TABLE 1.
General characteristics of the prospective cohort studies included in the meta‐analysis of whole grain intake and risk of type 2 diabetes
| First Author. Year | Country | Age (range) | Sample size | Follow‐up duration (years) | Cohort name | Cases | Exposure | Dietary assessment | Comparison | HR (95% CI) (high versus low category) | Adjustments a | NOS |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Meyer et al. (2000) | United States | 55–69 | F:35,988 | 6 | IWHS | 1141 | WG | Baseline FFQ | Q5 versus Q1 | 0.79 (0.65, 0.96) | 1, 4, 5, 6, 8, 17, 22, 25 | 7 |
| Montonen et al. (2003) | Finland | 40–69 | M/F:4316 | 10 | FMC | 156 | WG | Baseline FFQ | Q4 versus Q1 | 0.65 (0.36, 1.18) | 1, 2, 4, 5, 24, 25, 32 | 8 |
| Van Dam et al. (2006) | United States | 21–69 | F:41,186 | 8 | BWHS | 1964 | WG | Repeated FFQ | C4 versus C1 | 0.82 (0.71–0.94) | 1, 4, 5, 6, 11, 14, 17, 25, 26, 29, 30, 31 | 7 |
| Fisher et al. (2009) | Germany | 35–65 | M/F:2318 | 7 | EPIC‐Postdom | 724 | WG | Baseline FFQ | per 50g/day portion | CC genotype: 0.86 (0.75, 0.99) CT+TT genotype: 1.08 (0.96, 1.23) | 1, 2, 4, 5, 6, 10, 17, 21, 23, 26, 28, 29,31 | 5 |
| Wirström et al. (2013) | Sweden | 35–56 | F/M:4941 | 8–10 | – | 165 | WG | Repeated FFQ | C3 versus C1 | 0.71(0.48,1.04) | 1, 2, 4, 5, 9, 14, 17, 20 | 6 |
| Parker et al. (2013) | United States | 50–79 | F:72,215 | 7.9 | WHI | 3465 | WG | Repeated FFQ | C6 versus C1 | 0.75 (0.63, 0.89) | 1, 3, 4, 5, 6, 8, 14, 15, 17, 19, 25 | 6 |
| Ericson et al. (2018) | Sweden | 45–74 | M/F: 25,069 | 17 | MDC | 3588 | WG | Baseline FFQ | T3 versus T1 | 0.89 (0.82–0.96) | 1, 2, 4, 5, 6, 9,17, 18, 25, 27 | 8 |
| Kyrø et al. (2018) | Denmark | 50–65 | M/F: 55,465 | 15 | DCH | 7417 | WG | Baseline FFQ | Q4 versus Q1 | M:0.80(0.73,0.88) F: 0.85(0.77,0.94) | 4, 5, 6, 12, 17, 26 | 7 |
| Hu et al. (2020) | United States | 30–55 | F: 69,139 | 30 | NHS | 8170 | WG | Repeated FFQ | C5 versus C1 | 0.68(0.63, 0.73) | 1, 3, 5, 6, 7, 8, 13, 14, 15, 16 | 7 |
| Hu et al. (2020) | United States | 25–42 | F: 89,120 | 26 | NHS II | 7072 | WG | Repeated FFQ | C5 versus C1 | 0.73 (0.68, 0.80) | 1, 3, 5, 6, 7, 8, 13, 14, 15, 16. | 7 |
| Hu et al. (2020) | United States | 40–75 | M: 36,525 | 30 | HPFS | 3387 | WG | Repeated FFQ | C5 versus C1 | 0.72 (0.64, 0.81) | 1, 3, 5, 6, 7, 8, 13, 14, 15, 16 | 7 |
Abbreviations: BMI, body mass index; BWHS, Black Women's Health Study; C, category; CI, confidence interval; DCH, Danish Diet, Cancer, and Health cohort; EPIC‐Postdom study, European Prospective Investigation into Cancer and Nutrition; F, female; FFQ, food frequency questionnaire; FPS, Finnish prospective study; HPFS, health professional follow‐up study; HR, hazard ratio; lWHS, Iowa Women's Health Study; M, male; MDC, Malmö Diet and Cancer Study; NHS I, nurse health study I; NHS II, nurse health study II; NOS, Newcastle‐Ottawa Scale; Q, quintile or quartile; T, tertile; TEE, total energy intake; WG, whole grain.
Adjusted factors codes: 1 – Age, 2 – sex, 3 – Race/Ethnicity, 4 – BMI, 5 – Smoking status, 6 – Alcohol intake, 7 – Multivitamin use, 8 – Physical activity, 9 – Leisure time physical activity, 10 – Sports activity, 11 – Strenuous physical activity, 12 – Cambridge physical activity index, 13 – Modified alternative healthy eating index, 14 – Family history of diabetes, 15 – Postmenopausal hormone use for women, 16 – Oral contraceptive use for women, 17 – Education level, 18 – Season, 19 – Income, 20 – Blood pressure, 21 – Waist circumference, 22 – waist‐to‐hip ratio, 23 – Occupational activity, 24 – Geographic area, 25 – TEE, 26 – Red and processed meat intake, 27 – Dietary variables (according to dietary method version), 28 – butter, margarine and vegetable fat, 29 – Coffee consumption, 30 – Sugar‐sweetened soft drink consumption, 31 – Low‐fat dairy consumption, 32 – Fruit and berries, and vegetables.