[Validity of an equation based on anthropometry to estimate body fat in older adults]

A prediction equation to estimate body fat mass from skinfold thickness for healthy elderly was developed using a four compartmental (4C) model as criterion method. This study included 202 subjects = 60 y old. The measurements of total body water, bone mineral content and body density were included in the 4C model equation. Total sample was randomly partitioned. Sub-sample one was used to design the equations, which were applied in sub-sample two. Its accuracy and precision was evaluated by lineal regression analysis and the bias by Bland and Altman analysis and simple lineal regression. The best model included body mass, sex and the calf and triceps skinfolds thicknesses, with an R2, standard error of the estimate and Cp of 0.85, 3.2 and 3.2, respectively. When the equation was applied in sub-sample two, it was accurate and precise, it showed no significant deviation from the line of identity (the intercept was no significantly different from zero, P>0.05), and slope was different from cero (or similar to 1) (P<0.05). Fat mass by the equation accounted for 86% of the variability of the mean fat mass estimated by the 4C model, having a low standard error of the estimate (3.2 kg) and low pure error (3.1 kg). The new equation was accurate and precise as well as free of significant bias in men and women together and for separately. This equation can be a good option to estimate fat mass in elderly men and women with similar physical characteristics to subjects of this study, and it can be used in clinical and epidemiological studies in this growing group.

[Vitamin B12 and folate in non-institutionalized urban older people]

Vitamin B12 and folate deficiencies are the main nutritional determinants of hyperhomocysteinemia, which is an independent risk factor for cardiovascular diseases. There is scarce information about nutritional status on vitamin B12 and serum levels of folate in Mexican older people. The objective was to evaluate the nutritional status of vitamin B12 and folic acid concentration in non-institutionalized, urban elderly men and women subjects. One hundred volunteers over 60 years were included in this cross-sectional study. Serum levels of vitamin B12 and folate were measured. In addition some biochemical and anthropometric indicators were also evaluated. Considering serum values of vitamin, 30% had vitamin B12 deficiency, 52% normal status and 18% with high levels. None subjects had folic acid deficiency, by the contrary, a high proportion (62%) showed elevated levels in serum. There was an effect of sex on vitamin B12 status. Elderly men showed significantly lower levels of vitamin B12, and it was according with significant higher prevalence of vitamin B12 deficiency in this group as compared with the women group. The high proportion of vitamin B12 deficiency found in this study underline a possible public health problem and guarantee further survey-studies about vitamin B12 status and to explore causes and consequences of the deficiency. Finally, due the sample size and the design of the study, the results must be seen with caution and not try to generalize.