Background & aims: We investigated whether protein intake (PI) is related to osteoporotic fractures (OP) in the elderly by analyzing vegetable protein intake (VPI), animal protein intake (API), and animal/vegetable protein intake ratio (AVR) and by calcium intake (CaI).
Methods: A 1:1 matched by age and sex case control study with 167 cases was carried out at the Hospital of Jaen (Spain). Cases were patients aged >= 65 years with a low-energy fracture. Controls were people without previous fractures. Diet was assessed by a food frequency questionnaire. Multivariable analyses were fitted using analysis of covariance (for comparison of adjusted means) and conditional logistic regression (estimating adjusted odds ratios [ORs]).
Results: The control-group showed a higher API (p = 0.046) even when CaI was <800 mg/day (p = 0.041). ORs for AVR were 0.68 (0.38-1.19) and 0.38 (0.15-0.98), respectively with a p for trend = 0.046. A PI<15% of the total energy intake showed an OR of 2.86 (1.10-7.43).
Conclusions: Patients with fracture history have lower API suggesting that high API reduce the occurrence of OP in elderly even if CaI is <800 mg/day. A PI<15% of total calories were associated with an increased risk of OP in elderly.