[Influence of the aging process on body composition of the aged: the SENECA study in Spain]

The maintenance of an adequate proportion of muscular mass in aging, is critical for the quality of life of elderly people. In the face of the lack of longitudinal data, the semi-longitudinal SENECA (Survey in Europe on Nutrition and the Elderly, a Concerted Action) study was proposed, with the aim, among others, of analyzing the influence of the aging process on the body composition. In this study, the results are presented which correspond to the changes in body composition seen between the baseline study and the follow up period (1989-1993), in the participating Spanish population, which was randomly selected, and whose ages were between 70 and 80 years. There is also an analysis of the relation existing in 1993, between different anthropometric measurements and the functionality evaluated objectively by means of the physical and functional capacity test (PPT). Using a standardized methodology, the following were measured: size, breadth, weight, biceps and triceps fold, and the circumference of the waist, hips, and the upper arm. Based on these measurements, we calculated the body mass index (BMI), the waist/hip ratio, the muscular circumference of the arm, the fat mass, and the fat free mass. The longitudinal analysis between 1989-1993 showed a decrease for both sexes, in weight (-3.5 +/- 5.0 in men, and -3.4 +/- 4.0 kg in women: p < 0.001) and body circumferences; and also, in women, in the size and the triceps fold (-0.63 +/- 1.42 cm, p < 0.01, and -3.6 +/- 4.6 mm, p < 0.001, respectively). Consequently, the BMI (-1.4 +/- 1.8 for men and -1.4 +/- 1.8 kg/m2 in women, p < 0.01) decreased, while the waist/hip ratio did not change. A reduction of the fat free mass of -1.6 +/- 2.1 kg (p < 0.01) in men and -1.2 +/- 1.3 kg in women (p < 0.001), was observed, as well as a reduction of the body fat of -1.8 +/- 2.0% and -1.7 +/- 2.6% (p < 0.001), respectively. On the other hand, analyzing the anthropometric measurements of the follow up study, a positive association was detected for men, between the waist and hip measurements and the functionality measured by the PPT.