Table 1.
General characteristics according to the frequency of coffee consumption in Korean adults
| Characteristic | Coffee consumption (cup/d) |
P-value* | ||
|---|---|---|---|---|
| <1 (n=3,384) | 1–2 (n=4,620) | ≥3 (n=1,748) | ||
| Age (y) | 43.92±0.50 | 47.40±0.52 | 45.05±0.54 | <0.001 |
| Men (%) | 41.3 (1.1) | 41.8 (0.8) | 63.6 (1.3) | <0.001 |
| Body mass index (kg/m2) | 23.22±0.08 | 23.77±0.96 | 24.04±0.13 | <0.001 |
| Rural residence (%) | 55.0 (1.7) | 51.8 (1.6) | 55.5 (2.0) | 0.039 |
| Working outdoors (%) | 22.2 (1.2) | 27.7 (1.2) | 35.3 (1.7) | <0.001 |
| Education (%) | <0.001 | |||
| Middle school or less | 31.8 (1.2) | 32.2 (1.2) | 23.5 (1.4) | |
| High school | 37.8 (1.2) | 35.3 (1.1) | 40.7 (1.4) | |
| University or more | 30.4 (1.1) | 32.5 (1.1) | 35.8 (1.5) | |
| Physically active (%) | 17.8 (0.9) | 16.4 (0.7) | 14.1 (1.0) | 0.036 |
| Duration of sleep time (h/d) (%) | <0.001 | |||
| Less than 6 | 10.0 (0.7) | 6.9 (0.5) | 5.7 (0.7) | |
| 6–8 | 75.1 (0.9) | 80.2 (0.8) | 81.7 (1.3) | |
| 9 or more | 14.9 (0.7) | 12.8 (0.7) | 12.6 (1.0) | |
| Alcohol drinking (%) | 60.2 (1.2) | 63.3 (1.1) | 72.4 (1.4) | <0.001 |
| Smoking (%) | <0.001 | |||
| Never | 66.8 (1.1) | 61.9 (0.8) | 37.0 (1.3) | |
| Past | 15.8 (0.8) | 18.5 (0.7) | 18.5 (1.1) | |
| Current | 17.4 (0.9) | 19.6 (0.8) | 44.5 (1.4) | |
| History of ophthalmic surgery (%) | 12.6 (0.7) | 11.9 (0.6) | 8.1 (0.7) | <0.001 |
| Hypertension (%) | 17.3 (0.8) | 18.8 (0.7) | 14.3 (1.1) | 0.001 |
| Diabetes (%) | 7.7 (0.6) | 7.0 (0.4) | 4.0 (0.5) | <0.001 |
| Hyperlipidemia (%) | 8.1 (0.6) | 8.6 (0.5) | 7.5 (0.8) | 0.414 |
| Osteoarthritis (%) | 9.7 (0.5) | 9.8 (0.5) | 4.6 (0.6) | <0.001 |
| Rheumatoid arthritis (%) | 1.9 (0.2) | 1.7 (0.2) | 1.5 (0.3) | 0.688 |
| Thyroid disease (%) | 3.9 (0.4) | 3.8 (0.3) | 2.2 (0.4) | 0.01 |
| Renal disease (%) | 0.4 (0.1) | 0.3 (0.1) | 0.1 (0.1) | 0.329 |
| Depression (%) | 4.7 (0.5) | 3.6 (0.3) | 2.5 (0.5) | 0.004 |
| Dry eye syndrome (%) | 9.2 (0.7) | 8.8 (0.5) | 6.3 (0.7) | 0.006 |
Values are presented as mean±SE or % (SE).
SE, standard error.
*
By analysis of variance or chi-square test.