論文

内容

要旨

Association of number of teeth present withnutrient intake and food group consumption（現在歯数と栄養素摂取および食品群別摂取量との関連）

主指導教員：内藤（医系科学研究科真理子教授
口腔保健疫学）

副指導教員：太田（医系科学研究科公衆口腔保健学）

副指導教員：竹本（医系科学研究科淺枝
（医歯薬保健学研究科耕司教授
俊伸教授

口腔保健管理学）

麻夢可口腔健康科学専攻）

Introduction
Tooth loss reduces masticatory ability, which can limit the variety of foods a person eats and,in turn can affect nutrient intake and nutritional status. Although numerous studies havereported on teeth and nutrient intake, the dental care system and food culture have changed
dramatically over time, leading to changes in the relationship between teeth and nutrient
intake. Dietary habits are influenced by a number of factors, including age, gender andnational food culture. Most previous studies have been conducted with older people, with few
reports on middle-aged people.
This cross-sectional study aimed to clarify the associations between tooth loss, and nutrient
intake and food consumption in a population of middle-aged Japanese adults.
Materials and methods
For the current study, the data were derived from the baseline survey of the J-MICC Studyin the Shizuoka and Daiko areas. Inclusion criteria for the Shizuoka study were residents ofthe west-central area of Shizuoka Prefecture, Japan, and individuals who presented for
health examinations at the Seirei Preventive Health Care Center in Hamamatsu City,
Shizuoka Prefecture, Japan, between January 2006 and December 2007. Participants in theDaiko study were recruited primarily through a citywide mailbox distribution of flyers,
personal communications, and community information (e.g., posters in public or commercialfacilities) and visited the Daiko Medical Center of Nagoya University in Nagoya, Japan.
Subjects completed a self-administered questionnaire on the number of teeth, medical
history (diabetes, cancer, heart disease, and stroke), educational background, employment,and lifestyle factors such as diet, smoking, and exercise habits. The subjects were divided
into four groups according to the number of teeth present: 0, 1-19, 20-27, and 28-32 teeth.
The background characteristics of the subjects were analyzed using the Kruskal-Wallis test
for continuous variables and the Chi-square test for categorical data. We calculated nutrient
intake and food group consumption per 1000 kcal of total energy intake.
Subjects with missing covariate data were excluded. All data analyses were performed withIBM SPSS Statistics for Windows version 28 (IBM Japan, Ltd, Tokyo, Japan).
Results
The number of participants was 5,005 in the Shizuoka area and 5,152 in the Daiko area, fora total of 10,157. Of these, we excluded 119 participants based on any of the following
conditions: (i) lack of data on the number of teeth present; and (ⅱ) declared that the numberof teeth is 33 or more. In the end, 10,038 subjects remained for analysis. The age distributionof the subjects peaked at 50 to 59 years (32.8%), with a mean age ± SD of 52.4 ± 9.6 years,
and 52.2% of the subjects were female.

In both genders, those with 20-27 teeth were the highest, and edentulous subjects were theleast. Mean age decreased with increasing number of remaining teeth. Current smokers andthose with a high school education or less were more common among those with fewer teeth,
while those who were employed were more common among those with remaining teeth.
Cholesterol intake was negatively associated with the number of teeth only in women(p=0.026). No significant difference was found in men, but a similar trend was observed. The
consumption of confectioneries and eggs was also negatively associated with the number ofteeth only in women (p=0.017,0.020). The consumption of breads, however, was higher inthose with more remaining teeth (p=0.025).
Discussion
In the present study, among adult women, the number of teeth present was positively
associatedwithbreads

consumption

andnegatively

associatedwithcholesterol,confectioneries, and eggs.
Regarding the number of teeth and breads consumption, edentulous individuals reported
eating breads less frequently than those with natural teeth. On the other hand, those whoreported the impact of dental and oral health on their ability to eat (those who reported
difficulty eating due to oral health) reported more difficulty eating most of the foods studied
than those who did not report this, with the exception of sliced and crusted bread.
The association between the number of teeth and cholesterol intake was similar to previousstudies (Papas et al. 1998, Sahyoun et al. 2003, Hung et al, 2005). Cholesterol intake
increased as the number of teeth decreased.
In the present study, there was also a significant association with egg consumption. Eggs
are soft and easy to chew both before and after cooking, so it is assumed that they are
preferred by people with few teeth, but there are few reports on the relationship between thenumber of teeth and eggs.
Wakai et al. (2010) reported that mean intakes of confectioneries were increased among
those with fewer teeth. Furthermore, Yoshida et al. (2011) reported that the lost contact groupreported significantly higher consumption of confectionaries (foods rich in sugar) than did
the retained contact group. Both are similar to the present findings. It is predicted that theconsumption of easy-to-chew confectioneries increased as the number of teeth decreased, but
it is also possible that the high consumption of confectioneries led to an increased risk ofdental caries and a decrease in the number of teeth.
Conclusions
The results suggest that the number of teeth present is independently associated with poor
nutrition in Japanese adult women.