Dietary glycemic index and glycemic load in relation to risk of overweight in Japanese children and adolescents: the Ryukyus Child Health Study

Abstract

Objective: Epidemiologic evidence concerning the role of dietary glycemic index (GI) and glycemic load (GL) in obesity during childhood and adolescence is limited, particularly in non-Western populations. We examined the association between dietary GI and GL as well as dietary fiber intake and overweight status in Japanese children and adolescents. Subjects: This Japanese cross-sectional study included 15 974 children (6-11 years; 7956 boys and 8018 girls) and 8202 adolescents (12-15 years; 3944 boys and 4258 girls). Methods: Dietary intake was assessed using a self-administered diet history questionnaire for children and adolescents. Body mass index (BMI) was calculated from self-reported body weight and height. Overweight was defined according to the International Obesity Task Force age-and sex-specific BMI cutoffs, which correspond to an adult BMI of X25 kg m -2 . Results: The overall prevalence of overweight was 13.2%. Mean (s.d.) dietary GI was 63.0 (3.1), mean dietary GL was 85.0 (12.4) per 4184 kJ (1000 kcal) and mean dietary fiber intake was 5.9 (1.2) g/4184 kJ. After adjustment for potential confounding factors, dietary GL was positively associated with the risk of overweight in male children, female children and male adolescents (P for trend o0.0001, o0.0001 and 0.006, respectively), but not in female adolescents. No such independent associations were observed for dietary GI or fiber intake. Conclusion: This large cross-sectional study in Japan suggests that higher dietary GL is associated with increasing risk of overweight in male and female children and male adolescents, but not female adolescents.

Self-Reported Rate of Eating and Risk of Overweight in Japanese Children: Ryukyus Child Health Study

“…The mechanism linking a higher rate of eating and overweight has been speculated to involve increasing energy intake; hence, we did not adjust for energy intake in our analysis. In the present study, underreporting of energy intake, assessed based on the ratio of reported energy intake to estimated energy requirement, was prevalent, particularly in overweight subjects (15). Nonetheless, a higher rate of eating was associated with not only an increased risk of overweight but also a higher energy intake.…”

“…Of the 38,212 eligible students, 28,885 (75.6% of the eligible sample) participated in RYUCHS. Excluded from the present analysis were 3,581 students with incomplete data on the variables under study, and 1,128 who reported extremely low or high energy intake (Ͻ625-1,225 or Ͼ2,475-4,650 kcal/d, depending on age and sex) (15,16). The fi nal sample thus consisted of 24,176 students (63.3% of the eligible sample).…”

“…RYUCHS was a school-based, cross-sectional, self-administered questionnaire survey conducted in Naha City and Nago City, Okinawa, Japan, between September 2004 and January 2005 (15). All public elementary and junior high schools in Naha City (nϭ35 and 17, respectively) and Nago City (nϭ17 and 8, respectively) participated in RYUCHS.…”

“…Multivariate adjusted ORs were calculated by adjusting for potential confounding factors, including age (y, continuous), paternal educational level (junior high school; high school; junior college or vocational technical school; or university), maternal educational level (junior high school; high school; junior college or vocational technical school; or university), municipality (Naha City or Nago City), television or computer game use (Ͻ2 h/d, 2-3 h/d, or Ͼ3 h/d), habitual exercise (none, Յ2 times/wk, 3-4 times/wk, or Ն5 times/wk), protein intake (% of energy, continuous), fat intake (% of energy, continuous), and dietary fi ber intake (g/1,000 kcal, continuous). We did not conduct adjustment for dietary glycemic load, a variable signifi cantly associated with the prevalence of overweight in this population, because of extremely high correlation between dietary fat intake and glycemic load (Pearson correlation coeffi cient: ϾϪ0.93) (15). Trends of association were assessed by a logistic regression model which assigned consecutive integers to the levels of the independent variable.…”

Effects of the National School Lunch Program on Bone Growth in Japanese Elementary School Children

“…We excluded 16 subjects who reported extremely low or high energy intake (i.e., ,0.5 times the estimated energy requirement value for the lowest physical activity category or .1.5 times that for the highest physical activity category, according to the dietary reference intakes for Japanese issued in 2015). The exclusion criteria used in the study of Murakami et al (8) were applied in the present study.…”