TABLE 2.
Odds ratios (ORs) (95% confidence intervals) of healthy aging (n = 3721) assessed in 2014/2016 according to intake of protein in 1984/1986 among 48,762 participants in the Nurses’ Health Study (ORs >1 denote greater odds of healthy aging)
| Quintile of protein intake |
P-trend5 | ORs (95% CI) for 3%-energy increment | |||||
|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | |||
| Total protein | |||||||
| Healthy ager/participants (n) | 723/9752 | 781/9753 | 796/9752 | 748/9753 | 673/9752 | ||
| Median intake (IQR) % energy | 14.6 (13.6, 15.2) | 16.5 (16.2, 16.9) | 17.3 (17.6, 18.3) | 19.4 (19.0, 19.9) | 21.9 (21.1, 23.3) | ||
| Age-adjusted model1 | 1.00 | 1.12 (1.00, 1.25) | 1.18 (1.06, 1.31) | 1.16 (1.03, 1.29) | 1.11 (0.99, 1.25) | 0.06 | 1.05 (1.01, 1.09) |
| Multivariate model 12 | 1.00 | 0.96 (0.85, 1.08) | 0.99 (0.88, 1.11) | 0.95 (0.84, 1.07) | 0.89 (0.78, 1.01) | 0.07 | 0.97 (0.93, 1.01) |
| Multivariate model 23 | 1.00 | 0.99 (0.88, 1.11) | 1.06 (0.94, 1.20) | 1.08 (0.95, 1.21) | 1.08 (0.95, 1.23) | 0.11 | 1.05 (1.01, 1.10) |
| Animal protein | |||||||
| Healthy ager/participants (n) | 775/9752 | 758/9753 | 783/9752 | 754/9753 | 651/9752 | ||
| Median intake (IQR) % energy | 9.6 (8.6, 10.2) | 11.6 (11.2, 12.0) | 13.1 (12.7, 13.4) | 14.6 (14.2, 15.1) | 17.3 (16.3, 18.7) | ||
| Age-adjusted model1 | 1.00 | 0.99 (0.89, 1.10) | 1.03 (0.92, 1.14) | 1.01 (0.91, 1.13) | 0.94 (0.84, 1.05) | 0.38 | 0.99 (0.94, 1.05) |
| Multivariate model 12 | 1.00 | 0.91 (0.81, 1.01) | 0.92 (0.82, 1.03) | 0.90 (0.80, 1.00) | 0.81 (0.72, 0.91) | 0.001 | 0.94 (0.91, 0.98) |
| Multivariate model 23 | 1.00 | 0.93 (0.83, 1.04) | 0.99 (0.89, 1.11) | 1.02 (0.91, 1.15) | 0.99 (0.88, 1.12) | 0.64 | 1.01 (0.98, 1.05) |
| Multivariate model 34 | 1.00 | 0.98 (0.87, 1.10) | 1.07 (0.95, 1.20) | 1.12 (0.995, 1.27) | 1.13 (0.99, 1.29) | 0.01 | 1.07 (1.02, 1.11) |
| Dairy protein | |||||||
| Healthy ager/participants (n) | 693/9752 | 729/9753 | 799/9752 | 750/9753 | 750/9752 | ||
| Median intake (IQR) % energy | 1.7 (1.4, 2.0) | 2.6 (2.4, 2.8) | 3.4 (3.2, 3.6) | 4.3 (4.0, 4.6) | 5.9 (5.4, 6.8) | ||
| Age-adjusted model1 | 1.00 | 0.97 (0.87, 1.09) | 1.11 (0.99, 1.24) | 1.05 (0.94, 1.17) | 1.17 (1.05, 1.31) | 0.002 | 1.12 (1.06, 1.20) |
| Multivariate model 12 | 1.00 | 0.93 (0.83, 1.04) | 0.99 (0.89, 1.11) | 0.93 (0.83, 1.04) | 1.04 (0.92, 1.17) | 0.42 | 1.05 (0.98, 1.12) |
| Multivariate model 23 | 1.00 | 0.95 (0.85, 1.07) | 1.03 (0.91, 1.15) | 0.97 (0.86, 1.09) | 1.06 (0.94, 1.20) | 0.26 | 1.06 (0.99, 1.13) |
| Multivariate model 34 | 1.00 | 0.97 (0.87, 1.09) | 1.06 (0.95, 1.20) | 1.02 (0.91, 1.15) | 1.17 (1.03, 1.33) | 0.009 | 1.14 (1.06, 1.23) |
| Plant protein | |||||||
| Healthy ager/participants (n) | 611/9752 | 750/9753 | 726/9752 | 796/9753 | 838/9752 | ||
| Median intake (IQR) % energy | 3.7 (3.4, 4.0) | 4.4 (4.2, 4.5) | 4.8 (4.7, 4.9) | 5.2 (5.1, 5.4) | 6.0 (5.7, 6.4) | ||
| Age-adjusted model1 | 1.00 | 1.26 (1.13, 1.42) | 1.26 (1.12, 1.41) | 1.47 (1.31, 1.65) | 1.77 (1.58, 1.99) | <0.0001 | 1.82 (1.64, 2.03) |
| Multivariate model 12 | 1.00 | 1.12 (0.996, 1.26) | 1.10 (0.98, 1.24) | 1.22 (1.08, 1.37) | 1.42 (1.26, 1.60) | <0.0001 | 1.46 (1.30, 1.65) |
| Multivariate model 23 | 1.00 | 1.12 (0.99, 1.26) | 1.08 (0.96, 1.22) | 1.17 (1.03, 1.32) | 1.32 (1.16, 1.49) | <0.0001 | 1.31 (1.16, 1.48) |
| Multivariate model 34 | 1.00 | 1.15 (1.02, 1.29) | 1.12 (0.99, 1.27) | 1.23 (1.08, 1.40) | 1.41 (1.24, 1.62) | <0.0001 | 1.38 (1.24, 1.54) |
BMI, body mass index; CI, confidence interval; IQR, interquartile range; MET, metabolic equivalent; OR, odds ratio; SSB, sugar-sweetened beverage.
Logistic model adjusted for baseline age.
Multivariate logistic model 1 was adjusted for baseline age (continuous), race (White, other), education (registered nurse, bachelor, or graduate), marital status (married, other), postmenopausal hormone use (premenopausal; never, past user, current user), smoking status (never smoked; former smoker, 0.1–14.9, 15.0–29.9, >30 pack-y), alcohol intake (0, 0.1–4.9, 5.0–14.9, >15.0 g/d), physical activity (<3, 3–8.9, 9–17.9, 18–26.9, >27 MET/wk), baseline history of hypertension or hypercholesterolemia (yes, no), aspirin use (never, past, current), multivitamin use (yes, no), SSB intake, and total energy intake (kcal/d, quintiles).
Multivariate model 2 included the covariates in multivariate model 1 and was additionally adjusted for BMI (averaged 1984 and 1986; <22.5, 22.5–24.9, 25.0–27.5, 27.5–30.0, 30.0–34.9, >35.0).
Multivariate model 3 included covariates in multivariate model 2 with additional mutual adjustment of animal and plant protein. The models for dairy protein were adjusted for plant protein and other animal protein (nondairy protein).
P-trend was calculated by assigning median values to each quintile and was treated as a continuous variable.