Table 3.
Hazard ratios (HRs) and 95% confidence intervals (95% CIs) for the risk of developing a low SMI according to tertiles of dairy protein intake at baseline.
| Variables | Men (n = 2096) | Women (n = 2316) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| T1 | T2 | T3 | p for Trend | p for Interaction d | T1 | T2 | T3 | p for Trend | p for Interaction | |
| Dairy protein intake a (g/day) | ||||||||||
| Cases (n)/person-months | 72/98,000 | 58/95,286 | 47/98,270 | 94/108,607 | 57/105,387 | 67/108,196 | ||||
| HR (95% CI) b | Reference | 0.79 (0.54,1.15) | 0.63 (0.42,0.94) | 0.029 | 0.004 | Reference | 0.78 (0.54,1.12) | 0.89 (0.63,1.28) | 0.667 | 0.402 |
| Higher protein intake c | ||||||||||
| Cases (n)/person-months | 17/29,342 | 22/43,739 | 31/61,273 | 19/35,229 | 23/53,131 | 37/76,721 | ||||
| HR (95% CI) | Reference | 0.67 (0.34,1.35) | 0.62 (0.32,1.19) | 0.943 | Reference | 0.84 (0.47,1.51) | 0.96 (0.57,1.64) | 0.636 | ||
| Lower protein intake | ||||||||||
| Cases (n)/person-months | 55/68,658 | 36/51,547 | 16/36,997 | 75/73,378 | 34/52,256 | 30/31,475 | ||||
| HR (95% CI) | Reference | 0.84 (0.53, 1.31) | 0.59 (0.35,0.99) | 0.036 | Reference | 0.72 (0.45,1.15) | 0.83 (0.50,1.36) | 0.743 | ||
| Dairy protein intake (% of protein) | ||||||||||
| Cases (n)/person-months | 75/96,885 | 57/97,370 | 45/97,301 | 91/106,787 | 59/107,590 | 68/107,813 | ||||
| HR (95% CI) | Reference | 0.72 (0.49,1.04) | 0.60 (0.41,0.89) | 0.017 | 0.007 | Reference | 0.80 (0.55,1.15) | 0.89 (0.63,1.26) | 0.640 | 0.439 |
| Higher protein intake | ||||||||||
| Cases (n)/person-months | 23/34,264 | 19/43,987 | 19/48,016 | 31/49,253 | 30/63,252 | 34/65,277 | ||||
| HR (95% CI) | Reference | 0.62 (0.32,1.19) | 0.58 (0.30,1.12) | 0.920 | Reference | 0.97 (0.56,1.69) | 1.05 (0.61,1.81) | 0.704 | ||
| Lower protein intake | ||||||||||
| Cases (n)/person-months | 52/62,621 | 38/53,383 | 26/49,285 | 60/57,534 | 29/44,338 | 34/42,536 | ||||
| HR (95% CI) | Reference | 0.78 (0.50,1.24) | 0.56 (0.34,0.92) | 0.010 | Reference | 0.69 (0.42,1.14) | 0.77 (0.49,1.23) | 0.458 | ||
| Milk protein intake (g/day) | ||||||||||
| Cases (n)/person-months | 81/107,429 | 55/94,575 | 41/89,552 | 98/114,331 | 46/83,691 | 74/124,168 | ||||
| HR (95% CI) | Reference | 0.86 (0.60,1.24) | 0.66 (0.45,0.99) | 0.048 | Reference | 0.78 (0.54,1.14) | 0.88 (0.63,1.13) | 0.641 | ||
| Yogurt protein intake (g/day) | ||||||||||
| Cases (n)/person-months | 80/123,787 | 42/54,157 | 55/113,612 | 55/113,612 | 86/120,518 | 46/66,918 | ||||
| HR (95% CI) | Reference | 1.28 (0.86,1.91) | 0.74 (0.51,1.07) | 0.037 | Reference | 0.90 (0.62,1.32) | 0.96 (0.69,1.33) | 0.930 | ||
a Protein intakes from milk, yogurt, and cheese. b Adjusted for baseline age (years), skeletal muscle mass at baseline, energy-adjusted protein intake (g/day), vitamins intake (sum of vitamin score: the first quartile received a score of 1; the second, third, and fourth quartiles received scores of 0), marital status (married/others), education level (≥college/others), income (≥3,000,000 KRW per month/other), smoking status (yes/no), alcohol consumption (yes/no), regular physical activity (METs-hours/day), self-perceived dental health status (poor/others), chronic diseases (yes/no), and residential area (urban/rural). c Higher protein intake: a total protein intake of ≥1.0 g/kg body weight/day; lower protein intake: a total protein intake of <1.0 g/kg body weight/day. d Test for interaction between protein intake and dairy protein intake.