TABLE 1.
Population characteristics of the Framingham Offspring Study and the 3 cohorts conducting dietary pattern analyses by using reduced rank regression (RRR) for type 2 diabetes mellitus (T2DM) risk prediction1
| Framingham Offspring Study | NHS2 |
EPIC Study2 |
Whitehall II Study2 | |||
| Cases | Controls | Cases | Controls | |||
| Subject characteristics3 | ||||||
| No. of subjects | 2879 | 656 | 694 | 192 | 382 | 7339 |
| Men (%) | 54.5 | 0 | 0 | 58.9 | 58.9 | 69.6 |
| White (%) | ≈100 | 94.6 | 94.6 | ≈100 | ≈100 | 90.4 |
| Age (y) | 54.2 ± 9.74 | 56.3 ± 6.9 | 56.2 ± 6.9 | 55.5 ± 6.8 | 55.5 ± 6.8 | 49.5 ± 8.6 |
| Current smoking (%)3 | 18.6 | 13.4 | 13.2 | 19.8 | 20.7 | 13.5 |
| Total energy (kcal/d) | 1871 ± 621 | 1817 ± 561 | 1769 ± 512 | 2211 ± 727 | 2177 ± 652 | 2160 ± 661 |
| BMI (kg/m2)3 | 27.1 ± 4.7 | 30.2 ± 5.6 | 26.1 ± 5.1 | 30.8 ± 4.8 | 26.7 ± 3.6 | 25.3 ± 3.4 |
| Hypertension (%)5 | 19.8 | — | — | 78.8 | 51.7 | 16.7 |
| Family history of T2DM (%)6 | 17.2 | 47.6 | 20.8 | — | — | — |
| Alcohol (g/d)3 | 10.7 ± 16.2 | 3.7 ± 7.1 | 6.4 ± 9.0 | 18.5 ± 28.2 | 16.1 ± 16.4 | 12.1 ± 17.1 |
| Study characteristcs7 | ||||||
| Years of FFQ collection | 1991–1995 | 1986 and 1990 | 1994–1998 | 1985–1988 | ||
| No. of items on the FFQ | 126 | 131 | 148 | 127 | ||
| No. of food groups7 | — | 39 | 48 | 71 | ||
| RRR response variables | BMI, glucose, HDL, triglycerides, systolic and diastolic blood pressures | Inflammatory cytokines8 | HDL cholesterol, glycated hemoglobin, C-reactive protein, adiponectin | Homeostasis model assessment of insulin resistance | ||
Values for the external cohorts were retrieved from previous publications (5–7, 14, 16–19). NHS, Nurses' Health Study; EPIC, European Prospective Investigation into Cancer Potsdam Study; FFQ, food-frequency questionnaire.
The NHS and EPIC had a prospective nested case-control design (5, 6), whereas the Framingham Offspring Study (FOS) and the Whitehall II Study (WS) had a prospective cohort design (7, 8). The NHS applied matching by year of birth, date of blood draw, race-ethnicity, and time of the blood draw. EPIC applied matching by age.
The statistics of the FOS were different from those of the 3 cohorts (P < 0.0001) according to a chi-square test for categorical variables and an independent t test for continuous variables. Proportions of men and whites and the mean age of the FOS were different from those of the NHS and WS cohorts (P < 0.0001) but not from those of the EPIC cohort (P > 0.05).
Mean ± SD (all such values).
On the basis of self-report of prior diagnosis or hypertension treatment in EPIC and systolic blood pressure >140 mm Hg or diastolic blood pressure >90 mm Hg in the WS and FOS. With the definition used in the EPIC, 30.4% of the FOS population had hypertension.
Parental history for the FOS cohort and family history of first-order relatives of the NHS cohort.
All studies used FFQs. The NHS had repeated measurements at the 2 time points and took the average of each food group, whereas the other studies had single measurements. The FOS applied all 3 food groupings reported in the 3 external studies.
Tumor necrosis factor α receptor 2, interleukin-6, C-reactive protein, E-selectin, and intracellular and vascular cell adhesion molecules.