Background: Vitamin A deficiency (VAD) is a major public health problem in the developing world, leading to > 3 million eye-related problems in preschool children. Nearly 250 million children have subclinical VAD, resulting in a 23% increase in childhood mortality. Difficulties in obtaining samples to assess VAD have hampered the detection, intervention, and surveillance of VAD. The use of dried blood spots (DBS) could ameliorate many problems of vitamin A assessment. Objective: The objective of this study was to validate the use of retinol in DBS for vitamin A assessment by comparing it with venous and capillary serum retinol. Design: Venous and capillary blood specimens were obtained simultaneously from 20 healthy adult volunteers. From each blood specimen, both DBS and liquid serum were prepared (a total of 80 samples). All specimens were maintained at Ϫ70 ЊC until HPLC analysis. Results: The mean retinol concentrations in the 4 sample types were as follows: venous serum (2.02 ± 0.42 mol/L, or 58 ± 12 g/dL), capillary serum (2.06 ± 0.42 mol/L, or 59 ± 12 g/dL), venous DBS (2.06 ± 0.49 mol/L, or 59 ± 14 g/dL), and capillary DBS (2.09 ± 0.45 mol/L, or 60 ± 13 g/dL). Of the 6 possible 2-way combinations, the R 2 values ranged from 0.77 for capillary DBS versus venous DBS to 0.95 for venous serum versus capillary serum. Conclusions: DBS retinol measured by HPLC is comparable with serum retinol. Thus, it is possible to compare and combine blood retinol concentration data obtained from DBS with current and historic measurements in serum.
Anthropometry and body-composition measures, hematologic and biochemical measures of nutritional status, and helminthic infection were studied in the population of elderly persons (> or = 60 y of age) in a rural village in Guatemala that was 65% Mayan (indigenous) and 35% ladino (European). The population had low levels of literacy and formal education. The elderly persons were much shorter and lighter than reference populations. Anemia was present in 18% of the population, and riboflavin and vitamin B-12 deficiencies were detected in 70% and 38%, respectively. Both anthropometric and biochemical-hematologic variables were lower, on average, in the Mayan descendants than in the ladinos. When grouped by body mass index (BMI; in kg/m2), greater BMI signified higher values for almost all biochemical-hematologic measures. Sixty-five percent of the sampled population had mild-to-moderate Ascaris lumbricoides and Trichuris trichiura infections. The lifestyle in rural Guatemala is evolving, and the present findings provide insights into the evolution of nutritional status in the growing number of elderly in the countryside.
Aging is associated with diminished secretion of growth hormone and the major endogenous mediator of growth hormone action, insulin-like growth factor I (IGF-I). Aging is also associated with decreased physical activity. Alterations in body composition characteristic of the aging process (increased fat mass and decreased lean body mass) may be related to the decline in anabolic effects of IGF-I with aging, decreased physical activity, or both. Guatemalan women often maintain a high level of physical activity during aging. The purpose of this study was to determine whether IGF-I concentrations correlated with physical activity level (determined by standardized scoring of a self-report questionnaire) and body composition (determined by bioelectrical impedance analysis) in elderly Guatemalan women. In 112 women aged 20-87 y, we found a progressively lower serum IGF-I with age (r = -0.732). In subjects > 60 y of age, the self-reported activity level was associated with a lower percentage body fat (P < 0.001) but there was no significant relation between physical activity level and either lean body mass or IGF-I. We conclude that there is a significant age-related decline in serum IGF-I concentrations in Guatemalan women, similar to that observed in both men and women in the United States. An increased level of physical activity in the elderly Guatemalan population was associated with reduced body fat but did not modify the expected reduction in circulating IGF-I concentrations that occurs with aging.
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