TABLE 2.
Baseline characteristics by dietary GI quintile and incidence of depression 3 y later1
| Dietary GI quintile |
Incident depression 3 y later |
|||||||||
| Baseline characteristics | n | First (low) | Second | Third | Fourth | Fifth (high) | P2 | Yes | No | P2 |
| Total n | 69,954 | 13,990 | 13,991 | 13,991 | 13,991 | 13,991 | 4643 | 65,311 | ||
| Depression, n | 4643 | 807 | 849 | 876 | 988 | 1123 | <0.0001 | |||
| Median GI | 47.0 | 49.8 | 51.7 | 53.5 | 56.3 | |||||
| Race-ethnicity, % | <0.0001 | <0.0001 | ||||||||
| American Indian/Alaskan native | 928 | 1.4 | 1.3 | 1.2 | 1.2 | 1.5 | 8.2 | 91.8 | ||
| Asian/Pacific Islander | 2061 | 2.5 | 3.3 | 3.3 | 3.5 | 2.2 | 3.7 | 96.3 | ||
| Black | 4328 | 4.8 | 4.0 | 5.1 | 6.5 | 10.7 | 8.1 | 91.9 | ||
| Hispanic | 1879 | 3.3 | 2.7 | 2.5 | 2.7 | 2.3 | 11.2 | 88.8 | ||
| White, not of Hispanic origin | 60,570 | 87.7 | 88.4 | 87.8 | 85.9 | 83.1 | 6.5 | 93.5 | ||
| Missing | 188 | 0.3 | 0.3 | 0.2 | 0.3 | 0.3 | 5.9 | 94.1 | ||
| Education (college graduate or higher), % | 31,285 | 52.0 | 49.8 | 46.3 | 41.9 | 33.6 | <0.0001 | 36.7 | 45.3 | <0.0001 |
| Annual income ≥$50,000, % | 28,309 | 47.1 | 45.2 | 42.9 | 40.5 | 35.6 | <0.0001 | 35.3 | 42.7 | <0.0001 |
| Diabetes, % | 3217 | 4.6 | 4.3 | 4.5 | 4.7 | 4.9 | 0.2470 | 6.8 | 4.4 | <0.0001 |
| Hypertension, % | 21,958 | 29.1 | 29.9 | 31.4 | 32.5 | 34.1 | <0.0001 | 34.4 | 31.2 | <0.0001 |
| Myocardial infarction, % | 1458 | 1.9 | 1.8 | 1.9 | 2.3 | 2.4 | 0.0007 | 2.4 | 2.1 | 0.1738 |
| Stroke, % | 821 | 1.1 | 1.0 | 1.1 | 1.3 | 1.4 | 0.0562 | 1.8 | 1.1 | <0.0001 |
| Cardiovascular disease, % | 12,436 | 17.2 | 17.8 | 18.1 | 17.7 | 18.1 | 0.0943 | 21.3 | 17.5 | <0.0001 |
| Cancer, % | 8804 | 12.5 | 12.8 | 13.1 | 12.4 | 12.1 | 0.1740 | 14.1 | 12.5 | 0.0008 |
| Alzheimer disease | 32 | 0.05 | 0.04 | 0.06 | 0.05 | 0.03 | 0.7050 | 0.09 | 0.04 | 0.0002 |
| Hormone replacement therapy, % | 34,193 | 50.8 | 50.7 | 49.2 | 48.3 | 45.5 | <0.0001 | 49.8 | 48.8 | 0.0002 |
| Alcohol intake, % | <0.0001 | <0.0001 | ||||||||
| Nondrinker | 7220 | 8.4 | 8.6 | 9.6 | 11.0 | 14.0 | 6.6 | 93.4 | ||
| Past drinker | 11,767 | 15.1 | 14.7 | 15.8 | 17.6 | 20.9 | 8.6 | 91.4 | ||
| <1 drink/mo | 7860 | 9.4 | 9.9 | 10.8 | 11.6 | 14.5 | 6.8 | 93.2 | ||
| <1 drink/wk | 14,043 | 19.0 | 20.3 | 20.5 | 21.0 | 19.6 | 6.7 | 93.3 | ||
| 1 to <7 drinks/wk | 19,047 | 28.7 | 30.6 | 29.1 | 26.7 | 21.2 | 5.8 | 94.2 | ||
| ≥7 drinks/wk | 9642 | 18.7 | 15.6 | 13.7 | 11.7 | 9.2 | 5.4 | 94.6 | ||
| Missing | 376 | 0.7 | 0.5 | 0.5 | 0.5 | 0.6 | 8.2 | 91.8 | ||
| Smoking status, % | <0.0001 | <0.0001 | ||||||||
| Never smoked | 35,617 | 48.6 | 51.6 | 51.4 | 51.8 | 51.2 | 6.2 | 93.8 | ||
| Past smoker | 29,869 | 45.9 | 43.3 | 42.4 | 41.5 | 40.4 | 6.7 | 93.3 | ||
| Current smoker | 3581 | 4.1 | 3.9 | 4.9 | 5.5 | 7.2 | 9.9 | 90.1 | ||
| Missing | 888 | 1.4 | 1.2 | 1.3 | 1.2 | 1.2 | 7.3 | 92.7 | ||
| Stressful life events, % | <0.0001 | <0.0001 | ||||||||
| First quintile | 20,107 | 29.3 | 29.7 | 29.4 | 28.4 | 27.0 | 2.4 | 97.6 | ||
| Second quintile | 8930 | 12.6 | 13.1 | 13.1 | 12.8 | 12.3 | 2.8 | 97.2 | ||
| Third quintile | 11,838 | 16.7 | 17.1 | 17.2 | 17.2 | 16.4 | 3.9 | 96.1 | ||
| Fourth quintile | 15,604 | 22.1 | 22.3 | 22.0 | 22.2 | 23.0 | 7.6 | 92.4 | ||
| Fifth quintile | 12,317 | 17.5 | 16.2 | 16.7 | 17.8 | 19.3 | 17.6 | 82.4 | ||
| Missing | 1159 | 1.8 | 1.6 | 1.7 | 1.7 | 1.6 | 9.6 | 90.4 | ||
| Social support, % | <0.0001 | <0.0001 | ||||||||
| First quintile | 14,317 | 20.2 | 19.5 | 20.3 | 20.5 | 21.9 | 10.4 | 89.6 | ||
| Second quintile | 14,632 | 21.0 | 20.7 | 20.8 | 21.3 | 20.8 | 7.4 | 92.7 | ||
| Third quintile | 10,506 | 14.4 | 15.3 | 15.2 | 15.4 | 14.8 | 5.6 | 94.4 | ||
| Fourth quintile | 13,700 | 19.1 | 20.2 | 19.4 | 19.7 | 19.4 | 5.3 | 94.7 | ||
| Fifth quintile | 15,201 | 22.8 | 22.2 | 22.2 | 20.8 | 20.7 | 4.2 | 95.9 | ||
| Missing | 1599 | 2.4 | 2.2 | 2.2 | 2.3 | 2.4 | 7.8 | 92.3 | ||
1
GI, glycemic index.
2
Differences by depression and GI quintiles were tested by using chi-square tests for categorical variables.