Thursday, October 25, 2018

Tooth loss can indicate malnutrition, Rutgers study says


Older adults are at risk for both impaired oral health and malnutrition, according to a study by Rutgers University researchers.

The study, recently published in the Journal of Aging Research and Clinical Practice, analyzed the health records of 107 community-dwelling senior citizens treated at the Rutgers School of Dental Medicine clinic between 2015 to 2016.

The results showed that more than 25 percent of the patients had malnutrition or were at risk for malnutrition. The researchers saw a trend in which patients with 10 to 19 teeth were more likely to be at risk for malnutrition. Those patients classified as having malnutrition had higher rates of weight loss, ate less and more frequently reported that they suffered with dementia and/or depression and severe illnesses than those who had a normal nutrition status.

"The mouth is the entry way for food and fluid intake," said lead author Rena Zelig, director of the Master of Science in Clinical Nutrition Program at Rutgers School of Health Professions. "If its integrity is impaired, the functional ability of an individual to consume an adequate diet may be adversely impacted."

Although further studies need to examine the relationships between tooth loss and malnutrition risk, Zelig said the findings show that dental clinics are ideal locations to perform nutritional status screenings as they can identify patients who may not regularly visit a primary care provider and who may be at risk for malnutrition. "Clinicians also can provide patients with referrals to Registered Dietitians and community assistance programs such as Meals on Wheels to prevent further decline in nutritional status," she said.
This was the first part of a mixed-methods grant to research the associations between tooth loss and nutritional status in older adults. The second part of the grant built on these results and qualitatively studied the eating experience and eating-related quality of life of community-dwelling older adults using qualitative interviews.
The study sets the stage for further research to examine the relationships between tooth loss and malnutrition risk and the impact of tooth loss on the eating experience and eating-related quality of life.

Wednesday, October 24, 2018

Loss of first baby tooth a positive experience for children


Scared, ashamed, happy or proud - how do children feel when they lose their first baby tooth? An interdisciplinary research group at the University of Zurich has now found that children's feelings are predominantly positive. The study also reveals that previous visits to the dentist's as well as parental background and level of education affect how children experience the loss of their first tooth.

Deciduous teeth, more commonly known as milk or baby teeth, are the first set of teeth that develop in children. These teeth usually fall out and are replaced by permanent teeth. Children generally lose their first baby tooth when they're about six years old: The tooth comes loose and eventually falls out, leaving a gap which is then permanently filled by its replacement tooth. This gradual process is probably one of the first biological changes to their own bodies that children experience consciously. The emotions that accompany this milestone are extremely varied, ranging from joy at having finally joined the world of grown-ups to fear about the loss of a body part.

Parents report positive reactions

An interdisciplinary team of dental researchers and developmental and health psychologists at the University of Zurich, in cooperation with the City of Zurich's School Dental Services, has now examined the feelings that children experience when they lose their first baby tooth, and which factors are at play. The scientists surveyed parents of children who had already lost at least one of their milk teeth. Of the nearly 1,300 responses received for the study, around 80 percent of parents reported positive feelings, while only 20 percent told of negative emotions. Raphael Patcas, first author of the study, is happy with the findings: "The fact that four out of five children experience the loss of a baby tooth as something positive is reassuring, for parents and dentists alike."

The longer it's loose, the better the feelings

The researchers found that previous visits to dentists played a role when it comes to children's feelings. Children whose previous visits were cavity-related and thus perhaps associated with shame or guilt experienced fewer positive emotions when they later lost their first baby tooth. If, however, previous dental appointments were the result of an accident, and thus an abrupt, unexpected and painful event, then the loss of the first milk tooth was more likely to be associated with positive emotions. According to dental researcher Raphael Patcas, one possible explanation for this is that baby teeth loosen gradually before falling out - a process that, unlike an accident, unfolds slowly and predictably. This is also supported by the fact that children who experience the loosening of their tooth over an extended period of time tend to have more positive feelings: The longer the preparation and waiting time, the greater the relief and pride when the tooth finally falls out.

Parental education and background matter

Moreover, the study also found that sociodemographic factors are related to children's feelings: For example, children were more likely to have positive feelings such as pride or joy if the parents had a higher level of education and came from non-Western countries. The researchers indicate that cultural differences could be at play here: These include education style and norms that parents pass on to their children, as well as transitioning rituals that accompany the loss of the first baby tooth.
"Our findings suggest that children deliberately process previous experiences concerning their teeth and integrate them in their emotional development," says Moritz Daum, UZH professor of developmental psychology. This finding is important for dentists and parents alike: "Especially where cavities are concerned, it's worth communicating with children prudently", says Daum. "This way, emotions in connection with teeth and dentists can be put on the most positive trajectory possible."

New dental adhesive prevents tooth decay around orthodontic brackets




Researchers at Queen Mary University of London have produced a new orthodontic bracket bonding adhesive that protects the tooth surfaces around the brackets from decay. This decay is often referred to as white spot lesions which affects, according to a 2015 meta-analysis, nearly 70 per cent of people fitted with orthodontic braces*.

The problem areas are around the edges of the retaining brackets where plaque accumulates. Because of the wires and brackets it is difficult to keep the teeth clean. This results in many patients ending up with straight teeth after orthodontics but with blotchy marks that can affect their willingness to smile and reduce their self-confidence. This discolouration takes many months or even years to disappear.

The new bioactive bonding adhesive differs from the currently used materials by continuously releasing fluoride, calcium and phosphate to form fluorapatite. Fluorapatite will remineralise adjacent tooth surfaces and also reduce plaque formation around the orthodontic bracket, reducing the risk of initial decay seen as a chalky surface on the tooth enamel.

Professor Robert Hill at Queen Mary University of London said: “This is a significant breakthrough which will benefit all those wearing orthodontic braces” explained. The research we undertook is an extension of the technology we developed with BioMin Technologies when developing BioMin F toothpaste and this adhesive prevents the development of unsightly white spot lesions around the brackets.”

Braces are very popular, with more than 200,000 children and adults in England and Wales starting orthodontic treatment last year. They allow the wearer to have an attractive, confident smile, bite correctly, eat more comfortably, and to care for their teeth and gums more effectively. In the USA, over four million people are wearing braces, of which 25 percent are adults.

Professor Robert Hill added: “This new special adhesive includes a much lower sodium content than that used in BioMin F toothpastes so it reacts, rather than dissolves. Our latest research shows the adhesive forms protective fluorapatite - the fluoride analog of tooth mineral – around the brackets. We hope to see the first commercially available product within two years.”


The research is published in the journal Dental Materials.


Full bibliographic information

• Research paper: Fluoride containing bioactive glass composite for orthodontic adhesives — Apatite formation properties. N.A.Al-eesa, A.Johal, R.G.Hill, F.S.L.Wong. Dental Materials. Doi: 10.1016/j.dental.2018.04.009.


Monday, October 22, 2018

Poor oral health linked to higher blood pressure, worse blood pressure control



People with high blood pressure taking medication for their condition are more likely to benefit from the therapy if they have good oral health, according to new research in the American Heart Association's journal Hypertension

Findings of the analysis, based on a review of medical and dental exam records of more than 3,600 people with high blood pressure, reveal that those with healthier gums have lower blood pressure and responded better to blood pressure-lowering medications, compared with individuals who have gum disease, a condition known as periodontitis. Specifically, people with periodontal disease were 20 percent less likely to reach healthy blood pressure ranges, compared with patients in good oral health.

Considering the findings, the researchers say patients with periodontal disease may warrant closer blood pressure monitoring, while those diagnosed with hypertension, or persistently elevated blood pressure, might benefit from a referral to a dentist.

"Physicians should pay close attention to patients' oral health, particularly those receiving treatment for hypertension, and urge those with signs of periodontal disease to seek dental care," Pietropaoli said. "Likewise, dental health professionals should be aware that oral health is indispensable to overall physiological health, including cardiovascular status," said study lead investigator Davide Pietropaoli, D.D.S., Ph.D., of the University of L'Aquila in Italy.

The target blood pressure range for people with hypertension is less than 130/80 mmHg according to the latest recommendations from the American Heart Association/American College of Cardiology. In the study, patients with severe periodontitis had systolic pressure that was, on average, 3 mmHg higher than those with good oral health. Systolic pressure, the upper number in a blood pressure reading, indicates the pressure of blood against the walls of the arteries. 

While seemingly small, the 3mmHg difference is similar to the reduction in blood pressure that can be achieved by reducing salt intake by 6 grams per day (equal to a teaspoon of salt, or 2.4 grams of sodium), the researchers said.

The presence of periodontal disease widened the gap even farther, up to 7 mmHg, among people with untreated hypertension, the study found. Blood-pressure medication narrowed the gap, down to 3 mmHg, but did not completely eliminate it, suggesting that periodontal disease may interfere with the effectiveness of blood pressure therapy.

"Patients with high blood pressure and the clinicians who care for them should be aware that good oral health may be just as important in controlling the condition as are several lifestyle interventions known to help control blood pressure, such as a low-salt diet, regular exercise and weight control," Pietropaoli said.

While the study was not designed to clarify exactly how periodontal disease interferes with blood pressure treatment, the researchers say their results are consistent with previous research that links low-grade oral inflammation with blood vessel damage and cardiovascular risk.

Hypertension is estimated to affect up to 40 percent of people over age 25 worldwide.

Untreated or poorly controlled hypertension can lead to heart attacks, strokes and heart failure, as well as kidney disease. Hypertension is estimated to claim 7.5 million lives worldwide.

Red, swollen, tender gums or gums that bleed with brushing and flossing are tell-tale signs of inflammation and periodontal disease. So are teeth that look longer than before, a sign of receding gums, and teeth that are loose or separating from the gum line.

Wednesday, October 17, 2018

Researchers identify immune culprits linked to inflammation and bone loss in gum disease


Microbiome-triggered Th17 cells switch from protective to destructive; may be potential treatment targets
NIH/National Institute of Dental and Craniofacial Research
IMAGE
IMAGE: A new study led by NIDCR clinical investigator Dr. Niki Moutsopoulos suggests that periodontal disease is driven by Th17 immune cells, which are triggered by an unhealthy bacterial community. view more 
Credit: National Institute of Dental and Craniofacial Research, NIH
An unhealthy population of microbes in the mouth triggers specialized immune cells that inflame and destroy tissues, leading to the type of bone loss associated with a severe form of gum disease, according to a new study in mice and humans. The research, led by scientists from the National Institute of Dental and Craniofacial Research (NIDCR) at the National Institutes of Health and the University of Pennsylvania School of Dental Medicine, Philadelphia, could have implications for new treatment approaches for the condition. The findings appear online Oct. 17, 2018, in Science Translational Medicine.
Periodontal disease is a common disorder that affects nearly half of American adults over age 30, and 70 percent of adults 65 and older. In those affected, bacteria trigger inflammation of the tissues that surround the teeth, which can lead to loss of bone and teeth in an advanced stage of the disease called periodontitis.
"We've known for years that microbes stimulate inflammation. Removing bacteria by tooth-brushing and dental care controls inflammation, but not permanently, suggesting there are other factors at play," said study senior author Niki Moutsopoulos, D.D.S., Ph.D., a clinical investigator at NIDCR. "Our results suggest that immune cells known as T helper 17 cells are drivers of this process, providing the link between oral bacteria and inflammation."
Moutsopoulos and colleagues observed that T helper (Th) 17 cells were much more prevalent in the gum tissue of humans with periodontitis than in the gums of their healthy counterparts, and that the amount of Th17 cells correlated with disease severity.
Th17 cells normally live in so-called barrier sites--such as the mouth, skin, and digestive tract--where germs make first contact with the body. Th17 cells are known to protect against oral thrush, a fungal infection of the mouth, but they are also linked to inflammatory diseases such as psoriasis and colitis, suggesting that they play dual roles in health and disease.
To better understand this dynamic, the NIDCR scientists teamed up with an NIDCR-funded research group led by study senior author George Hajishengallis, D.D.S., Ph.D., at the University of Pennsylvania School of Dental Medicine and colleagues from NIH's National Institute of Allergy and Infectious Diseases (NIAID) and National Cancer Institute (NCI).
The scientists found that similar to humans, more Th17 cells accumulated in the gums of mice with periodontitis compared to healthy mice, which served as a control group.
To see if the oral microbiome might be the trigger for Th17 cell accumulation, the researchers placed mice on a broad-spectrum antibiotic cocktail. They found that eliminating oral microbes prevented expansion of Th17 cells in the gums of mice with periodontitis while leaving other immune cells unaffected, suggesting an unhealthy bacterial population triggers Th17 cell accumulation.
Next, the group wanted to know if blocking Th17 cells could lessen periodontal disease. When the scientists genetically engineered mice to lack Th17 cells, or gave the animals a small-molecule drug that prevents Th17 cell development, they saw similar outcomes: reduced bone loss from periodontitis. RNA analysis showed the Th17-blocking drug led to reduced expression of genes involved in inflammation, tissue destruction, and bone loss, suggesting that Th17 cells may mediate these processes in periodontitis.
Finally, the researchers studied a group of 35 patients at the NIH Clinical Center with a gene defect causing them to lack Th17 cells. The scientists reasoned that if Th17 cells are as important to periodontitis as the animal studies suggested, not having Th17 cells should protect against gum disease. This is indeed what the group found--the patients were less susceptible to the condition and had less inflammation and bone loss compared to age- and gender-matched volunteers.
"Our clinical observations point to the relevance of our animal studies to humans and provide further evidence that Th17 cells are drivers of periodontitis," said NIDCR researcher Nicolas Dutzan, Ph.D., first author of the paper.
"These results provide key insights into the mechanisms that underlie development of periodontal disease," said NIDCR Director Martha J. Somerman, D.D.S., Ph.D. "Importantly, they also offer compelling evidence for therapeutic targeting of specific cells, which might eventually help us provide better treatment and more relief to patients with this common disease."

Drivers of inflammation provide valuable targets for new gum disease therapies


T cells help fight off infection, but they can go overboard. A new study led by researchers at the University of Pennsylvania School of Dental Medicine and the National Institutes of Health (NIH) shows that a subset of T cells contributes to the problematic inflammation and bone loss that is associated with periodontitis, a severe form of gum disease.
The research, conducted with the help of animal models and a group of human patients with a rare genetic mutation, point to a new target for treating periodontitis, as well as other diseases involving the inappropriate response of this group of T cells, known as Th17 cells. These include autoimmune conditions such as rheumatoid arthritis and multiple sclerosis. The work appears in Science Translational Medicine.
"I think this work leaves no doubt that these cells are important mediators of periodontitis," says George Hajishengallis, the Thomas W. Evans Centennial Professor in the Department of Microbiology at Penn Dental Medicine. "The translational aspect of our studies is pinpointing a new approach to blocking the tissue destruction we see in periodontitis, by inhibiting Th17 development."
Hajishengallis collaborated on the work with Niki M. Moutsopoulos of the NIH's National Institute for Dental and Craniofacial Research, with whom he has made previous insights into the molecular drivers of periodontitis.
T cells are broadly considered to fall into two categories: helper T cells, which aid in orchestrating the immune system's response to threats, and cytotoxic T cells, which take a lead role in carrying out an attack. Until about 13 years ago, helper cells were further divided into two groups: Th1 or Th2 cells. Then a new subset, Th17 cells, was identified, and researchers quickly realized Th17 cells played a role in certain human diseases. By 2008, Hajishengallis and other researchers began to suspect that these cells may be implicated in periodontitis. More recent studies have found that people with chronic periodontitis have an unusually high number of Th17 cells in their gum tissue, but these investigations hadn't uncovered the particular role of these cells in the condition or whether they were required for the development of periodontitis.
In the current work, the researchers looked at gum tissue from patients with chronic periodontitis and confirmed that they had higher numbers of Th17 cells compared to healthy controls, with the numbers correlating with the severity of disease. In parallel, they observed that mice in which periodontitis was induced, Th17 cell numbers, along with the IL-17 signaling molecule which they produce, increased with the onset of gum disease. This increase in Th17 cell numbers, the researchers found, was the result of local proliferation rather than recruitment from nearby lymph nodes.
To interrogate possible triggers of the local expansion of Th17 cells, the team decided to see how changes in the community of microbes in the gum tissue, the gingival microbiome, affected the accumulation of Th17 cells. In the mouse model of disease, animals were treated with broad- or narrow-spectrum antibiotics. Only those antibiotics which lowered the numbers of Th17 cells were capable of suppressing the disease, again implicating these cells in disease.
To definitively link the cells to the condition, however, the researchers took advantage of a mouse model missing a key protein required for Th17 cell development, as well as a population of human patients with a mutation in the corresponding gene, Stat3, who are monitored at the NIH. In both cases, they found that the Stat3 mutation, which dramatically cut the number of Th17 cells present in the gum tissue, also protected against the bone loss seen in chronic periodontitis. While people with this Stat3 mutation have other problems, gum disease is not one of them.
"Here we have a unique patient population with the same defect we checked in the mice, and they are similarly not susceptible to the same disease," Hajishengallis says. "This type of rigorous evidence is not easy to come by in medical science."
Though antibiotics could serve to protect against the disease, the side effects of taking such drugs, which can kill both beneficial and disease-causing microbes throughout the body, are too significant to recommend the treatment for broad use. But employing a small-molecule that inhibits Th17 cell development gave the researchers a similar effect, reducing Th17 cell accumulation and associated periodontal bone loss in mice.
"There is no antibiotic that is that targeted, that specific," Hajishengallis says. Such an inhibitor offers promise as a periodontal therapy and perhaps as a target for treating other diseases in which Th17 play a destructive role.

Monday, October 15, 2018

Study suggests vaping does not stain teeth


IMAGE
IMAGE: Top row: The discoloration of enamel exposed to cigarette smoke. Middle row: Minimal discoloration of enamel exposed to the aerosol from a Tobacco Heating Product. Bottom row: Minimal discoloration of... view more 
Credit: British American Tobacco
A study by scientists at British American Tobacco has shown that e-cigarettes and tobacco heating products cause significantly less staining to teeth than conventional cigarettes.
For the first time at BAT, scientists assessed and compared a novel e-cigarette (EC), a tobacco heating product (THP) and a conventional cigarette for their impact on teeth enamel staining. The results are published today in the American Journal of Dentistry.
While cigarette smoke caused significant enamel discoloration, vapour from the EC and aerosol from the THP caused only minimal staining (see Figure 1).
These next generation products (NGPs) do not involve combustion; the vapour and aerosol they produce are less complex and contain significantly lower levels of certain toxicants compared to cigarette smoke.
It is well known that smoking cigarettes causes stains on teeth that cannot easily be removed by regular brushing, but little is known about such effects from NGPs. So scientists at BAT conducted in vitro teeth staining studies to compare the effect of an EC, BAT's THP glo, and a reference cigarette (3R4F).
Tests were carried out on enamel blocks cut from bovine incisors. To mimic conditions in the mouth, the enamel blocks were first incubated with saliva to allow the formation of a pellicle layer, a protective protein film that normally forms on teeth. The enamel blocks were exposed to the particulate matter (isolated from the smoke/vapour) for 14 days and then whole smoke/vapour (equivalent to one pack of cigarettes per day) for 5 days.
The enamel samples were assessed before, during and after treatment; colour readings were determined by an independent laboratory using an established method involving a commercially available spectrophotometer and trained scientists.
Discoloration of enamel blocks exposed to cigarette smoke was apparent in as little as one day and continued to increase as the concentration of cigarette smoke increased. In contrast, exposure to vapour from the EC or THP resulted in little or no colour change that was comparable to the untreated controls.
"Many studies have postulated that it is the tar in cigarette smoke that stains teeth. We now have a method where we can rapidly assess in the laboratory the level of enamel discoloration by cigarette smoke and vapour from our ECs and THPs," explains Annette Dalrymple, a senior scientist at BAT R&D.
"The data generated from this study clearly shows that the EC and THP assessed caused minimal discoloration--very promising for consumers of our NGPs. However, further studies are required to understand the long-term effect on teeth staining and oral health when smokers switch to using NGPs."

Friday, October 5, 2018

Periodontal disease bacteria may kick-start Alzheimer's



Long-term exposure to periodontal disease bacteria causes inflammation and degeneration of brain neurons in mice that is similar to the effects of Alzheimer's disease in humans, according to a new study from researchers at the University of Illinois at Chicago.
The findings, which are published in PLOS ONE, suggest that periodontal disease, a common but preventable gum infection, may be an initiator of Alzheimer's, which currently has no treatment or cure.
"Other studies have demonstrated a close association between periodontitis and cognitive impairment, but this is the first study to show that exposure to the periodontal bacteria results in the formation of senile plaques that accelerate the development of neuropathology found in Alzheimer's patients," said Dr. Keiko Watanabe, professor of periodontics at the UIC College of Dentistry and corresponding author on the study.
"This was a big surprise," Watanabe said. "We did not expect that the periodontal pathogen would have this much influence on the brain, or that the effects would so thoroughly resemble Alzheimer's disease."
To study the impact of the bacteria on brain health, the Watanabe and her colleagues -- including Dr. Vladimir Ilievski, UIC research assistant professor and co-author on the paper -- established chronic periodontitis, which is characterized by soft tissue damage and bone loss in the oral cavity, in 10 wild-type mice. Another 10 mice served as the control group. After 22 weeks of repeated oral application of the bacteria to the study group, the researchers studied the brain tissue of the mice and compared brain health.
The researchers found that the mice chronically exposed to the bacteria had significantly higher amounts of accumulated amyloid beta -- a senile plaque found in the brain tissue of Alzheimer's patients. The study group also had more brain inflammation and fewer intact neurons due to degeneration.
These findings were further supported by amyloid beta protein analysis, and RNA analysis that showed greater expression of genes associated with inflammation and degeneration in the study group. DNA from the periodontal bacteria was also found in the brain tissue of mice in the study group, and a bacterial protein was observed inside their neurons.
"Our data not only demonstrate the movement of bacteria from the mouth to the brain, but also that chronic infection leads to neural effects similar to Alzheimer's," Watanabe said.
The researchers say these findings are powerful in part because they used a wild-type mouse model; most model systems used to study Alzheimer's rely on transgenic mice, which have been genetically altered to more strongly express genes associated with the senile plaque and enable Alzheimer's development.
"Using a wild-type mouse model added strength to our study because these mice were not primed to develop the disease, and use of this model gives additional weight to our findings that periodontal bacteria may kick-start the development of the Alzheimer's," Watanabe said.
The researchers say that understanding causality and risk factors for the development of Alzheimer's is critical to the development of treatments, particularly when it comes to sporadic, or late-onset disease, which constitutes more than 95 percent of cases and has largely unknown causes and mechanisms.
While the findings are significant for the scientific community, Watanabe said there are lessons for everyone.
"Oral hygiene is an important predictor of disease, including diseases that happen outside the mouth," she said. "People can do so much for their personal health by taking oral health seriously."

Wednesday, October 3, 2018

Young children's oral bacteria may predict obesity




The composition of oral microbiota -- the collection of microorganisms, including beneficial bacteria, residing in the mouth -- in two-year-old children may predict their weight gain, according to a new study of over 226 children and their mothers.
Credit: Penn State
Weight gain trajectories in early childhood are related to the composition of oral bacteria of two-year-old children, suggesting that this understudied aspect of a child's microbiota -- the collection of microorganisms, including beneficial bacteria, residing in the mouth -- could serve as an early indicator for childhood obesity. A study describing the results appears September 19 in the journal Scientific Reports.
"One in three children in the United States is overweight or obese," said Kateryna Makova, Pentz Professor of Biology and senior author of the paper. "If we can find early indicators of obesity in young children, we can help parents and physicians take preventive measures."
The study is part of a larger project with researchers and clinicians at the Penn State Milton S. Hershey Medical Center called INSIGHT, led by Ian Paul, professor of pediatrics at the Medical Center, and Leann Birch, professor of foods and nutrition at the University of Georgia. The INSIGHT trial includes nearly 300 children and tests whether a responsive parenting intervention during a child's early life can prevent the development of obesity. It is also designed to identify biological and social risk factors for obesity.
"In this study, we show that a child's oral microbiota at two years of age is related to their weight gain over their first two years after birth," said Makova.
The human digestive tract is filled with a diverse array of microorganisms, including beneficial bacteria, that help ensure proper digestion and support the immune system. This "microbiota" shifts as a person's diet changes and can vary greatly among individuals. Variation in gut microbiota has been linked to obesity in some adults and adolescents, but the potential relationship between oral microbiota and weight gain in children had not been explored prior to this study.
"The oral microbiota is usually studied in relation to periodontal disease, and periodontal disease has in some cases been linked to obesity," said Sarah Craig, a postdoctoral scholar in biology at Penn State and first author of the paper. "Here, we explored any potential direct associations between the oral microbiota and child weight gain. Rather than simply noting whether a child was overweight at the age of two, we used growth curves from their first two years after birth, which provides a more complete picture of how the child is growing. This approach is highly innovative for a study of this kind, and gives greater statistical power to detect relationships."
Among 226 children from central Pennsylvania, the oral microbiota of those with rapid infant weight gain -- a strong risk factor for childhood obesity -- was less diverse, meaning it contained fewer groups of bacteria. These children also had a higher ratio of Firmicutes to Bacteroidetes, two of the most common bacteria groups found in the human microbiota.
"A healthy person usually has a lot of different bacteria within their gut microbiota," said Craig. "This high diversity helps protect against inflammation or harmful bacteria and is important for the stability of digestion in the face of changes to diet or environment. There's also a certain balance of these two common bacteria groups, Firmicutes and Bacteroidetes, that tends to work best under normal healthy conditions, and disruptions to that balance could lead to dysregulation in digestion."
Lower diversity and higher Firmicutes to Bacteroidetes (F:B) ratio in gut microbiota are sometimes observed as a characteristic of adults and adolescents with obesity. However, the researchers did not see a relationship of weight gain with either of these measures in gut microbiota of two-year-olds, suggesting that the gut microbiota may not be completely established at two years of age and may still be undergoing many changes.
"There are usually dramatic changes to an individual's microbiota as they develop during early childhood," said Makova. "Our results suggest that signatures of obesity may be established earlier in oral microbiota than in gut microbiota. If we can confirm this in other groups of children outside of Pennsylvania, we may be able to develop a test of oral microbiota that could be used in clinical care to identify children who are at risk for developing obesity. This is particularly exciting because oral samples are easier to obtain than those from the gut, which require fecal samples."
Interestingly, weight gain in children was also related to diversity of their mother's oral microbiota. This could reflect a genetic predisposition of the mother and child to having a similar microbiota, or the mother and child having a similar diet and environment.
"It could be a simple explanation like a shared diet or genetics, but it might also be related to obesity," said Makova. "We don't know for sure yet, but if there is an oral microbiome signature linked to the dynamics of weight gain in early childhood, there is a particular urgency to understand it. Now we are using additional techniques to look at specific species of bacteria -- rather than larger taxonomic groups of bacteria -- in both the mothers and children to see whether specific bacteria species influence weight gain and the risk of obesity."