Table 2.
Association of Protein Intake With the Risk of Hip Fracture in Men and Women From the Framingham Offspring Cohort
| Hazard ratiob for tertiles of protein intake | ||||||||
|---|---|---|---|---|---|---|---|---|
| Total calcium intake < 800 mg/day,c n = 2124, n events = 29 | Total calcium intake ≥ 800 mg/day,c n = 1532, n events = 15 | |||||||
| Protein exposuresa | T1 ref) | T2 | T3 | p trend | T1 (ref) | T2 | T3 | p trend |
| Total protein (g/day), n events | 10 | 9 | 10 | — | 7 | 5 | 3 | — |
| Total protein (g/day) | 1.0 | 1.41 (0.56–3.56) | 2.02 (0.83–4.94) | .12 | 1.0 | 0.66 (0.20–2.20) | 0.30 (0.07–1.25) | .09 |
| Total protein (g/day)d | 1.0 | 1.46 (0.58–3.70) | 2.20 (0.88–5.54) | .09 | 1.0 | 0.70 (0.20–2.40) | 0.54 (0.12–1.30) | .38 |
| Animal protein (g/day), n events | 9 | 6 | 14 | 5 | 8 | 2 | — | |
| Animal protein (g/day)e | 1.0a | 0.94 (0.32–2.69)a b | 2.84 (1.20–6.74)b | .02 | 1.0a | 1.16 (0.33–3.90)a b | 0.15 (0.02–0.92)b | .04 |
| Animal protein (g/day)d e | 1.0a | 0.97 (0.33–2.78)a b | 3.17 (1.30–7.78)b | .01 | 1.0 | 1.51 (0.43–5.31) | 0.32 (0.05–2.08) | .33 |
| Plant protein (g/day), n events | 11 | 13 | 5 | 6 | 6 | 3 | ||
| Plant protein (g/day)e | 1.0 | 1.02 (0.43–2.40) | 0.56 (0.19–1.68) | .28 | 1.0 | 0.77 (0.23–2.59) | 0.24 (0.06–1.06) | .07 |
| Plant protein (g/day)d e | 1.0 | 1.10 (0.46–2.64) | 0.60 (0.20–1.85) | .34 | 1.0 | 0.59 (0.17–2.04) | 0.23 (0.05-1.03) | .06 |
| Animal/plant protein, n events | 11 | 4 | 14 | 5 | 7 | 3 | ||
| Animal/plant proteinf | 1.0 | 0.46 (0.14–1.48) | 1.86 (0.69–4.99) | .26 | 1.0 | 2.24 (0.66–7.56) | 1.20 (0.23–6.21) | .65 |
| Animal/plant proteind f | 1.0 | 0.45 (0.14–1.45) | 1.81 (0.68–4.86) | .29 | 1.0 | 2.50 (0.70–8.87) | 2.02 (0.37-11.05) | .32 |
Multivariate models adjusted for sex and menopause status (group 1: men; group 2: premenopausal women; group 3: postmenopausal women), age (years), weight at baseline (kg), height at baseline (m), physical activity index, intake of energy (MJ/day) and total vitamin D (IU/day), and smoking status (current versus former/never). Protein exposures were energy-adjusted residuals added to a constant, where the constant equals the nutrient intake for the mean energy intake of the study population.
Hazard ratio (HR) with different superscripts are significantly different from HR of tertile 1 at p < .05.
Range (median intake of dietary calcium) in subjects with <800 mg/day of calcium intake by tertiles of total protein intake (g/day): T1 = 109–799 (517) mg/day; T2 = 108–799 (525) mg/day; and T3 = 146–799 (578) mg/day. Range (median intake of dietary calcium) in subjects with ≥800 mg/day of calcium intake by tertiles of total protein intake (g/day): T1 = 188–2550 (920) mg/day; T2 = 199–2056 (950) mg/day; and T3 = 206–3283 (1096) mg/day.
Models were additionally adjusted for dietary calcium intake.
HRs for animal and plant protein intakes were estimated from the same model, adjusting for each other.
Models for animal/plant protein ratio were additionally adjusted for total protein intake.