TABLE 2.
HRs (95% CIs) for type 2 diabetes according to categories of updated 4-y changes in total, low-fat, and high-fat dairy product consumption1
| Changes in dairy product consumption frequency | ||||||
|---|---|---|---|---|---|---|
| Decrease | No change or relatively stable | Increase | P values for trend | |||
| Total dairy | >1.00 serving/d | >0.14 to 1.00 serving/d | ±0.14 serving/d | >0.14 to 1.00 serving/d | >1.00 serving/d | |
| HPFS | ||||||
| Median change | −1.67 | −0.43 | 0.00 | 0.43 | 1.65 | |
| Cases/person-years | 332/71,591 | 606/139,354 | 342/85,151 | 665/139,466 | 355/69,219 | |
| Model 1 | 1.19 (1.02, 1.38) | 1.10 (0.97, 1.26) | 1.00 | 1.17 (1.03, 1.34) | 1.27 (1.09, 1.47) | 0.23 |
| Model 2 | 1.13 (0.95, 1.35) | 1.09 (0.95, 1.25) | 1.00 | 1.10 (0.97, 1.26) | 1.12 (0.96, 1.31) | 0.86 |
| NHS | ||||||
| Median change | −1.71 | −0.49 | 0.00 | 0.49 | 1.65 | |
| Cases/person-years | 536/198,684 | 1535/319,264 | 773/161,349 | 1598/309,624 | 1022/189,919 | |
| Model 1 | 1.13 (1.03, 1.24) | 1.01 (0.93, 1.10) | 1.00 | 1.06 (0.98, 1.16) | 1.07 (0.97, 1.17) | 0.47 |
| Model 2 | 1.08 (0.97, 1.19) | 1.00 (0.92, 1.10) | 1.00 | 1.04 (0.95, 1.13) | 0.97 (0.89, 1.07) | 0.13 |
| NHS II | ||||||
| Median change | −1.82 | −0.50 | 0.00 | 0.50 | 1.82 | |
| Cases/person-years | 742/237,596 | 817/267,867 | 420/121,069 | 912/250,598 | 722/222,459 | |
| Model 1 | 1.01 (0.89, 1.13) | 0.92 (0.81, 1.03) | 1.00 | 1.04 (0.93, 1.17) | 0.97 (0.85, 1.09) | 0.98 |
| Model 2 | 1.14 (1.00, 1.31) | 0.94 (0.84, 1.06) | 1.00 | 1.03 (0.91, 1.15) | 0.92 (0.81, 1.04) | 0.006 |
| Pooled2 | ||||||
| Model 2 | 1.11 (1.03, 1.19) | 1.00 (0.94, 1.07) | 1.00 | 1.05 (0.98, 1.11) | 0.98 (0.92, 1.05) | 0.008 |
| P for heterogeneity | 0.75 | 0.31 | — | 0.66 | 0.13 | 0.22 |
| Low-fat dairy | >0.50 serving/d | >0.07 to 0.50 serving/d | ±0.07 serving/d | >0.07 to 0.50 serving/d | >0.50 serving/d | |
| HPFS | ||||||
| Median change | −1.02 | −0.28 | 0.00 | 0.28 | 1.00 | |
| Cases/person-years | 400/87,965 | 480/100,820 | 434/104,515 | 475/109,289 | 511/102,194 | |
| Model 1 | 1.06 (0.92, 1.21) | 1.12 (0.98, 1.27) | 1.00 | 1.03 (0.91, 1.18) | 1.18 (1.04, 1.34) | 0.17 |
| Model 2 | 1.07 (0.91, 1.25) | 1.13 (0.98, 1.29) | 1.00 | 1.05 (0.92, 1.20) | 1.13 (0.98, 1.29) | 0.53 |
| NHS | ||||||
| Median change | −1.07 | −0.28 | 0.00 | 0.28 | 1.07 | |
| Cases/person-years | 1469/260,811 | 1088/219,594 | 789/163,960 | 1137/236,281 | 1510/298,196 | |
| Model 1 | 1.06 (0.97, 1.16) | 0.97 (0.89, 1.07) | 1.00 | 0.97 (0.89, 1.06) | 0.99 (0.91, 1.08) | 0.07 |
| Model 2 | 1.05 (0.96, 1.16) | 0.99 (0.90, 1.09) | 1.00 | 0.99 (0.90, 1.09) | 0.95 (0.87, 1.04) | 0.02 |
| NHS II | ||||||
| Median change | −1.14 | −0.28 | 0.00 | 0.28 | 1.14 | |
| Cases/person-years | 964/301,854 | 598/188,203 | 454/132,606 | 664/186,166 | 933/290,759 | |
| Model 1 | 0.98 (0.87, 1.09) | 0.92 (0.81, 1.04) | 1.00 | 1.01 (0.90, 1.14) | 0.94 (0.84, 1.05) | 0.59 |
| Model 2 | 1.12 (0.98, 1.28) | 1.00 (0.88, 1.14) | 1.00 | 1.05 (0.93, 1.19) | 0.97 (0.86, 1.09) | 0.02 |
| Pooled3 | ||||||
| Model 2 | 1.08 (1.00, 1.15) | 1.02 (0.95, 1.09) | 1.00 | 1.02 (0.96, 1.09) | 0.99 (0.93, 1.06) | 0.006 |
| P for heterogeneity | 0.74 | 0.29 | — | 0.66 | 0.11 | 0.16 |
| High-fat dairy | >0.50 serving/d | >0.07 to 0.50 serving/d | ±0.07 serving/d | >0.07 to 0.50 serving/d | >0.50 serving/d | |
| HPFS | ||||||
| Median change | −0.93 | −0.29 | 0.00 | 0.29 | 0.93 | |
| Cases/person-years | 372/78,329 | 505/123,807 | 630/135,625 | 475/105,265 | 318/61,755 | |
| Model 1 | 1.12 (0.99, 1.28) | 0.94 (0.83, 1.06) | 1.00 | 0.98 (0.87, 1.10) | 1.13 (0.99, 1.30) | 0.85 |
| Model 2 | 1.07 (0.91, 1.26) | 0.91 (0.80, 1.04) | 1.00 | 0.91 (0.80, 1.02) | 0.99 (0.86, 1.14) | 0.48 |
| NHS | ||||||
| Median change | −0.93 | −0.29 | 0.00 | 0.29 | 0.93 | |
| Cases/person-years | 904/201,659 | 1396/298,611 | 1428/283,095 | 1398/245,361 | 867/150,116 | |
| Model 1 | 1.01 (0.93, 1.10) | 1.00 (0.92, 1.07) | 1.00 | 1.11 (1.03, 1.19) | 1.12 (1.03, 1.22) | 0.003 |
| Model 2 | 0.88 (0.79, 0.97) | 0.91 (0.84, 0.99) | 1.00 | 1.03 (0.96, 1.11) | 0.99 (0.91, 1.08) | 0.008 |
| NHS II | ||||||
| Median change | −0.94 | −0.29 | 0.00 | 0.29 | 1.00 | |
| Cases/person-years | 630/198,992 | 780/264,081 | 752/236,377 | 767/220,593 | 684/179,546 | |
| Model 1 | 1.13 (1.02, 1.26) | 1.03 (0.93, 1.14) | 1.00 | 1.13 (1.02, 1.25) | 1.23 (1.11, 1.37) | 0.04 |
| Model 2 | 1.14 (1.00, 1.30) | 1.01 (0.91, 1.13) | 1.00 | 1.05 (0.95, 1.16) | 1.09 (0.98, 1.22) | 0.82 |
| Pooled4 | ||||||
| Model 2 | 0.99 (0.92, 1.06) | 0.94 (0.89, 1.00) | 1.00 | 1.01 (0.96, 1.07) | 1.02 (0.96, 1.09) | 0.09 |
| P for heterogeneity | 0.006 | 0.27 | — | 0.14 | 0.33 | 0.09 |
1Cox proportional hazards regression models were adjusted as follows. Model 1: adjusted for age and stratified by calendar year in 4-y intervals. Model 2: model 1 + race (Caucasian, non-Caucasian), family history of diabetes, updated history of hypercholesterolemia and high blood pressure, initial and change in smoking status (never to never, never to current, past to past, current to past, current to current, missing indicator), menopausal status and postmenopausal hormone use (premenopausal, postmenopausal + current use, postmenopausal + past use, postmenopausal + never use, missing indicator, in the NHS and NHS II), oral contraceptive use (never, current, past, missing indicator, in the NHS II), initial and change in physical activity level (metabolic equivalents of task per week, quintiles), initial BMI (in kg/m2) (<21.0, 21.0–24.9, 25.0–29.9, 30.0–31.9, >32.0), initial and changes in energy and alcohol intakes (quintiles), initial and change in Alternative Healthy Eating Index score (calculated without the alcohol component, quintiles), and initial total dairy product intake or initial intake of low-fat and high-fat dairy products (depending on the model, quintiles). Analyses on changes in low-fat and high-fat dairy product consumption were mutually adjusted for changes in high-fat or low-fat dairy product intake. Results of the 3 cohorts were pooled using an inverse variance–weighted, fixed-effect meta-analysis. P for heterogeneity was assessed using the Q statistic. HPFS, Health Professionals Follow-Up Study; NHS, Nurses’ Health Study.
2Total dairy P value for sex interaction = 0.34.
3Low-fat dairy P value for sex interaction = 0.04.
4High-fat dairy P value for sex interaction = 0.18.