Table 1.
| a. Comparison of AM and PM samples of adolescents in the National Health and Nutrition Examination Survey, 1999–2008 | ||||||
|---|---|---|---|---|---|---|
| Boys |
Girls |
|||||
| Characteristic | AM (N=2,335) |
PM (N=2,417) |
p- value* |
AM (N=2,139) |
PM (N=2,470) |
p- value* |
| Age (years; mean (SD)) | 15.6 (2.3) | 15.4 (2.3) | 0.18 | 15.6 (2.2) | 15.4 (2.2) | 0.15 |
| Race-ethnicity (%) | 0.35 | 0.84 | ||||
| Non-Hispanic white | 60.9 | 61.7 | 62.1 | 60.3 | ||
| Non-Hispanic black | 15.4 | 13.6 | 14.7 | 14.9 | ||
| Mexican American | 11.2 | 11.9 | 11.4 | 11.5 | ||
| Other | 12.5 | 12.7 | 11.8 | 13.3 | ||
| Viral hepatitis (%) | ||||||
| B | 0.13 | 0 | 0.18 | 0.021 | 0.020 | 0.96 |
| C | 0.0086 | 0.013 | 0.77 | 0.043 | 0.065 | 0.77 |
| B or C | 0.14 | 0.013 | 0.20 | 0.065 | 0.085 | 0.79 |
| BMI (kg/m2; mean (SD)) | 23.2 (5.5) | 23.4 (5.5) | 0.40 | 23.5 (5.7) | 23.7 (5.7) | 0.38 |
| Waist circumference (cm; mean (SD)) | 81.4 (14.9) | 82.0 (14.7) | 0.43 | 80.6 (13.8) | 81.0 (13.5) | 0.60 |
| Doctor-diagnosed diabetes (%) | 1.1 | 0.29 | 0.058 | 0.65 | 0.18 | 0.064 |
| Hemoglobin A1C≥6.5% (%) | 1.0 | 0.33 | 0.051 | 0.50 | 0.10 | 0.046 |
| Abnormal glucose status (%)† | 1.3 | 0.42 | 0.054 | 0.72 | 0.25 | 0.075 |
| Serum total cholesterol (mg/dL; mean (SD)) | 158 (32) | 159 (31) | 0.33 | 164 (30) | 165 (31) | 0.44 |
| Fasting time (hours; mean (SD)) | 11.8 (3.7) | 7.3 (6.0) | <0.001 | 12.2 (4.4) | 7.2 (6.0) | <0.001 |
| b. Comparison of AM and PM samples of adults in the National Health and Nutrition Examination Survey, 1999–2008 | ||||||
|---|---|---|---|---|---|---|
| Men |
Women |
|||||
| Characteristic | AM (N=5,427) |
PM (N=5,614) |
p- value* |
AM (N=5,808) |
PM (N=6,121) |
p- value* |
| Age (years; mean (SD)) | 45.7 (16.3) | 45.6 (16.4) | 0.63 | 47.5 (17.2) | 46.9 (17.2) | 0.19 |
| Race-ethnicity (%) | 0.95 | 0.064 | ||||
| Non-Hispanic white | 71.8 | 72.0 | 71.4 | 71.1 | ||
| Non-Hispanic black | 9.6 | 9.8 | 11.8 | 10.8 | ||
| Mexican American | 8.5 | 8.3 | 6.8 | 7.2 | ||
| Other | 10.0 | 9.9 | 9.9 | 10.9 | ||
| Viral hepatitis (%) | ||||||
| B | 0.45 | 0.48 | 0.85 | 0.35 | 0.07 | 0.002 |
| C | 2.4 | 2.3 | 0.79 | 1.4 | 1.3 | 0.68 |
| B or C | 2.8 | 2.8 | 0.87 | 1.7 | 1.3 | 0.17 |
| Alcohol consumption (drinks/day; %) | 0.87 | 0.30 | ||||
| 0 | 23.5 | 24.2 | 35.9 | 34.6 | ||
| <1 | 52.9 | 52.1 | 56.4 | 58.3 | ||
| 1–2 | 13.3 | 13.6 | 6.0 | 5.6 | ||
| >2 | 10.3 | 10.1 | 1.7 | 1.5 | ||
| BMI (kg/m2; mean (SD)) | 28.2 (5.8) | 28.2 (5.6) | 0.95 | 28.3 (6.9) | 28.4 (7.2) | 0.48 |
| Waist circumference (cm; mean (SD)) | 100 (15.1) | 100 (14.7) | 0.95 | 93.8 (15.7) | 94.0 (16.1) | 0.68 |
| Doctor-diagnosed diabetes (%) | 7.4 | 7.5 | 0.85 | 7.4 | 7.3 | 0.90 |
| Hemoglobin A1C ≥6.5% (%) | 7.0 | 7.0 | 0.94 | 5.8 | 6.2 | 0.49 |
| Abnormal glucose status (%)† | 9.5 | 9.8 | 0.55 | 8.9 | 8.9 | 0.90 |
| Serum total cholesterol (mg/dL; mean (SD)) | 198 (42) | 200 (44) | 0.031 | 202 (42) | 203 (40) | 0.046 |
| Smoking (%) | 0.044 | 0.13 | ||||
| Never | 42.9 | 43.7 | 56.8 | 58.9 | ||
| Former | 29.8 | 28.8 | 22.8 | 20.2 | ||
| <1 pack/day | 14.1 | 15.5 | 12.7 | 12.8 | ||
| ≥1 pack/day | 13.2 | 12.0 | 7.7 | 8.1 | ||
| Fasting time (hours; mean (SD)) | 11.9 (4.1) | 6.9 (5.4) | <0.001 | 12.0 (3.9) | 6.7 (5.5) | <0.001 |
| Caffeine intake (mg /day; mean (SD))‡ | 218 (262) | 216 (254) | 0.77 | 165 (195) | 159 (209) | 0.31 |
SD, standard deviation
*
From chi-squared test for categorical variables or t-test for continuous variables.
†
Doctor-diagnosed diabetes or hemoglobin A1C≥6.5%.
‡
Subgroup with dietary interview in NHANES 2001–08 (n=18,010).