Chewing Status and Life Expectancy in Prefectures: Ecological Study Using National Database

Abstract

 This study was conducted to clarify whether the chewing status is associated with life expectancy in prefectural populations of Japan, with a focus on the involvement of lifestyle factors.

 Based on distributions of prefecture-, sex-, and age-specific items obtained from the 8th National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB Open Data for 2020), proportions of individuals with chewing difficulty, drug use, poor lifestyle habits, and obesity were calculated, with age-adjustment performed using the direct method. The questionnaire answers: “Sometimes it is difficult to chew due to dental problems” and “I can hardly chew”, were considered to indicate chewing difficulty. Pearson’s correlation coefficient (r) was used to analyze the relationship between the proportion of individuals with chewing difficulty and life expectancy, as well as the proportion of each item noted; then, multiple linear regression analysis was conducted with life expectancy as the dependent variable and items significantly correlated with life expectancy as explanatory variables, and standardized regression coefficient (β) values were calculated.

 The proportion of both males and females with chewing difficulty showed a significant negative correlation with life expectancy (males: r=-0.501, p<0.001; females: r=-0.442, p=0.002), while it was significantly positively correlated in both sexes with antihypertensive drug use, hypoglycemic drug use, current smoking habit, and obesity. Variables associated with life expectancy for males were chewing difficulty (β=-0.241), antihypertensive drug use (β=-0.348), and alcohol consumption (β=-0.429); those for females were current smoking habit (β=-0.317), eating fast (β=0.347), and obesity (β=-0.388).

 Life expectancy tended to be lower for both males and females in prefectures with a higher proportion of individuals exhibiting chewing difficulty. Independent of lifestyle factors, there was a negative association of chewing difficulty with life expectancy in males, but not females.