Relationship between plasma retinol and infectious diseases in the elderly. A case-control study

This study assessed the relationship between plasma retinol deficiency and infectious diseases. The plasma retinol, anthropometric (Body Mass Index, triceps skinfold thickness, mid-arm muscle circumference) and biological indices (proteins, albumin, transferrin, prealbumin, retinol binding protein) of protein-energy malnutrition of 63 patients with infectious diseases (ID) were compared to those of two control groups of similar age: 527 patients with other diseases (C1) and 92 healthy people (C2). Plasma retinol, albumin, transferrin and prealbumin were significantly lower in the ID group than in the C1 group. A lower body mass index was noted in men only. The ID and C1 groups had lower values for all indices (except for mid-arm muscle circumference). The ID group had lower albumin, transferrin, and prealbumin than the C1 group. The percentage of patients with plasma retinol below 300 microg/l was higher in the ID group (48.0% in men, 39% in women) than in the C1 group (25.0 and 21.5%); the odds ratio adjusted on age and sex equaled 2.46, 95% CI (1.39-4.37). It was lower than 2% in the C2 group. The results obtained with multiple regression analysis showed that, in the patients, the association between plasma retinol and infectious diseases remained significant when age, sex, anthropometric and biological indices were taken into account. Consequently, it is useful to check up the food intake habits of the elderly.