TABLE 5.
Characteristics of studies included in the meta-analysis of the association of glycemic index and glycemic load with T2D1
| Study (reference) | Country | Sex | Baseline age2 | Comorbidities excluded at baseline | No. of T2D cases | Follow-up | Diet assessment | T2D assessment | Confounders | NOS |
| y | y | |||||||||
| Hodge et al (32)3 | Australia | M, F | 54.5 | Diabetes, angina, heart attack | 365 | 4 | 121-item FFQ | Self-report + confirmation from doctor | Age, sex, country of birth, physical activity, family history of diabetes, alcohol intake, educational level, weight change in the past 5 y, energy intake, BMI, and WHR | 7 |
| Hopping et al (44) | USA | M, F | 45–75 | Diabetes | 8587 | 14 | FFQ | Self-report + confirmation by health plan | BMI, physical activity, education, calories | 7 |
| Krishnan et al (35) | USA | F | 21–69 | Diabetes, gestational diabetes, cancer, cardiovascular disease | 1938 | 8 | 68-item FFQ | Self-report of physician-diagnosed diabetes | Age, BMI, energy intake, family history of diabetes, physical activity, cigarette use, cereal fiber intake, protein intake, fat intake | 6 |
| Meyer et al (36) | USA | F | 55–69 | Diabetes | 1141 | 6 | 127-item FFQ | Self-report | Age, total energy intake, BMI, WHR, education, pack-years of smoking, alcohol intake, physical activity, total dietary fiber | 6 |
| Mosdøl et al (37) | UK | M, F | 39–63 | Diabetes | 329 | 9–13 | 127-item FFQ | Self-report of doctor's diagnosis, diabetic medication use, and 2-h oral-glucose-tolerance test | Sex, age group, ratio of energy intake to energy expenditure, employment grade, physical activity, smoking, baseline BMI and WHR, intakes of alcohol, fiber, and carbohydrates | 8 |
| Patel et al (45)4 | USA | M, F | 50–74 | Diabetes, cancer | NR | 9 | 68-item FFQ | Self-report | Age, sex, race, history of gallstones, smoking, family history of pancreatic cancer, total energy intake, location of weight gain, sedentary behavior, BMI | 6 |
| Rossi et al (38) | Greece | M, F | 50.4 | Diabetes, cancer, cardiovascular disease, stroke | 2330 | 11.345 | 150-item FFQ | Medical records, discharge diagnosis, or death certificate | Age, sex, educational level, BMI, physical activity, WHR, total noncarbohydrate energy intake | 8 |
| Sahyoun et al (39) | USA | M, F | 70–79 | Diabetes | 99 | 4 | 108-item FFQ | Annual report of physician diagnosis, reported use of exogenous insulin or oral hypoglycemic medication use, or fasting serum glucose ≥126 mg/dL | Age, sex, race, clinical site, education, physical activity, baseline fasting glucose, BMI, alcohol consumption, and smoking status | 8 |
| Sakurai et al (40) | Japan | M | 46 | 133 | 6 | 147-item FFQ | Fasting plasma glucose ≥126 mg/dL, 2-h glucose ≥200 mg/dL in a 75-g oral-glucose-tolerance test, or treatment with insulin or an oral hypoglycemic agent | Age, BMI, family history of diabetes, smoking, alcohol intake, habitual exercise, presence of hypertension and hyperlipidemia at baseline, total energy, total fiber | 8 | |
| Similä et al (41) | Finland | M | 50–69 | Diabetes | 1098 | 12 | 276-item FFQ | Registry of reimbursement for medication use | Age, intervention group, BMI, smoking, physical activity, intakes of total energy and alcohol, energy-adjusted intakes of fat, fiber, and coffee | 8 |
| Sluijs et al (10) | Europe | M, F | 35–70 | Diabetes | 11,559 | 125 | FFQ | Self-report, linkage to primary care registers, secondary care registers, medication use, and hospital admissions and mortality data | Center, age, sex, educational level, physical activity, BMI, menopausal status, smoking status, alcohol consumption, energy intake, dietary protein, P:S, fiber (all energy-adjusted) | 9 |
| Stevens et al (31)6 | USA | M, F | 45–64 | Diabetes | 14487 | 95 | 66-item FFQ | Fasting glucose ≥126 mg/dL, or nonfasting glucose ≥200 mg/dL, physician report of diabetes, or reported taking diabetes medication within 2 wk preceding their examination | Age, BMI, sex, field center, educational level, smoking status, physical activity, cereal fiber (glycemic index and glycemic load were energy-adjusted) | 8 |
| van Woudenbergh et al (42) | Netherlands | M, F | 67.38 | Diabetes | 456 | 12.45 | 170-item FFQ | Confirmation from general practitioner and 1) plasma glucose ≥7.0 mmol/L, 2) random plasma glucose ≥11.1 mmol/L, 3) antidiabetes medication use, or 4) treatment by diet | Age, sex, smoking, family history of diabetes, BMI, C-reactive protein, and intakes of energy, protein, saturated fat, alcohol, and fiber | 8 |
| Villegas et al (43) | China | F | 40–70 | Diabetes, cardiovascular disease, cancer | 1605 | 5 | 77-item FFQ | Self-report of T2D and at least one of the American Diabetes Association criteria | Age, energy, BMI, WHR, smoking status, alcohol, physical activity, income, educational level, occupation, diagnosis of hypertension | 8 |
FFQ, food-frequency questionnaire; NOS, Newcastle-Ottawa scale; NR, not reported; P:S, PUFA to SFA ratio; T2D, type 2 diabetes; WHR, waist-to-hip ratio.
Values are means or ranges at baseline.
The study by Hodge et al (32) was included in the sensitivity meta-analysis of glycemic index and T2D. Risk estimates for the 10-unit difference in glycemic index were approximated to represent the difference between the highest and lowest quartiles. Risk estimates for the association of highest compared with lowest glycemic load quartiles and T2D were obtained from online supplemental material of Livesey et al (9), who obtained these estimates by direct e-mail correspondence from the author.
Confounders reported in the table are for associations between glycemic load and pancreatic cancer risk. Results for T2D are presented in the text.
Median follow-up time.
The study by Stevens et al was included in the sensitivity meta-analysis on the association of glycemic index and T2D. Risk estimates for the highest and lowest quartile were computed from continuous measures by first calculating the unit difference in median glycemic index in extreme quartiles. Risk estimates were then scaled accordingly.
Calculated on the basis of incidence of diabetes in African American and white adults.
Calculated from Table 1 in van Woudenbergh et al (42) as the weighted average of age in tertiles of glycemic index.