What is a Bone Age?

Bone age is helpful in assessing a child who is shorter or taller than predicted based on parent heights or if a child has early or late pubertal changes. It is simply an x-ray of the child's hand and wrist. It involves minimal radiation and does not hurt. The bone age can help us approximate how much longer a child will grow and the expected height, but does not tell us why a child is shorter or taller than expected or hitting puberty at an unexpected age.

A delayed bone age means that the bones think they are younger than the child actually is. This can mean catch up growth after peers have stopped growing. A delayed bone age can happen for many reasons, but a common one is due to late puberty and can run in families. A history, physical exam and possibly labs can help asses the reason for delayed bone age.

If a child has an advanced bone age it means the bones appear older than the child's actual age. With this we expect them to stop growing earlier than most kids. This means that even if they are tall for their age, they could end up shorter than average. This is often associated with early puberty and childhood obesity. An advanced bone age needs further evaluation to identify the cause.

If the bone age equals the actual age, you can estimate the final height to be about the same percentage as the current height.

We often repeat bone ages to see if they are changing at a different rate than the child grows.

Radiologists and endocrinologists use books with x-rays of standard bones of various age groups to assess which age the child's x-ray most closely resembles. Since there are different bones that can develop at different rates, it is possible that two doctors will assign a different bone age. It is not an exact science, but can give a good estimate of how much longer a child may grow. 

The photo above is from Amazon's bookstore. You can see how the bones of the youngest hand on the left are very different from those in the hand on the right. The radiologist or endocrinologist finds the image that is most like the child's x-ray and call it that bone age. 

In the boy growth charts pictured below, the top set of lines is the height (stature) for age chart. The bottom set is the weight chart. The ages that are used to plot a height at a given time are listed at the top and bottom. The heights are listed on the right and left of the graph. The middle line is 50%, which reflects a height of 50% (taller than half/shorter than half of boys of the same age). The other lines are also labeled for their respective height percentiles on the far right. Hopefully this looks familiar because you've seen a graph like this at your child's doctor. If you haven't, be sure to ask to see it next time you're there.

There are many "normal" heights, usually determined by genetics. Tall parents tend to have tall kids, short parents have short kids. There is no "correct" height or "best" height, the percentiles simply give us a way to follow the growth over time and estimate final adult height if a child hits puberty at a typical age (early puberty stops the growth early, late puberty allows for later growth).

In Figure 1, I filled in a fictitious child's heights with blue dots. You can see that from 3 to 5 years this boy was at the 50th percentile for height. That means he was taller than half the boys his age and shorter than half. The fact that he's in the middle doesn't make it "normal" it just means that if his parents are average height, he is growing as expected because it's consistent year to year and he is of average height like his parents. At 6 years, he dropped to the 25th percentile, and at 8 years he fell to the 10th percentile. This consistent drop in growth often triggers a physician to look for reasons of the drop. Maybe the parents are both very short. Maybe there is a medical problem. Or maybe there is a family history of people having late growth spurts (something called "constitutional growth delay"). Treatment (if needed) varies depending on the cause.

Figure 1

The red arrow on the right marks the actual height at 8 years (blue) at about 47 inches (120cm). For this fictitious child, the bone age is 7 years, and if you plot 47 inches (the actual height at the time) at 7 years (the bone age), you will see this white dot is at the 50th percentile and marked by the red arrow on the left. A delay in bone age often coincides with a late growth spurt. I finished out the growth plots, and this kiddo actually fell more (down to the 5th percentile) before he hit a late puberty and grew into late teens/early 20s to hit a final height at the 50th percentile.

In Figure 2 below a fictitious boy is tall for his age early on. At 6 years old his height (black dot) is at the 97th percentile (he is taller than 97 out of 100 of boys his age) at about 49.5 inches (125.5cm). His bone age at the time (red dot) is 8 years 6 months, which is at the 25th percentile for height. A year later he is off the height chart, taller than over 97% of boys his age, but the bone age is 10 years 9 months, again at the 25th percentile. This chart shows an early growth spurt (as he looks taller than his peers) but an early puberty and a slowed growth faster than other boys. His final height is only at the 25th percentile, much shorter than his early heights would have predicted.

Many parents are super excited when their children are tall and can't comprehend when I talk about the possibility that it might not last. (I typically discuss this if both parents are short but the child is tall, if I see signs of early puberty, or if the child is obese - especially if parents are not as tall as the child's height predicts.) The bone age does not give a reason for the altered growth rate, but can help identify a need for further evaluation and treatment if indicated.

Figure 2

Bone age is difficult to understand, and I hope this helps parents understand with some pictures. I completely made up these growth charts. They do not reflect any real patient or any real diagnosis. They are solely to illustrate how we estimate the bone age on the growth chart to help assess final predicted height. The reasons behind altered growth patterns are many and might require further evaluation.

Take home point: At every well visit your child should have a height and weight measured. If the yearly growth accelerates too fast or slows, talk to your doctor about possible reasons. If a bone age is done, you can use a growth chart to put the bone age in at your child's height (instead of actual age) and see how tall the final height estimate would be. It isn't a guarantee, but can be helpful.

My child won't eat... what should I do?

I hear from worried parents often that their kids won't eat. There are many reasons for this. Usually as long as a child is hydrated, gaining weight appropriately, and getting a variety of nutrients, I am not worried.

Some reasons kids don't eat:

• They're really getting enough food, parents just have unrealistic expectations. This is very common. Portion sizes are smaller than many parents think. They vary with age and size of a child as well as his activity level. If your child is growing well and has plenty of energy throughout the day, why should he eat more? Kids tend to eat small meals frequently and even on holidays they don't overeat like the adults tend to do. When offering snacks, think of them as mini meals to help balance out the nutrients of the day. Don't let them snack all day long though or they'll never really be hungry. Schedule meals and snacks and allow water in between. We have an obesity epidemic in this country, so if you're comparing your child to another child, chances are that your thin child is healthy and normal, but the other one is one of the 30% who is overweight. Or maybe not. It doesn't matter. Just be sure your child is getting a proper variety of nutrients, he should determine how much to eat. Talk to his doctor about his growth at regularly scheduled well visits (more often if you're concerned) to be sure it's appropriate.
• They're sick and it's temporary. When kids are sick they lose their appetites. This is normal. It usually returns with a vengeance when they're feeling better. They need to drink to stay hydrated and can eat what they feel up to it, but don't force it. See their doctor if you're worried.
• It's a new food and they just aren't sure yet. I encourage that kids over 3 years old take one bite of a food. Kids often hear me say, "taste a bite without a fight." The bite needs to be enough that they taste it. If they like it they can keep eating. If they don't want more, resist trying to convince them to eat more. Allowing them to take ownership of the decision of what to eat empowers them. Kids like power, right. Give it to them while modeling healthy eating behaviors yourself. They learn from what you do, not what you say -- and not from what they're forced to do. When preparing a new dish, include familiar foods they like to balance out the meal so they can enjoy at least something on the plate.
• They're picky eaters. Aren't they all? Most kids go through phases where they love a food then they suddenly dislike it. They might dislike a certain texture or a whole food group. While there are kids with real problems eating, most picky eaters can be encouraged to eat a healthy variety of foods as described above. Some children really suffer from being overly restrictive. Children with autism, sensory problems, food allergies, and other issues are not included in this "typical" picky eater category. A great series of blogs on picky eaters (typical and more concerning) is found on Raise Healthy Eaters. 
• They're more interested in something else. Make meals an event in itself. Sit together and talk. Turn off the television. Put away your phone. Have everyone focus on the meal, which includes the food and the conversation. Try to keep the conversation pleasant and not about the food. Take the pressure off eating!

In general, parents should choose what foods kids are offered so that there's a balance of nutrients, but kids determine how much they eat. If they're hungry, they'll eat. If they're not hungry, they shouldn't eat. Learning to eat when not hungry is something that causes many of us to struggle with weight. Most kids are able to limit intake to needs. Don't force them to change that great quality!

For more, see my other blogs on the subject:

• Nutrition for the Picky Eater
• Taste a Bite Without a Fight
• Food Strike!
• Kid's Weight Is Weighing On My Mind

What kids need to be able to do to leave the nest...

photo source: Shutterstock

It's graduation season, which has me thinking of all the ways our kids grow over the years. They're born, then just a few years later they are in kindergarten. In just a blink of the eye they get a locker in middle school. Then high school is over. The world awaits...

Where does the time go?

I have one who will be starting high school next year, and have spent a lot of time reflecting about at all he's learned and what he needs to learn to be successful, independent, healthy and happy.

I have never really thought that school is about learning the actual subjects. It is more about learning how to learn. How to organize. How to be responsible. I have always told my kids I don't care what grade they get as long as they learn what they need to and do their best.

Home life is also a process of learning. We learn how to live healthily and respectfully with others. We learn to take care of ourselves. We learn to be responsible with money. Ideally we learn to argue a point without losing control of our emotions or being hurtful.

In all of this reflection, I came up with a list that I have shared with my kids, and I invite you to share it with yours.

Things you should be able to do independently before leaving home:

Good hygiene habits

• Brush teeth twice daily. Floss once a day. 
• Shower or bathe daily. Wash hair as needed for oil control. 
• Wash hands often. 
• Shave as needed. 
• Flush.
• Brush hair at least daily and get a hair cut regularly. 
• Clip and groom nails regularly, fingers and toes. 
• Use personal hygiene products correctly, including: deodorant, facial acne cleansers, etc. 
• Wear clean clothes and change underclothing daily. 

Healthy habits

• Get adequate sleep to wake fresh and ready for the day. Set an alarm and get up on your own. 
• Eat healthy foods and limit junk food and sodas. Be able to prepare simple healthy meals. 
• Take vitamins daily. 
• Understand common over the counter medicine indications and how much to take.
• Understand why you are taking medications (if you are), how to take them, and what is needed to get more -- is it over the counter or a prescription medicine?
• Know your medical history, including any allergies and chronic health care problems.
• Know how to take care of common injuries until they are healed. 
• Exercise regularly, at least 3 times a week. 
• Develop healthy strategies to handle stress. 

• Journal 
• Prayer or meditation 
• Sketch or other artwork
• Talk to someone openly—don’t hold bad feelings in! 
• Take a long bath 
• Think before speaking 
• Deep breathing 
• Laugh 
• Exercise 
• Schedule down time 
• Think about the problem from different points of view 
• Break big projects into small parts to be able to complete in parts 
• List the good things going on and be positive 
• Avoid overscheduling
• Learn to say "no"

• Enjoy social interactions as well as alone time. 
• Exercise the brain by doing puzzles or reading.

Things to learn

• How to cook a healthy, balanced meal. 
• How to grocery shop on a budget to incorporate nutritional balance.
• How to properly clean dishes and tidy up the kitchen after eating.
• How to balance a check book, make a budget, and pay bills on time.
• How to do easy repairs around the house.
• Understand health insurance plans - how to get them, what they cover, what is excluded.
• Basics of money investment, retirement planning, savings.
• What to do in case of a road side emergency.
• Important numbers (doctor, dentist, insurance, etc).
• How to do laundry.
• How to clean a bathroom, use a vacuum, and dust.
• How to sew basic clothing repairs (buttons, hems, etc).
• How to get help when needed.
• How to apply for a job and build a resume.
• Choose words carefully: they can build someone up or crush someone down. 
• Drugs and alcohol should be treated with respect and used only with good judgment. This judgment should take into consideration laws and safety. Our brain does not fully develop until the early/mid 20s and early use of drugs or alcohol increases the risk of addiction.

Be a good friend and responsible family member

• Be clear with plans: Look at the family calendar when making plans. Get permission from all parents involved; let family know where you will be and when you will be home. 
• Keep a phone available to be able to call when needed. Answer calls/texts from parents! 
• Treat everyone with respect: family, teachers, friends, and strangers. 
• Require that others treat you with respect. 
• Do random acts of kindness occasionally. 
• Volunteer regularly.
• If you feel unsafe, leave the situation. Tell a trusted adult as soon as possible. 
• Do only things you and your parents will be proud of. 

Things to do to show you are getting ready to leave the nest...

• Complete assigned homework and chores without reminders or nagging. 
• Keep your room picked up and clothes off the floor. 
• Hang your towel to allow it to dry between uses. 
• Clear dishes from the table. 
• Clean up after projects or play. Return all things to their proper place after using them. 
• Throw all trash in the trashcan. Recycle things that are recyclable. 
• Responsible use of cell phone, computer, and other electronics. Turn off before bedtime to allow uninterrupted sleep. 
• Spend and save money responsibly. Never spend more than you can afford. Use credit cards wisely.
• Take pride in your work: schoolwork, chores, job, and helping others. Do it to the best of your ability and ask nicely for help as needed. Recognize that work is not always fun, but necessary. Doing tasks with a good attitude will help. 
• Time organization skills: Do not procrastinate until the last minute. Plan ahead and do big projects in small steps. Be prepared with all materials you will need for a project and ask in advance if you need help acquiring items. Use tools (apps, calendar, check lists). 
• Take care of your things. Keep them in proper working order, clean, and put away. 
• Drive responsibly. 
• Accept consequences with grace. 
• Earn trust. 
• Know when to trust and follow others and when to take your own path. Make independent decisions based on your own morals. Have the courage to say "no" if something goes against your beliefs.

Too Little Sleep in Athletes

I am very concerned on many levels about late nights required for local sport programs from a parent perspective and as a pediatrician.

Many physical and emotional problems have been linked to sleep deprivation.  I see many kids who struggle in school and at home with behavior and learning problems that are directly related to loss of adequate sleep.  Poor sleep is also related to obesity, poor growth, depression, anxiety, poor school performance, and so many other issues.  Sleep is needed for release of growth hormone, which is needed for bone and muscle growth, muscle repair, fat burning, and learning.  Sleep loss leads to poor attention spans, inconsistent performance, decreased aerobic endurance, delayed response times, and increased illness, and will therefore affect their game!  There is increased risk of injury in these tired athletes.

You can argue that one late night a week will not have devastating consequences, but I disagree. We have all heard that consistent bedtimes are important for sound sleep.  Ironically sleep deprivation often leads to insomnia and more sleep problems. You cannot sleep "extra" to bank sleep hours.  Kids will often sleep in on weekends to attempt to catch up on the sleep hours missed during the week, but that means a week of struggles emotionally and physically.  It also gets their sleep routine off balance, which again contributes to poor sleep.

It is recommended to exercise at least 2-3 hours before bedtime because exercise is stimulating, making it difficult to fall asleep after exercise until the body temperature and metabolism return to normal.  Yet I find that many school aged kids have practices and games in the late evening into night hours.

School aged kids up to 12 years of age need 9-11 hrs of sleep per night to function adequately.  Practices and games late in the evening shortchange their night's rest by far too many hours.  Don't forget to consider that the time to settle down after the game is up to 3 hours. The following day they are likely to have problems at school.  An overtired child often has MORE problems getting to sleep, which affects the rest of the week.  These younger kids tend to have a lot of noticeable behavior and learning problems. Many are misdiagnosed with ADHD and treated with medication, when all they really need is better sleep. It is simply not acceptable to set them up for this failure.

As kids enter middle school they often need extra sleep due to puberty.  (Growth hormone is released during sleep.)  Unfortunately, school tends to start earlier and their game/practice times are often later, meaning they might be getting up just a few hours after they are falling to sleep.  Do we really want to affect their growth during these important years? 

No wonder many middle and high schoolers fall to sleep in class and struggle with falling grades, irritability, depression, and more.

Kids shouldn't have a hard time getting up in the morning.  If they are, it's a sign of not enough sleep!

I should also include coaches and parents in this, since we will be required to teach and transport these kids. Adults will fall short of their recommended 7-9 hrs of sleep, which affects mood, weight gain, and attentiveness.  This affects not only health, but also home and office life.  Can you wake up before your alarm?  If not, can you get to bed earlier?  That is a healthier choice than adding an extra cup of coffee or energy drink to your day.

We as parents and coaches want our kids to succeed in all areas of life. We want to give them the tools they need for this, which must include proper sleep.  Practice and game times on school nights must take into consideration the sleep requirements of these kids.  I do not want to be responsible for allowing  my child to be out late on school nights, therefore contributing to increased risk of poor school performance, behavior issues, immune deficiencies, depression, growth and obesity, and all the other known consequences of poor sleep. Once these issues surface it is too late to prevent them and the snowball effect begins!

The question: What can parents do?????