesity Society. In many areas of the U.S., the COVID-19 pandemic has closed schools and some of these school systems are not expected to re-open this school year. The experiences in Hong Kong, Taiwan, and Singapore suggest that social distancing orders if lifted after short periods will have to be periodically reinstated to control COVID-19 flare-ups. While much has been written about poor food and lack of physical activity in schools, the data show that children experience unhealthy weight gain primarily during the summer months when they are out of school. Unhealthy weight gain over the summer school recess is particularly apparent for Hispanic and African-American youth, and children who are already overweight. "There could be long-term consequences for weight gained while children are out of school during the COVID-19 pandemic," says Rundle, who specializes in research to prevent childhood obesity. "Research shows that weight gained over the summer months is maintained during the school year and accrues summer to summer. When a child experiences obesity, even at a young age, they are at risk for higher, unhealthy weight, all the way into middle age."