TABLE 2.
HR estimates for PCa by intake of dairy product and dairy calcium in the PHS (n = 21,660)1
| Category 1 | Category 2 | Category 3 | Category 4 | Category 5 | P-trend2 | |
| All dairy food3 | ||||||
| Cases/person-years | 388/76,216 | 446/86,740 | 586/98,871 | 910/137,667 | 458/69,738 | |
| Age-adjusted | 1.00 | 1.00 (0.88, 1.15) | 1.11 (0.98, 1.26) | 1.19 (1.06, 1.34) | 1.15 (1.00, 1.31) | 0.0034 |
| Multivariable-adjusted5 | 1.00 | 0.96 (0.83, 1.11) | 1.07 (0.93, 1.23) | 1.15 (0.99, 1.32) | 1.12 (0.93, 1.35) | 0.06 |
| Whole milk6 | ||||||
| Cases/person-years | 1674/279,675 | 504/86,554 | 273/47,723 | 244/39,924 | ||
| Age-adjusted | 1.00 | 0.97 (0.88, 1.08) | 0.89 (0.78, 1.01) | 0.89 (0.78, 1.02) | 0.04 | |
| Multivariable-adjusted5 | 1.00 | 1.02 (0.92, 1.13) | 0.93 (0.81, 1.07) | 0.95 (0.81, 1.10) | 0.32 | |
| Skim/low-fat milk6 | ||||||
| Cases/person-years | 895/160,367 | 531/98,250 | 579/94,591 | 724/104,959 | ||
| Age-adjusted | 1.00 | 1.05 (0.94, 1.17) | 1.17 (1.05, 1.29) | 1.21 (1.10, 1.34) | <0.0014 | |
| Multivariable-adjusted5 | 1.00 | 1.02 (0.91, 1.14) | 1.12 (1.00, 1.25) | 1.19 (1.06, 1.33) | 0.0014 | |
| Hard cheese6 | ||||||
| Cases/person-years | 197/35,560 | 1207/208,462 | 1175/190,531 | 178/28,270 | ||
| Age-adjusted | 1.00 | 1.05 (0.90, 1.22) | 1.12 (0.96, 1.30) | 1.10 (0.90, 1.35) | 0.14 | |
| Multivariable-adjusted5 | 1.00 | 1.01 (0.87, 1.18) | 1.07 (0.91, 1.25) | 1.05 (0.85, 1.30) | 0.32 | |
| Ice cream6 | ||||||
| Cases/person-years | 455/75,120 | 1415/251,406 | 805/124,783 | 84/12,177 | ||
| Age-adjusted | 1.00 | 0.96 (0.86, 1.06) | 1.06 (0.95, 1.19) | 1.05 (0.83, 1.32) | 0.06 | |
| Multivariable-adjusted5 | 1.00 | 0.95 (0.85, 1.06) | 1.02 (0.90, 1.15) | 1.03 (0.80, 1.32) | 0.26 | |
| Cold breakfast cereal6 | ||||||
| Cases/person-years | 743/131,310 | 654/120,759 | 678/112,540 | 679/98,469 | ||
| Age-adjusted | 1.00 | 0.96 (0.86, 1.06) | 1.02 (0.92, 1.13) | 1.11 (1.00, 1.23) | 0.014 | |
| Multivariable-adjusted5 | 1.00 | 0.95 (0.85, 1.06) | 1.00 (0.88, 1.12) | 1.06 (0.93, 1.22) | 0.17 | |
| Calcium from dairy food7 | ||||||
| Cases/person-years | 487/95,147 | 516/95,489 | 578/93,334 | 598/92,688 | 609/91,575 | |
| Age-adjusted | 1.00 | 1.04 (0.92, 1.18) | 1.15 (1.02, 1.30) | 1.16 (1.03, 1.31) | 1.17 (1.03, 1.31) | 0.0044 |
| Multivariable-adjusted5 | 1.00 | 1.01 (0.89, 1.15) | 1.12 (0.98, 1.28) | 1.12 (0.97, 1.30) | 1.14 (0.97, 1.34) | 0.07 |
Values are HR (95% CI). FDR, false-discovery rate; PCa, prostate cancer; PHS, Physicians’ Health Study.
Calculated in a separate regression model with the median intake levels in each category as a continuous variable.
Based on the consumption of 5 major dairy foods (whole milk, skim/low-fat milk, hard cheese, ice cream, and cold breakfast cereal) assessed from 1982 to 1984. The 5 intake level groups are: ≤0.5 servings/d, >0.5–1.0 serving/d, >1.0–1.5 servings/d, >1.5–2.5 servings/d, and >2.5 servings/d. One serving of whole milk, skim/low-fat milk, or cold breakfast cereal = 237 mL; 1 serving of ice cream = 214 g; 1 serving of hard cheese = 28 g.
FDR < 0.05.
Adjusted for baseline measures of age (y), cigarette smoking (never, past, current), vigorous exercise (exercise vigorously to a sweat more than twice per week or not), alcohol intake (drink alcoholic beverages every day or not), race (Caucasian, non-Caucasian), BMI (normal weight, overweight, obese), baseline diabetes status (yes, no), red meat consumption (servings/wk), total energy intake from recorded food items (kcal), assignment in the original aspirin trial (treatment, placebo), and assignment in the original β-carotene trial (treatment, placebo). In addition, the models for whole milk and skim/low-fat milk were mutually adjusted for each other (rarely, ≤1 serving/wk, 2–6 servings/wk, and ≥1 serving/d).
The 4 intake level groups were: rarely, ≤1 serving/wk, 2–6 servings/wk, and ≥1 serving/d.
The 5 intake level groups were categorized according to quintiles.