Table 5.
Caffeine consumption (mean ± SE mg/day) of Marine Corps consumers (≥1 time/week) by demographic, lifestyle, and military characteristics (p-values are from one-way analysis of variance).
| Variable | Strata | Any Caffeine | Coffee | Hot Tea | Other Tea | Cola | Other Soda | Energy Drink | Gum/Medication |
|---|---|---|---|---|---|---|---|---|---|
| Group | All (n = 846) | 232 ± 7 | 125 ± 5 | 7 ± 1 | 21 ± 3 | 15 ± 1 | 6 ± 1 | 43 ± 3 | 14 ± 3 |
| Gender | Men (n = 605) | 251 ± 9 | 137 ± 6 | 5 ± 1 | 24 ± 4 | 18 ± 1 | 7 ± 1 | 49 ± 4 | 11 ± 4 |
| Women (n = 241) | 188 ± 12 | 93 ± 8 | 15 ± 2 | 14 ± 4 | 9 ± 1 | 6 ± 2 | 28 ± 4 | 22 ± 5 | |
| p-value | <0.01 | <0.01 | <0.01 | 0.10 | <0.01 | 0.75 | <0.01 | 0.10 | |
| Age (years) | 18–24 (n = 237) | 214 ± 14 | 94 ± 9 | 10 ± 2 | 26 ± 6 | 12 ± 2 | 10 ± 3 | 45 ± 5 | 16 ± 4 |
| 25–29 (n = 212) | 212 ± 16 | 109 ± 10 | 6 ± 2 | 19 ± 6 | 13 ± 2 | 3 ± 1 | 44 ± 6 | 17 ± 10 | |
| 30–39 (n = 285) | 248 ± 12 | 140 ± 9 | 6 ± 1 | 18 ± 4 | 19 ± 2 | 7 ± 2 | 49 ± 5 | 11 ± 3 | |
| ≥40 (n = 112) | 270 ± 20 | 181 ± 17 | 9 ± 3 | 21 ± 6 | 18 ± 3 | 4 ± 2 | 23 ± 7 | 13 ± 5 | |
| p-value | 0.04 | <0.01 | 0.19 | 0.64 | 0.08 | 0.07 | 0.04 | 0.89 | |
| Education | Some high school/high school graduate (n = 230) | 221 ± 15 | 101 ± 10 | 8 ± 2 | 29 ± 6 | 14 ± 2 | 10 ± 3 | 46 ± 5 | 13 ± 4 |
| Some college/Associate’s degree (n = 382) | 230 ± 11 | 119 ± 8 | 7 ± 1 | 21 ± 4 | 15 ± 2 | 7 ± 2 | 48 ± 4 | 13 ± 3 | |
| Bachelor’s/Graduate degree (n = 234) | 247 ± 15 | 158 ± 10 | 8 ± 2 | 12 ± 3 | 18 ± 2 | 2 ± 1 | 32 ± 6 | 17 ± 10 | |
| p-value | 0.44 | <0.01 | 0.93 | 0.07 | 0.43 | 0.02 | 0.07 | 0.89 | |
| Marital status | Single (n = 256) | 216 ± 13 | 104 ± 9 | 12 ± 2 | 25 ± 6 | 12 ± 2 | 7 ± 2 | 41 ± 5 | 15 ± 4 |
| Married (n = 590) | 240 ± 9 | 134 ± 6 | 5 ± 1 | 19 ± 3 | 17 ± 1 | 6 ± 1 | 45 ± 4 | 14 ± 4 | |
| p-value | 0.14 | <0.01 | <0.01 | 0.27 | 0.02 | 0.53 | 0.53 | 0.87 | |
| Race/ethnicity | White (n = 533) | 257 ± 10 | 143 ± 7 | 6 ± 1 | 20 ± 3 | 18 ± 36 | 7 ± 1 | 48 ± 4 | 14 ± 5 |
| Black (n = 80) | 178 ± 23 | 84 ± 13 | 8 ± 3 | 20 ± 9 | 10 ± 3 | 6 ± 5 | 35 ± 8 | 15 ± 6 | |
| Hispanic (n = 166) | 200 ± 14 | 104 ± 9 | 9 ± 2 | 24 ± 8 | 12 ± 2 | 2 ± 1 | 34 ± 5 | 14 ± 4 | |
| Other (n = 67) | 182 ± 17 | 80 ± 12 | 11 ± 3 | 21 ± 5 | 11 ± 3 | 10 ± 4 | 38 ± 8 | 12 ± 9 | |
| p-value | <0.01 | <0.01 | 0.43 | 0.94 | 0.02 | 0.25 | 0.18 | 0.99 | |
| Body mass index (kg/m2) | <25.0 (n = 355) | 202 ± 11 | 105 ± 8 | 9 ± 1 | 23 ± 4 | 15 ± 2 | 9 ± 2 | 33 ± 4 | 10 ± 3 |
| 25.0–29.9 (n = 440) | 259 ± 11 | 142 ± 7 | 6 ± 1 | 20 ± 4 | 16 ± 1 | 5 ± 1 | 51 ± 4 | 18 ± 6 | |
| ≥30.0 (n = 42) | 217 ± 32 | 109 ± 22 | 3 ± 1 | 18 ± 8 | 16 ± 5 | 1 ± 1 | 55 ± 16 | 15 ± 7 | |
| p-value | <0.01 | <0.01 | 0.21 | 0.88 | 0.95 | 0.10 | <0.01 | 0.47 | |
| Alcohol consumption | None (n = 195) | 190 ± 17 | 86 ± 10 | 4 ± 1 | 19 ± 5 | 17 ± 3 | 9 ± 2 | 30 ± 5 | 26 ± 12 |
| <1.34 g/day(n = 161) | 213 ± 15 | 103 ± 10 | 13 ± 3 | 20 ± 7 | 10 ± 2 | 8 ± 3 | 42 ± 7 | 16 ± 5 | |
| 1.34–3.99 g/day (n = 167) | 237 ± 18 | 138 ± 14 | 5 ± 1 | 24 ± 7 | 17 ± 3 | 5 ± 1 | 40 ± 6 | 10 ± 3 | |
| 4.00–8.93 g/day (n = 155) | 258 ± 17 | 145 ± 12 | 8 ± 2 | 21 ± 6 | 16 ± 3 | 6 ± 3 | 49 ± 6 | 14 ± 5 | |
| >8.93 g/day (n = 168) | 270 ± 15 | 159 ± 12 | 9 ± 2 | 21 ± 5 | 17 ± 3 | 4 ± 1 | 58 ± 8 | 2 ± 1 | |
| p-value | <0.01 | <0.01 | <0.01 | 0.99 | 0.21 | 0.51 | 0.02 | 0.14 | |
| Aerobic exercise duration | <101 min/week (n = 191) | 234 ± 15 | 126 ± 10 | 7 ± 2 | 17 ± 5 | 18 ± 2 | 8 ± 3 | 50 ± 7 | 6 ± 3 |
| 101–180 min/week (n = 192) | 237 ± 14 | 130 ± 11 | 5 ± 1 | 24 ± 8 | 16 ± 3 | 7 ± 2 | 42 ± 6 | 13 ± 4 | |
| 181–290 min/week (n = 230) | 238 ± 14 | 129 ± 11 | 9 ± 2 | 22 ± 5 | 16 ± 2 | 5 ± 2 | 44 ± 5 | 13 ± 4 | |
| ≥291 min/week (n = 229) | 224 ± 16 | 117 ± 10 | 8 ± 2 | 20 ± 5 | 12 ± 2 | 5 ± 2 | 39 ± 5 | 23 ± 10 | |
| p-value | 0.89 | 0.80 | 0.32 | 0.85 | 0.16 | 0.65 | 0.58 | 0.28 | |
| Resistance training duration | <46 min/week (n = 173) | 273 ± 19 | 155 ± 15 | 9 ± 2 | 23 ± 6 | 21 ± 3 | 11 ± 3 | 42 ± 7 | 12 ± 4 |
| 46–135 min/week (n = 222) | 225 ± 14 | 123 ± 10 | 5 ± 1 | 25 ± 7 | 14 ± 2 | 6 ± 2 | 43 ± 6 | 9 ± 3 | |
| 136–270 min/week (n = 219) | 208 ± 12 | 122 ± 10 | 8 ± 2 | 12 ± 2 | 15 ± 2 | 4 ± 1 | 35 ± 4 | 11 ± 3 | |
| ≥271 min/week (n = 224) | 235 ± 16 | 107 ± 8 | 9 ± 2 | 24 ± 6 | 12 ± 2 | 6 ± 2 | 52 ± 6 | 25 ± 11 | |
| p-value | 0.03 | 0.02 | 0.22 | 0.26 | 0.03 | 0.21 | 0.22 | 0.21 | |
| Sleep duration | ≤4 h/night (n = 41) | 378 ± 53 | 151 ± 41 | 15 ± 8 | 67 ± 26 | 23 ± 6 | 12 ± 9 | 71 ± 15 | 39 ± 17 |
| 5–6 h/night (n = 437) | 249 ± 10 | 132 ± 7 | 7 ± 1 | 22 ± 4 | 15 ± 1 | 7 ± 2 | 52 ± 4 | 15 ± 3 | |
| 7–8 h/night (n = 333) | 187 ± 9 | 111 ± 7 | 8 ± 1 | 14 ± 3 | 16 ± 2 | 4 ± 1 | 30 ± 4 | 4 ± 2 | |
| ≥9 h/night (n = 10) | 141 ± 44 | 63 ± 19 | 0 ± 0 | 7 ± 3 | 7 ± 5 | 27 ± 15 | 35 ± 10 | 3 ± 3 | |
| p-value | <0.01 | 0.08 | 0.14 | <0.01 | 0.36 | 0.05 | <0.01 | <0.01 | |
| Rank | Junior enlisted (n = 222) | 206 ± 15 | 89 ± 10 | 10 ± 2 | 30 ± 7 | 11 ± 2 | 9 ± 2 | 45 ± 5 | 13 ± 4 |
| Senior enlisted (n = 424) | 243 ± 11 | 124 ± 7 | 7 ± 1 | 21 ± 4 | 17 ± 2 | 7 ± 2 | 48 ± 4 | 19 ± 6 | |
| Warrant officer (n = 30) | 283 ± 43 | 163 ± 28 | 6 ± 4 | 15 ± 10 | 24 ± 8 | 5 ± 4 | 44 ± 16 | 27 ± 19 | |
| Junior officer (n = 104) | 217 ± 17 | 154 ± 14 | 5 ± 1 | 6 ± 1 | 13 ± 2 | 2 ± 1 | 37 ± 10 | 1 ± 1 | |
| Senior officer (n = 66) | 253 ± 20 | 187 ± 19 | 11 ± 5 | 14 ± 8 | 23 ± 5 | 1 ± 1 | 18 ± 60 | 1 ± 1 | |
| p-value | 0.13 | <0.01 | 0.30 | 0.12 | 0.02 | 0.25 | 0.08 | 0.23 | |
| Special Operations | No (n = 827) | 233 ± 8 | 125 ± 5 | 7 ± 1 | 21 ± 3 | 15 ± 1 | 6 ± 1 | 44 ± 3 | 14 ± 3 |
| Yes (n = 16) | 216 ± 48 | 154 ± 42 | 7 ± 5 | 9 ± 5 | 21 ± 7 | 1 ± 1 | 24 ± 10 | 0 ± 0 | |
| p-value | 0.75 | 0.45 | 0.99 | 0.54 | 0.50 | 0.43 | 0.36 | 0.53 |
Abbreviation: SE=standard error