title: Dietary glycemic index and glycemic load in relation to HbA1c in Japanese obese adults: a cross-sectional analysis of the Saku Control Obesity Program.
abstract: BACKGROUND
  Dietary glycemic index or load is thought to play an important role in glucose metabolism. However, few studies have investigated the relation between glycemic index (GI) or load (GL) and glycemia in Asian populations. In this cross-sectional analysis of a randomized controlled trial, the Saku Control Obesity Program, we examined the relation between the baseline GI or GL and glycemia (HbA1c and fasting plasma glucose [FPG] levels), insulin resistance (HOMA-IR), β-cell function (HOMA-β), and other metabolic risk factors (lipid levels, diastolic and systolic blood pressure, and adiposity measures).
  
  
  METHODS
  The participants were 227 obese Japanese women and men. We used multiple linear regression models and logistic regression models to adjust for potential confounding factors such as age, sex, visceral fat area, total energy intake, and physical activity levels.
  
  
  RESULTS
  After adjustments for potential confounding factors, GI was not associated with HbA1c, but GL was positively associated with HbA1c. For increasing quartiles of GI, the adjusted mean HbA1c were 6.3%, 6.7%, 6.4%, and 6.4% (P for trend = 0.991). For increasing quartiles of GL, the adjusted mean HbA1c were 6.2%, 6.2%, 6.6%, and 6.5% (P for trend = 0.044). In addition, among participants with HbA1c ≥ 7.0%, 20 out of 28 (71%) had a high GL (≥ median); the adjusted odds ratio for HbA1c ≥ 7.0% among participants with higher GL was 3.1 (95% confidence interval [CI] = 1.2 to 8.1) compared to the participants with a lower GL (<median). Further, among 16 participants with FPG ≥ 150 mg/dL, 13 participants (81.3%) had a higher GL; the adjusted odds ratio for FPG ≥ 150 mg/dL among participants with a higher GL was 8.5 (95% confidence interval = 1.7 to 43.4) compared to those with a lower GL. In contrast, GI and GL were not associated with metabolic risk factors other than glycemia.
  
  
  CONCLUSIONS
  Our findings suggest that participants with poor glycemic control tend to have a higher GL in an obese Japanese population.
authors.affiliation: Department of Diabetes Research, Diabetes Research Center, National Center for Global Health and Medicine, Tokyo, Japan. mnoda@hosp.ncgm.go.jp.
authors.forename: Maki
authors.initials: M
authors.lastname: Goto
authors.forename: Akemi
authors.initials: A
authors.lastname: Morita
authors.forename: Atsushi
authors.initials: A
authors.lastname: Goto
authors.forename: Satoshi
authors.initials: S
authors.lastname: Sasaki
authors.forename: Naomi
authors.initials: N
authors.lastname: Aiba
authors.forename: Takuro
authors.initials: T
authors.lastname: Shimbo
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Terauchi
authors.forename: Motohiko
authors.initials: M
authors.lastname: Miyachi
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Noda
authors.forename: Shaw
authors.initials: S
authors.lastname: Watanabe