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Biomedical subjects

K M Koehler

Publications and source records attributed to K M Koehler.

At least 19 recordsLinked to original sources
PubMed1998

Epidemiology of sarcopenia among the elderly in New Mexico.

Muscle mass decreases with age, leading to "sarcopenia," or low relative muscle mass, in elderly people. Sarcopenia is believed to be associated with metabolic, physiologic, and functional impairments and disability. Methods of estimating the prevalence of sarcopenia and its associated risks in elderly populations are lacking. Data from a population-based survey of 883 elderly Hispanic and non-Hispanic white men and women living in New Mexico (the New Mexico Elder Health Survey, 1993-1995) were analyzed to develop a method for estimating the prevalence of sarcopenia. An anthropometric equation for predicting appendicular skeletal muscle mass was developed from a random subsample (n = 199) of participants and was extended to the total sample. Sarcopenia was defined as appendicular skeletal muscle mass (kg)/height2 (m2) being less than two standard deviations below the mean of a young reference group. Prevalences increased from 13-24% in persons under 70 years of age to >50% in persons over 80 years of age, and were slightly greater in Hispanics than in non-Hispanic whites. Sarcopenia was significantly associated with self-reported physical disability in both men and women, independent of ethnicity, age, morbidity, obesity, income, and health behaviors. This study provides some of the first estimates of the extent of the public health problem posed by sarcopenia.

Adult↗
PubMed1998

Helping elderly participants keep 3-day diet records in the New Mexico Aging Process Study.

Although verbal and written instructions on how to record dietary intake are commonly used in research, little information has been published describing instructional methods or materials. In the New Mexico Aging Process Study, a longitudinal study of nutrition and aging, participants keep a 3-day diet record each year. Classroom instruction and written materials are used in the study, and they were updated for use with Food Intake Analysis System (FIAS), version 2.3. This article describes the instructional methods and materials used to prepare elderly participants to keep accurate diet records; reports the development of a novel instructional tool, the food description flowcharts; and presents participants' opinions of the quality of the instruction and the usefulness of written materials. Included in the written materials were general instructions for recording food intake, examples of completed food intake and recipe forms, hints for eating out, and instructions for easy-to-use electronic scales. The flowcharts guide participants in accurately describing food intake while matching the coding requirements of FIAS. Fifty participants completed a written survey to evaluate the instructions and written materials. More than half of the respondents found the written materials to be very useful. All found the verbal instruction to be excellent or good. Nutritionists observed that records kept by participants who attended the class were generally complete and specific. The findings indicate that participants were satisfied with the instructions and written materials.

Aged↗
PubMed1998

Prevalences of type 2 diabetes, the insulin resistance syndrome, and coronary heart disease in an elderly, biethnic population.

OBJECTIVE: To compare the prevalences of type 2 diabetes, the various cardiovascular risk factors encompassing the insulin resistance syndrome (IRS), and coronary heart disease (CHD) in elderly Hispanics compared with non-Hispanic whites. RESEARCH DESIGN AND METHODS: Elderly Hispanics (n = 414) and non-Hispanic whites (n = 469), randomly selected from the Medicare rolls of Bernalillo County (Albuquerque, NM; age > or = 65 years), underwent a home interview followed by an interview/examination by a nurse-practitioner, nurse, and nutritionist that included an evaluation of glucose tolerance. Prevalences of total and central obesity, dyslipidemia, hypertension, and microalbuminuria also were determined. History of myocardial infarction, recent angina, and/or coronary bypass graft, and electrocardiograms (ECGs) were used to document CHD. RESULTS: Elderly Hispanics had twice the prevalence of type 2 diabetes compared with non-Hispanic whites, but the prevalence of impaired glucose tolerance was not increased in Hispanics. Mean serum fasting and 2-h post-glucola insulin concentrations, fasting insulin resistance indexes, and HbA1c were higher in Hispanics. Hispanics were shorter, weighed less, and had more total body and central obesity. The higher prevalences of dyslipidemia in Hispanics could be explained by a higher prevalence of diabetes. The prevalences of hypertension and CHD were not different for the two ethnic groups. CONCLUSIONS: Elderly Hispanics had twice the prevalence of diabetes and higher prevalences of cardiovascular risk factors associated with IRS. Prevalences of hypertension and CHD were similar in the two ethnic groups.

Aged↗
PubMed1997

Folate nutrition and older adults: challenges and opportunities.

Folate fortification of bread and grains has been directed to prevent neural tube birth defects. Research has also challenged previous concepts of folate nutritional status and suggested that folate may play a role in reducing the risk of vascular disease. Although folate status of many elderly people is adequate according to traditional, hematologic criteria, some elderly persons have elevated blood concentrations of the metabolite homocysteine, which indicates subclinical deficiency of folate or vitamin B-12. Higher homocysteine concentrations, even within the normal range, are associated with increased risk of vascular disease. Elderly people with better folate and vitamin B-12 status have lower homocysteine concentrations and may have lower risk for vascular disease. Although the new folate fortification rules provide the benefit of increasing folate in the food supply, they could be a risk for the elderly because excess folate intake can mask vitamin B-12 deficiency, thereby delaying diagnosis. Elderly people have a higher prevalence of vitamin B-12 deficiency as a result of absorption problems. Those deficient in vitamin B-12 should be treated to prevent irreversible neurologic damage. Modern approaches to screening the elderly include using higher cutoff points for serum vitamin B-12 and obtaining blood concentrations of the metabolite methylmalonic acid, which is elevated in deficiency of vitamin B-12 but not folate. To examine current folate intake and food sources, food frequency questionnaires were administered to 308 elderly volunteers aged 65 to 94 years. Mean (+/-standard error) folate intake from food was 299.6+/-5.8 microg/day. Supplements (median dose=400 microg/day) were consumed by 47% of participants. Only 3.2% of the sample had total folate intake greater than 1,000 microg/day, the recommended upper limit, and these were taking high-dose folate supplements (> or = 800 microg/day). Breakfast cereals provided 25.6% of folate intake; vegetables, 23.2%; fruit, 20.8%; refined breads/grains, 6.7%; dark bread, 5.0%; legumes/nuts, 5.9%; dairy products, 5.8%; meat/poultry/fish/eggs, 5.1%; other, 1.9%. Mean folate intake would increase 16.5% if enriched bread and grains were fortified. Such fortification could help some persons to lower serum homocysteine concentration and vascular disease risk. Dietitians should be aware of modern protocols for screening the elderly for vitamin B-12 deficiency.

Aged↗
PubMed1997

Changes in nutritional status and patterns of morbidity among free-living elderly persons: a 10-year longitudinal study.

Nutritional intake appears to be an important factor contributing to aging. In the present study we describe changes in physical health related to nutritional intake among elderly persons in a 10-y longitudinal study. Among 304 healthy elderly participants (median age 72 y on entry into the study in 1980), 97 (34.2%) are still in good health 10 y later in 1990, 74 (26.5%) have become frail or sick, 54 (19.1%) have died, and 57 (20.1%) have dropped out of the study. Women with lower or higher energy intakes (in 1980 and 1981) than the current Recommended Daily Allowance (RDA; between 25 and 30 kcal/kg) were more likely to become frail or sick or to die in 1990 than those with energy intake in the midrange (below RDA, odds ratio (OR) = 3.3, confidence interval (CI) = 1.2-8.6; above RDA, OR = 3.4, CI: 1.1-10.7). Moreover, women with protein intakes greater than the midrange of 0.8-1.2 g/kg of body weight (1.20-1.76 g/kg in 1980 and 1981) tended to have fewer health problems over the next 10 y than those with protein intakes < 0.8 g/kg, suggesting that the mean protein requirement in elderly adults is greater than that established by the 1985 joint World Health Organization/ FAO/UNU Expert Committee. Moreover, a decrease in energy intake was greater in elderly persons who died or dropped out of the study because of illness.

Aged↗
PubMed1997

Nutritional status and cognitive functioning in a normally aging sample: a 6-y reassessment.

Associations between nutritional status and cognitive performance were examined in 137 elderly (aged 66-90 y) community residents. Participants were well-educated, adequately nourished, and free of significant cognitive impairment. Performance on cognitive tests in 1986 was related to both past (1980) and concurrent (1986) nutritional status. Several significant associations (P < 0.05) were observed between cognition and concurrent vitamin status, including better abstraction performance with higher biochemical status and dietary intake of thiamine, riboflavin, niacin, and folate (rs = 0.19-0.29) and better visuospatial performance with higher plasma ascorbate (r = 0.22). Concurrent dietary protein in 1986 correlated significantly (rs = 0.25-0.26) with memory scores, and serum albumin or transferrin with memory, visuospatial, or abstraction scores (rs = 0.18-0.22). Higher past intake of vitamins E, A, B-6, and B-12 was related to better performance on visuospatial recall and/or abstraction tests (rs = 0.19-0.28). Use of self-selected vitamin supplements was associated with better performance on a difficult visuospatial test and an abstraction test. Although associations were relatively weak in this well-nourished and cognitively intact sample, the pattern of outcomes suggests some direction for further research on cognition-nutrition associations in aging.

Aged↗
PubMed1996

Structure and function of the zeta-globin upstream regulatory element.

The human zeta-globin promoter contains a strong positive regulatory element in the 5' flanking region, designated the zeta-globin upstream regulatory element (URE). In this study, we define the minimal sequences required for URE function and characterize the associated protein-DNA interactions. Deletion experiments show that the URE spans a 60 bp region located between 220 and 279 bp 5' to the transcription start site. Further subdivision of this region shows that multiple cis acting sequences are present. Electrophoretic mobility shift assays demonstrate that the erythroid transcription factor GATA-1 binds a site at -230, and Sp1 and an unidentified factor bind a CCACC site at -240. The unidentified CCACC factor is distinct from two other CCACC factors, EKLF and BKLF/TEF-2. A third complex contains a novel DNA-binding activity that interacts with a site in the -269 to -255 region, designated URE binding factor (URE-BF). This factor is present in K562 cells that express zeta-globin, but is absent in the OCIM1 cell line, a human erythroid cell line that does not express zeta-globin. URE-BF appears to interact with a GATA factor, since formation of the URE-BF complex can be prevented by the presence of unlabeled oligonucleotides containing GATA sites. Finally, increasing the distance from the -230 GATA site to the two upstream sites causes a progressive decrease in zeta-globin promoter activity. There is no indication of a requirement for GATA-1 to be on the same side of the DNA helix as the other upstream factors. These results show that zeta-globin promoter function is highly dependent on a 60 bp region to which at least three different factors bind. Two of these factors may represent DNA-binding proteins not previously identified as important for regulation of globin gene expression. It is likely that these factors interact physically to create a functional regulatory unit.

Cell Line↗
PubMed1996

Food preferences, practices, and cancer-related food and nutrition knowledge of southwestern American Indian youth.

BACKGROUND: Pathways to Health is a cancer prevention and health promotion curriculum for fifth- and seventh-grade Navajo and Pueblo students living in New Mexico. METHODS: A diet and nutrition questionnaire was administered to 1007 fifth- and seventh-grade students before beginning the Pathways to Health intervention. Sections of the questionnaire included listing favorite foods, frequency of intake of selected foods (e.g., "How often do you eat vegetables?"), targeted food practices (e.g., "When you eat chicken, do you eat the skin?"), and applied dietary fat and fiber knowledge questions. Descriptive analyses were generated by grade, gender, and tribe. RESULTS: Students' favorite foods were pizza, hamburgers, and tacos. Only 35.7% of students reported consuming the U.S. Dietary Guidelines recommendation of two or more daily servings of fruit, with only 19.3% reporting more than once-a-day intake of vegetables. The mean score (percent correct responses) to questions identifying common food sources of dietary fat and fiber, and other cancer-related nutrition knowledge questions, was 45.2% and 57.9% for fifth- and seventh-grade students, respectively. CONCLUSIONS: These and related data support the need for nutrition education interventions in this population that target essential cancer prevention skills and motivational information required to make positive dietary choices.

Adolescent↗
PubMed1996

Vitamin supplementation and other variables affecting serum homocysteine and methylmalonic acid concentrations in elderly men and women.

OBJECTIVE: An elevated serum concentration of the metabolite, homocysteine (Hcys): 1) can indicate folate or vitamin B12 deficiency, 2) is an independent risk factor for vascular disease. The metabolite, methylmalonic acid (MMA), is elevated in deficiency of vitamin B12, but not folate. The purpose of this study was to determine the effect of self-selected vitamin supplementation and other variables on serum Hcys and MMA concentrations in elderly men and women. METHODS: Serum concentrations of Hcys, MMA, folate and vitamin B12 were measured for elderly volunteers, age 68-96 years, and compared for those consuming (26 men, 25 women) and not consuming (24 men, 25 women) self-selected vitamin supplements. RESULTS: Compared with the nonsupplemented group, the supplemented group had lower mean serum MMA (208 +/- 162 vs. 241 +/- 98 nmol/L [+/- SD]) and Hcys (9.5 +/- 2.6 vs. 11.2 +/- 2.7 mumol/L); and higher serum vitamin B12 (391 +/- 174 vs 292 +/- 107 pmol/L), and serum folate (46 +/- 15 vs. 24 +/- 10 nmol/L) p < 0.05. Among all 100 subjects, the prevalence of serum vitamin B12 < 221 pmol/L (300 pg/mL) was 18; MMA > 271 nmol/L, 16; Hcys > 16.2 mumol/L, 3; folate < 5.0 nmol/L, none. Based on serum vitamin B12 < 221 nmol/L with elevated serum MMA, vitamin B12 deficiency was probable in seven subjects, of whom two were supplemented. All three subjects with elevated serum Hcys had elevated serum MMA as well, suggesting vitamin B12 deficiency or renal insufficiency. A stepwise linear regression model for serum Hcys explained 61.7% of the variance, and included (in order) serum creatinine, folate, vitamin B12, albumin, age and body mass index (BMI). A model with serum MMA replacing serum vitamin B12 explained 64.1% of the variance in serum Hcys. Folate did not enter the model for supplemented subjects, supporting a "threshold effect": serum Hcys was inversely related to serum folate at lower serum folate (nonsupplemented subjects), but at higher serum folate (supplemented subjects), the relationship was flat. In supplemented subjects, serum Hcys was still related to vitamin B12 status, confirming that tissue deficiency of the vitamin was present. CONCLUSIONS: Results showed potential usefulness of serum MMA and Hcys in identifying subclinical or tissue deficiency of vitamin B12. Clinicians should be aware of the risk of vitamin B12 deficiency in older people and of current screening algorithms using serum metabolites. These elderly volunteers had generally good folate status; nevertheless, some subjects seemed likely to benefit from an improvement in folate status that would reduce their serum Hcys within the normal range. The role of serum creatinine in the normal range in predicting serum Hcys, a vascular disease risk factor, remains unexplained.

Aged↗
PubMed1996

Associations of fat and muscle masses with bone mineral in elderly men and women.

Associations of fat and muscle masses with bone mineral status were studied in 301 men and women aged > or = 65 y. Bone mineral and soft tissue composition were estimated by using dual-energy X-ray absorptiometry. Univariate correlations suggested that muscle is associated more closely than fat with bone mineral content (BMC) as well as with bone mineral density (BMD) in men. In women, however, correlations of BMC with muscle were only slightly greater than those with fat and correlations with BMD were consistently greater with fat than with muscle. This suggests that correlations of BMC with muscle are influenced by bone and body size, especially in women. A multiple-regression model was developed that adjusts BMC for bone area, knee height, age, and the independent effects of fat and muscle. In men, muscle remained more closely associated with adjusted BMC than with fat. In women, fat mass was associated significantly with BMC but muscle mass was not. The exception was for women taking estrogen, in whom neither fat nor muscle was associated significantly with adjusted BMC. This study suggests that body fatness may be more important than muscle in maintaining bone mineral in elderly women not taking estrogen.

Absorptiometry, Photon↗
PubMed1996

Serum albumin is associated with skeletal muscle in elderly men and women.

Serum albumin concentrations decrease with age and values < 38 g/L are associated with increased morbidity, mortality, and disability in the elderly. It is not clear to what extent the decreases are associated independently with changes in metabolism, dietary intake, physical activity, morbidity, or body composition. We examined associations of serum albumin with age, protein and energy intakes, physical activity, morbidity, and muscle mass in 275 men and women aged 60-95 y. Serum albumin was measured with the bromcresol green procedure. Usual dietary intake and physical activity were quantified through questionnaires. Morbidity was ascertained from medical history, questionnaire, and examination. Muscle mass was estimated from dual-energy X-ray absorptiometry. In multivariate analyses, serum albumin was associated significantly with muscle mass after age, protein intake, physical activity, and comorbidity were controlled for in men and women. This study suggests that decreases with age in serum albumin concentrations are associated with muscle loss (sarcopenia) in the elderly. This association is independent of other factors that may affect muscle mass and albumin concentration. We suggest that the increased risk of disability with low serum albumin concentrations observed in the elderly may actually reflect an association with sarcopenia.

Aged↗
PubMed1995

Identification of a major positive regulatory element located 5' to the human zeta-globin gene.

The function of the zeta-globin promoter was studied using a series of zeta-globin promoter deletion constructs to drive luciferase expression in transiently transfected human erythroleukemia cells. The promoters were used without enhancers, or with enhancers derived from the beta-globin locus control region and the alpha-globin HS-40 enhancer. When transfected into K562 cells, which express zeta-globin, comparable amounts of activity were obtained from the -557 and -417 zeta-luciferase constructs and the alpha-luciferase constructs when no enhancers or the alpha-globin locus enhancers were used. When the constructs were transfected into OCIM1 cells, which do not express zeta-globin, the zeta-globin promoters were at best 20% as active as the alpha-globin promoters. When sequences from -417 to -207 5' to the zeta-globin mRNA cap site were deleted, up to 95% of the zeta-globin promoter activity was lost in K562 cells. Reinsertion of these sequences into zeta-luciferase constructs missing the -417 to -207 region showed that the sequences lack classical enhancer activity. Point mutation of a GATA-1 site at -230 reduced promoter activity by 37%. Point mutation of a CCACC site at -240 had no effect. Electrophoretic mobility shift assays indicated that the -230 GATA-1 site has a relatively low affinity for GATA-1. These experiments show the presence of a strong positive-acting element, located between -417 and -207 bp 5' to the zeta-globin mRNA cap site, is necessary for high-level promoter activity in K562 cells. This element requires GATA-1 and additional unknown factors for maximal activity.

Base Sequence↗
PubMed1995

Iron stores and iron absorption: effects of repeated blood donations.

We assessed changes in iron stores and iron absorption after repeat blood donations using a combination of biochemical measures of iron status: ferritin, hemoglobin, and transferrin saturation. Thirty-six volunteers with a mean (+/- SD) age of 67.7 +/- 3.7 y donated an average of 15 units of blood over 3.5 y. Initial iron stores were 12.45 +/- 3.09 mg/kg for men and 12.53 +/- 3.24 mg/kg for women. Of the 20 men and 16 women who completed the study, 6 men and 10 women were taking a self-selected supplement providing approximately 20 mg Fe/d. Dietary iron intake was determined to be approximately 20 mg/d for men and approximately 18 mg/d for women. Decreases in iron stores in supplemented men were not significantly different from those in nonsupplemented men: 9.52 +/- 2.57 and 11.31 +/- 2.74 mg/kg, respectively. Nonsupplemented women showed a significantly (P < 0.05) greater decline in iron stores than did supplemented women: 13.09 +/- 2.46 and 10.60 +/- 4.15 mg/kg, respectively. Mean maximal iron absorption was approximately 4.10 mg/d for men and approximately 3.55 mg/d for women regardless of iron intake.

Absorption↗
PubMed1995

Cross-sectional age differences in body composition in persons 60+ years of age.

BACKGROUND: There is little information for age differences in body composition in elderly people > 65 years of age, especially for those > 80 years. As the proportion of people older than 65 years is expected to nearly double during the next few decades, this information is needed. METHODS: Age differences in body composition and anthropometry were examined in 316 men and women aged 60 to 95 years. Multiple components of body composition were quantified using dual energy X-ray absorptiometry and isotope dilution methods, and expressed in molecular and cellular models. Analysis of variance was used to test for differences between age groups 60 to 70, 71 to 80, and > 80 years in each sex. Body composition components were regressed on age, controlling for knee height, fat-free mass, or total body fat. Age-adjusted correlations were calculated with anthropometric variables. RESULTS: Fat-free mass (FFM), body cell mass (BCM), and appendicular skeletal muscle (ASM) decreased with age in both sexes. ASM decreased relative to FFM in both the men and the women, while BCM decreased relative to FFM in the women only. Total fat mass and percent body fat decreased with age in the women, but not in the men. Body fat distribution did not appear to change with age. Anthropometric indices, muscle area and waist/hip ratio, had low correlations with muscle mass and fat distribution. CONCLUSIONS: "Sarcopenia," or muscle loss, continues to occur into old age, and may have significant impacts on physical function and health status. New anthropometric techniques are needed for assessing muscle loss with age.

Adipose Tissue↗
PubMed1993

Energy restriction reduces metabolic rate in adult male Fisher-344 rats.

Energy restriction, without malnutrition, prolongs the maximum life span of laboratory rodents. A reduction in metabolic rate has been proposed as a potential mechanism for increased longevity. The present study examines changes in metabolic rate of adult rats after a 6-wk period of energy restriction. Two groups (n = 6) of 6-mo-old male Fisher-344 rats were studied. Restricted rats were pair-fed a diet equivalent in vitamins and minerals but restricted to 60% of energy consumed by rats eating ad libitum. Average and basal metabolic rates were measured by direct calorimetry over a 24-h period without food. Fat mass and lean body mass were determined by NMR spectroscopy. After 6 wk of restriction, when expressed per kilogram of lean body mass the average metabolic rate was reduced by 14% and basal metabolic rate by 12% compared with the ad libitum diet rats (P < or = 0.01). Reduction of metabolic rate did not seem to be a transient effect of chronic energy restriction in mature rats.

Animals↗