Dr. Bonita Falkner Published study links obesity and sodium intake to elevated blood pressure in children

Presenter: Emily
Guest: Dr. Bonita Falkner
Guest Bio: Dr. Bonita Falkner from the Thomas Jefferson University in Philadelphia, Pennsylvania.

Segment Overview
Interview with Dr. Bonita Falkner, Thomas Jefferson University, Philadelphia, Pennsylvania


Health Professional Radio – elevated blood pressure in children

Emily: You’re listening to Health Professional Radio. This is Emily and my guest today is Dr. Bonita Falkner from the Thomas Jefferson University in Philadelphia, Pennsylvania. Dr. Falkner, thanks so much for speaking with me today.

Dr. Bonita Falkner: I’m glad to do that, Emily.

Emily: Now, let me ask you.  You’ve been studying hypertension in children for more than 25 years, is that right?

Dr. Falkner: That’s right.

Emily: Can you describe some of the changes that you’ve seen over the last two and a half decades?

Dr. Falkner: Certainly.  One of the first changes is it was often thought that hypertension was a rare condition in children.  Part of the problem was that blood pressure was not measured regularly.  It was difficult to measure blood pressure in children.  And we had no reference values so that we didn’t know really what was normal and what was abnormal.

We were left with the adult value for hypertension which was a blood pressure greater than 140 over 90.  We know now, once we have some good data on what’s normal blood pressure in healthy normal children, is 140 over 90 is extremely high, particularly for young children.  It’s even high for adolescents.

Once we knew what was normal, we know what is abnormal blood pressure. Based on that, we have been able to recommend topaediatricians to take blood pressure as part of routine healthcare that paediatricians and primary care doctors who take care of children do on a regular basis.  With more routine measurement of blood pressure, the paediatricians and other primary care doctors are identifying children with hypertension earlier.

Emily: I see.  You were part of the research team that published a study this week in the Journal of Hypertension.  Can you tell me about the findings of that study?

Dr. Falkner: Right.  There were three key findings.  Dr. Rosner, who was the lead author on the paper, has worked with the National Blood Pressure databases in children for a long time.  One of the major sources of data on blood pressure in children has done something called the National Health and Nutrition Examination surveys.  And this is done on a representative population of adults and children every two years, to gather data in which enables us to get an understanding of what the state of health of the population is.

There has been a trend.  Others have looked at previous NHANES data compared to more current NHANES, and they’ve had shownan increase in blood pressure among children.  That increase has been fairly concurrent with the increase in obesity in children that has been ongoing in the US.

So, Dr. Rosner wanted to look at more recent trends in blood pressure level, and factors that might be associated with changes in blood pressure.  He also showed an increase in blood pressure level in children and adolescents and the results, the factor that was contributing to this increase in blood pressure was obesity.

Emily: I see.

Dr Falkner: That had been shown before, so that wasn’t terribly new.  But he also found that it wasn’t just obesity, it was abdominal obesity, and that the waist circumference measurements in the database.  It was children who were gaining more belly fat were primarily associated with the high blood pressure.

Then the third thing that was perhaps the most unique finding was he examined the dietary data that was in the database, and found that the increase in blood pressure was also related to a higher salt intake.  That was probably the most important finding.  Therewas a lot of information and evidence to support the adverse effects of a high salt intake on blood pressure on adults, but it’s very difficult to find this in children.

So, that was probably the unique piece of information in this paper was the evidence that there is an adverse effect of a high salt intake on blood pressure in children.  It’s not because children are using a salt shaker too much, but it’s probably the salt that’s already added to foods in processed foods.

Emily: I see.  Are we really eating three quarters of our sodium intake because of processed foods?  Is that one of the things that I’m reading?

Dr. FalknerThat’s correct, that’s correct.  About at least 75% of salt intake is hidden.  You’re not aware of it.  It’s already in the processed foods, the fast foods, restaurant foods and so forth.

Emily: Are we really eating that much differently than we did 25 years ago, or are we just seeing the data now to support what was already there?

Dr. Falkner: I think what is different is that there has been a secular shift in how people eat, and we are eating much more foods – processed foods.  It’s convenient, it’s easy.  Some of the processed foods are relatively cheap.  I think that can be backed up by the food industry, with the products they sell.  Our diets have shifted to be more foods that have already had something added to them by the time we get them.

Emily: Right.  So, if a change isn’t made, then we’re going to see these numbers continue to rise among young people and adults?

Dr. Falkner: That’s a concern, but that’s likely.

Emily: I see.

Dr Falkner: There are efforts underway.  There’s an effort in England, an advocacy group that is trying to communicate with food manufacturers and restaurateurs and so forth to try and modify their recipes to lower the salt.  To some extent, the restaurants are receptive to this concern, but I think they have a long way to go to urge and get some changes in the processed food industry.

Emily: Right.  Are you seeing … well, obviously, the data in this study is a paediatric study but overall, is research suggesting that the problem is increasing more rapidly among children?  We hear a lot about childhood obesity.  Is this a problem that is across the age spectrum, or is it a developing concern among young people specifically for some reason?

Dr. Falkner: You mean across the age spectrum of children into adult?

Emily: Children and adult, right.  As we’re seeing a rise in childhood hypertension and obesity, is that consistent with the rate at which these problems are growing in adults?

Dr. Falkner: I would think there’s not a great deal of difference between what children eat and [inaudible 09:07] I mean the parents have something over what foods are bought and so forth.  But, you know, there’s a lot of food marketing to children, so that sometimes it is difficult for parents to totally control what comes in.

But what we say is we try and encourage parents to do and families to do, and what I do is try and encourage [indecipherable 09:39] to cook, at least part of the time, to cook something.  Use vegetables and fruits and fresh meats and grains, and cook.  Because if you cook, then you know what’s in the food.

Emily: Right, right.  Yes, I can certainly see that going forward a collaboration between a lot of different people including, obviously, nutritionists and other people is going to be necessary in order to make the kind of change that’s going to prevent this from being a lifelong problem for these kids.

Dr. Falkner: It’s a problem.  It tends to affect … the obesity and the high blood pressure tend to affect minority children more than the non-minority, but this trend towards processed restaurant food goes across all strata of the population.  It’s not limited to one group.

Emily: Right. Are you seeing other causes in addition, other factors that are playing a larger role for some reason? For example, are genetic factors risk factors for hypertension increasing for some reason?  Are there other environmental factors besides food?  Or are you thinking that this is really the primary thing that if we could control it, we could start to see these numbers go down?

Dr. Falkner: Right, with regard to genetics – and genetics is wonderful.  We’ve learned so much from genetics.  There are a few what are called monogenic causes to hypertension.  In other words, a specific gene abnormality that causes the kidney to retain more salt or some other mechanism that is off because of this genetic variation.

So, we know a few of those, but it’s been hard to find what gene or what collection of genes actually are the hypertensive genes.  We don’t know that every well.  But what we are learning is in the area called epigenetics, and that is a term that reflects the interaction between environmental factors, such as diet and [inaudible 12:18] and so forth, with certain genes, how the genes function.

We’re not going too … so far, it doesn’t look like we have found a specific gene that causes hypertension, and really our genetics, our genes, don’t change that rapidly after the increase in blood pressure and the increase in obesity and so forth.  Probably, it’s more of an issue of this interaction of environment, health behaviours, and certain types of patterns of genes that we have.

Emily: I see.  What I’m hearing from you is that the take away from all this, is this really the first study that gives data that suggests that there’s a link between the food and the high blood pressure, whereas in the past, we were seeing studies that suggested that perhaps high blood pressure in children was generally caused by some other disease, renal failure or something like that.

Dr. Falkner: Well, there is this condition, it’s called secondary hypertension, and that was the belief that when you find a child who has hypertension, it has to be secondary to something else, some other abnormality that they have.  You try and find that abnormality through diagnostic evaluation.

That still is something that has to considered when a child is found to be hypertensive, and they do require some basic evaluation to make sure they don’t have a kidney problem or a heart problem that is really causative.  But at least in adolescence, that’s less likely than the primary hypertension or the adult type of hypertension.

Emily: Right, thanks.  Thanks for the information.  You’re listening to Health Professional Radio.  This is Emily, and my guest today is Dr. Bonita Falkner from Thomas Jefferson University in Philadelphia, Pennsylvania.  Dr. Falkner, thanks so much for speaking with me today.

Dr. Falkner: I’m glad to do it.

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