Tooth decay more widespread among obese and underweight, huge Israeli study finds
Researchers say study based on 66,790 soldiers should prompt vigilance, shape policy; low or high BMI can be tied to socioeconomic status, which may also impact dental health
Nathan Jeffay is The Times of Israel's health and science correspondent
Obese and underweight people have significantly more decayed teeth than the rest of the population, according to a first-of-its kind Israeli study.
Among a huge sample, those who were of normal weight or were overweight averaged 2 or 2.1 decayed teeth respectively. But among both the obese and underweight demographics, the average was 2.4 decayed teeth — or in dentists’ jargon, teeth with caries.
The newly published peer-reviewed research analyzed dental records along with a mass of other data for 66,790 Israeli soldiers, with an average age of 22.8.
It used standard categorizations of people according to body mass index (BMI): a score of under 18.5 is underweight; 18.5 to 25 is normal; 25 to 30 is overweight, and over 30 is obese. The use of BMI as a measure has been questioned by some researchers who say it doesn’t take into account factors such as muscle mass.
“This research demonstrates a positive association between underweight and obesity BMI categories and dental caries,” Dr. Galit Almoznino of Hebrew University’s Department of Oral Medicine and Hadassah Medical Center wrote together with her colleagues.
The scholars don’t offer a hypothesis for why there is a correlation, but they do identify practical implications for their findings. Almoznino told The Times of Israel that people who are underweight and obese should be extra vigilant about dental health, and policymakers should put extra focus on their dental needs.
She said: “The findings highlight the need to raise awareness for these common morbidities and their association, and they highlight the need to better allocate resource distribution to focus on underweight and obese populations who require dental treatment.”
The question of a correlation between BMI and caries has, until now, been undetermined. Almoznino and her colleagues claimed their research represents the first study to perform detailed analyses that cross-referenced dental caries with BMI categories using “novel approaches” for statistics and analysis.
They believe Israel is particularly well placed for such research, because of the meticulous record keeping in the military, and also because the ethnic diversity means the study is likely to be generalizable to many countries.
“As Israel is an immigrant country, the study included a variety of ethnic groups, allowing for reference with other populations,” the authors stated.
They discussed the possibility that being underweight or obese was just a byproduct of other factors that are common among those with high levels of caries, like socioeconomic status.
In fact, a range of characteristics often correlate with a high level of caries. These include low socioeconomic status, low education levels, unhealthy lifestyle habits such as smoking, inadequate toothbrushing, and sugary foods, as well as health conditions such as metabolic syndromes.
However, the sample was large enough to perform a detailed analysis that looked at the incidence of caries within each demographic. For example, it compared irregular tooth-brushers of different BMIs, people of low socioeconomic status with different BMIs, and so on.
The authors reported that the strong correlation between BMI and caries remained. As such, the conclusion holds “independent of the socio-demographic, health-related practices, and other systemic conditions related to metabolic syndromes that were studied.”