Researchers studied over 8,000 schoolchildren in Mongolia for three years to understand why some kids break bones more often than others. They found that boys break bones about twice as often as girls, and older kids have more fractures than younger ones. Interestingly, smoking and family wealth also played a role in fracture risk. The study also tested whether a special ultrasound scan could predict who would break bones, but it didn’t work as well as doctors hoped. These findings help us understand bone health in children living outside Western countries.

The Quick Take

  • What they studied: How often children in Mongolia break bones and what factors make some kids more likely to have fractures than others
  • Who participated: 8,348 schoolchildren aged 6-13 years living in Ulaanbaatar, Mongolia. A smaller group of 1,456 children also had special ultrasound scans of their bones.
  • Key finding: About 25 out of every 1,000 children broke a bone each year. Boys were twice as likely to break bones as girls, and the risk increased with age, peaking around age 14. Smoking and lower family wealth increased fracture risk, while having parents who owned their home lowered it.
  • What it means for you: If you’re a boy or a teenager, you may want to be extra careful during sports and activities. The study suggests that family economic status and avoiding tobacco may help protect bones, though more research is needed to confirm these connections.

The Research Details

This study used information collected from a larger research project where Mongolian schoolchildren received either vitamin D supplements or a placebo (fake pill) for three years. The researchers tracked which children broke bones during this time and looked for patterns. They used a special ultrasound machine that measures how fast sound travels through bone—a test called radial speed-of-sound (SOS)—to see if it could predict who would break bones. They then used statistical methods to compare fracture rates between different groups of children, adjusting for factors like age, sex, and smoking.

Understanding bone fractures in children from non-Western countries is important because most previous research focused on Western populations. This study helps doctors and public health officials understand whether the same risk factors apply everywhere. Testing whether the ultrasound scan predicts fractures is valuable because it could help identify high-risk children early if it works.

This is a large study with thousands of participants followed over several years, which makes the results more reliable. The researchers carefully tracked fractures and used proper statistical methods. However, because it was a secondary analysis (using data collected for a different original purpose), some information may have been limited. The study was published as a preprint, meaning it hasn’t yet gone through the full peer-review process that published journal articles undergo.

What the Results Show

Over three years, 614 fractures occurred in 521 children. This means about 25 children out of every 1,000 broke a bone each year. Boys had significantly more fractures than girls—about twice as many. For every year older a child was, their fracture risk increased by about 18%. The highest fracture rates occurred around age 14, where boys had about 87 fractures per 1,000 boys per year, while girls had about 25 fractures per 1,000 girls per year. Children who smoked tobacco had more than twice the fracture risk of non-smokers. Interestingly, children whose parents owned their home (suggesting higher family income) had lower fracture risk than children whose parents rented.

The ultrasound scan of bone quality (radial SOS) did not help predict which children would break bones. This was surprising to researchers because this test works better at predicting fractures in some other populations. This suggests that bone quality alone may not be the main reason why some Mongolian children break bones more often.

The overall fracture rate in Mongolia (25 per 1,000 per year) is higher than what researchers have found in Western countries, suggesting that Mongolian children may face different risk factors or environmental conditions. The finding that boys break bones more often than girls matches what’s been seen in Western studies. However, the strong connection between smoking and fractures in children is notable and may reflect different smoking patterns or social factors in Mongolia compared to Western countries.

The study only included children in one city (Ulaanbaatar), so results may not apply to rural Mongolian children or other countries. The ultrasound bone scan was only done on about 1,500 of the 8,348 children, so conclusions about that test are less certain. The study couldn’t prove that smoking, wealth, or other factors actually cause fractures—only that they’re connected. Some fractures may not have been reported or recorded. The study was originally designed to test vitamin D supplements, so it wasn’t specifically designed to study all fracture risk factors.

The Bottom Line

Boys and teenagers should take extra precautions during sports and physical activities to prevent falls and injuries (moderate confidence). Avoiding tobacco smoking is important for bone health and many other health reasons (moderate confidence). Families should ensure children get adequate nutrition and calcium for bone development, though this study didn’t directly test this (general recommendation). If you’re concerned about your child’s bone health, talk to a doctor rather than relying on the ultrasound bone scan alone, since it didn’t predict fractures in this population (moderate confidence).

Parents of boys and teenagers should pay special attention to injury prevention. Young people who smoke should consider quitting for bone health and overall wellness. Healthcare providers in Mongolia and similar settings should be aware that fracture rates are higher than in Western countries and may need different prevention strategies. This research is less directly applicable to children in Western countries, where fracture patterns may be different.

Bone health improvements from better nutrition or reduced smoking take months to years to show effects. Injury prevention through behavior changes (like wearing protective gear) can reduce fractures immediately. If a child has already broken a bone, healing typically takes 6-8 weeks depending on the type of fracture.

Want to Apply This Research?

  • Track physical activities and any falls or injuries weekly, noting the type of activity and whether protective gear was used. For teens, track tobacco use if applicable. Monitor any new bone pain or swelling that might indicate a fracture.
  • Set reminders to wear protective gear (helmets, wrist guards, knee pads) during sports and high-risk activities. For users who smoke, use the app to track quit attempts and set goals to reduce or eliminate tobacco use. Log daily calcium-rich foods and physical activity to support bone health.
  • Create a monthly summary of injury incidents and identify patterns (which activities cause most injuries, which times of year are highest risk). Track changes in physical activity levels and protective gear use over 3-6 months. For tobacco users, monitor reduction progress toward quitting. Share trends with a healthcare provider during annual check-ups.

This research describes patterns in one population of Mongolian children and may not apply to all children everywhere. The study shows connections between certain factors and fractures but doesn’t prove that these factors directly cause fractures. The ultrasound bone scan did not predict fractures in this study, so it should not be used as a screening tool based on this research alone. Always consult with a qualified healthcare provider about your child’s bone health, injury prevention, and any concerns about fractures. This information is for educational purposes and should not replace professional medical advice.