The prevalence of poor glycemic control was 5.9% (Table 1). Respondents with poor glycemic control were significantly more likely to be male (p < 0.001), be older (p < 0.001), have a higher body mass index (BMI; p < 0.001), be a current smoker (p < 0.001), exercise regularly (p < 0.001), eat quickly (p < 0.001), and have a low ability to chew well (p < 0.001).
Table 2 shows the results of univariate logistic regression analysis with poor glycemic control as the dependent variable in all participants. The results showed that the odds ratio (OR) for poor glycemic control was higher among those who were male (OR, 3.104; 95% confidence interval [CI], 2.782 to 3.462), were older (OR, 1.081; 95% CI, 1.076 to 1.087), had a higher BMI (OR, 1.224; 95% CI, 1.211 to 1.237), had regular exercise habits (OR, 1.275; 95% CI, 1.149 to 1.414), and ate quickly (OR, 1.307; 95% CI, 1.190 to 1.435) than among those who did not. The results also showed that the OR for poor glycemic control was lower among those who had the ability to chew well (OR, 0.615; 95% CI, 0.545 to 0.693) than among those who did not.
Table 3 shows the results of the multivariate adjusted logistic regression analysis with poor glycemic control as the dependent variable in all participants. Poor glycemic control was significantly associated with male gender (OR, 2.843; 95% CI, 2.534 to 3.189), older age (OR, 1.087; 95% CI, 1.081 to 1.093), current smoker status (OR, 1.374; 95% CI, 1.224 to 1.541), the presence of regular exercise habits (OR, 0.855; 95% CI, 0.766 to 0.955), the ability to chew well (OR, 0.810; 95% CI, 0.715 to 0.918), and a fast eating speed (OR, 1.338; 95% CI, 1.214 to 1.552) after adjusting for gender, age, smoking status, regular exercise habits, eating speed, and chewing status. After additional adjustments for the BMI, poor glycemic control was significantly associated with male gender (OR, 2.142; 95% CI, 1.903 to 2.411), older age (OR, 1.093; 95% CI, 1.087 to 1.099), higher BMI (OR, 1.234; 95% CI, 1.219 to 1.249), current smoker status (OR, 1.378; 95% CI, 1.223 to 1.552), and the ability to chew well (OR, 0.795; 95% CI, 0.699 to 0.904).
The numbers of participants with poor glycemic control were 31 (1.0%) in the 20-to-39-year-old group, 1,498 (5.6%) in the 40-to-64-year-old group, 362 (14.9%) in the ≥ 65-year-old group, and 1,891 (5.9%) in total among all participants (Table 4). The numbers of participants who reported having the ability to chew well were 2,826 (90.8%) in the 20-to-39-year-old group, 23,145 (87.1%) in the 40-to-64-year-old group, 1,974 (81.0%) in the ≥ 65-year-old group, and 27,945 (87.0%) in total among all participants. There were significant differences in the prevalence of poor glycemic control and chewing well among the different age groups (p < 0.001).
Table 5 shows the results of the multivariate adjusted logistic regression analysis with poor glycemic control as the dependent variable in different age groups. In the 20-to-39-year-old group, poor glycemic control was significantly associated with older age (OR, 1.208; 95% CI, 1.051 to 1.389) and higher BMI (OR, 1.319; 95% CI, 1.238 to 1.406) after adjusting for gender, age, smoking status, regular exercise habits, eating speed, and chewing status. In the 40-to-64-year-old group, poor glycemic control was significantly associated with male gender (OR, 2.304; 95% CI, 2.009 to 2.643), older age (OR, 1.102; 95% CI, 1.093 to 1.112), higher BMI (OR, 1.241; 95% CI, 1.225 to 1.257), current smoker status (OR, 1.369; 95% CI, 1.204 to 1.557), and the ability to chew well (OR, 0.848; 95% CI, 0.732 to 0.983). Furthermore, in the ≥ 65-year-old group, poor glycemic control was also significantly associated with male gender (OR, 1.593; 95% CI, 1.246 to 2.036), older age (OR, 1.058; 95% CI, 1.018 to 1.100), higher BMI (OR, 1.156; 95% CI, 1.117 to 1.197), and the ability to chew well (OR, 0.655; 95% CI, 0.499 to 0.859).