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Original Research Communication |
1 From the Diet Assessment Center, Nutrition Department, Pennsylvania State University, University Park, PA (JHL, HS-W, and DCM); the Center for Human Nutrition, Vanderbilt University Medical Center (GLJ and JMF), Nashville, TN; and the High Risk Obesity Clinics, Geisinger Medical Center, Danville, PA (CDS).
2 Supported by the US Department of Agriculture, Agricultural Research Service under agreement #58-1950-1-137; VA Tennessee Valley GRECC; and NIH DK 26657. Additional support provided through a National Institute on Aging traineeship. 3 Reprints not available. Address correspondence to JH Ledikwe, 5 Henderson Building, Pennsylvania State University, University Park, PA 16801. E-mail: mvh111{at}psu.edu.
| ABSTRACT |
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Objective: This study investigated sex-associated differences in nutritional risk among community-dwelling, rural older adults and determined whether weight status [body mass index (BMI; in kg/m2) and waist circumference] was related to other measures of nutritional risk.
Design: This cross-sectional study explored relations between weight status and nutritional risk, which was determined on the basis of the Level II Screen, overall diet quality, nutrient intakes, and plasma biomarkers.
Results: Of the 179 subjects, 44% were overweight (BMI 2529.9) and 35% were obese (BMI > 30). There were few differences in nutrient intakes between older men and women after we controlled for energy intake. In women, BMI was directly associated with multiple additional nutritional risk indicators, including the number of Level II items (r = 0.30), intakes of fat (r = 0.26) and saturated fat (r = 0.21), and homocysteine concentration (r = 0.25). Weight status in women was inversely associated with intakes of carbohydrates (r = -0.25), fiber (r = -0.35), folate (r = -0.24), magnesium (r = -0.29), iron (r = -0.22), and zinc (r = -0.23); Healthy Eating Index scores (r = -0.22); and plasma pyridoxal 5' phosphate (r = -0.30). Associations with waist circumference were similar. In men, weight status was associated only with plasma cobalamin (r = -0.33 for BMI) and pyridoxal 5' phosphate (r = -0.24 for waist circumference).
Conclusions: Overweight and obese older women, particularly those living alone, may be at greater nutritional risk than are men with a high BMI. Targeted nutritional intervention emphasizing nutrient-dense food choices to improve dietary patterns may be warranted.
Key Words: Nutritional risk Nutrition Screening Initiative Level II Screen rural aging elderly obesity
| INTRODUCTION |
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Although high body weights are a prevalent nutritional risk factor in older adults (1214), it is unclear from the literature how obesity is associated with other nutritional risk indicators. Weight status was found to be associated with several plasma biomarkers (18, 19) and functional status (2); however, studies investigating how weight relates to dietary components have been limited in scope, focusing mostly on macronutrients and including subjects of mixed ages (20, 21). A comprehensive study with multiple measures of nutritional risk is needed in older adults. Sex should be considered when determining how weight status relates to other nutritional risk indicators, because sex-associated differences in various nutritional risk factors have been noted. These risk factors include weight (1), sociodemographic factors (12), oral health (12), functional status (2), and nutrient status (12, 22, 23).
The objectives of this study were to identify sex-associated differences in nutritional risk among community-dwelling, rural older adults and to determine whether weight status, as assessed with body mass index (BMI) and waist circumference, is related to other measures of nutritional risk. Rural older adults have been found particularly vulnerable to nutritional inadequacies (24). Contributing factors may include social and geographic isolation, limited access to transportation, and limited availability of nutrition-related services. A better understanding of the associations between potentially modifiable nutritional risk factors, such as weight status and diet, may guide interventions to decrease healthcare resource use and to improve the quality of life for rural older adults.
| SUBJECTS AND METHODS |
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65 y (14). All GRAS participants were enrolled in a Medicare risk program administered through the Geisinger Health Care System, a not-for-profit health maintenance organization that provides services for many persons residing in small towns with populations of
2499 (25). Study procedures were approved by the Geisinger and Pennsylvania State University human investigation review boards.
Letters introducing the study were mailed to 944 individuals selected from the first 9989 GRAS participants by using a computer-generated random scheme. Inclusion criteria included having a phone, living in the community, and consenting to a home visit. Up to 3 attempts were made to reach each prospective participant by telephone (26). Of the 797 individuals reached by telephone, 210 provided written informed consent to participate and were each scheduled for a home visit; 10 withdrew before the home visit. During the home visit, the Mini Mental State Examination (27) and the Geriatric Depression Scale (28) were used for exclusion purposes. Of the 200 potential participants, 1 was excluded because of poor cognitive function (Mini Mental State Examination score
23), 6 were excluded because of depression (Geriatric Depression Scale score
6), 11 withdrew, and 1 died. The GRAS subset did not differ significantly from the large GRAS cohort regarding sex, age, demographics, anthropometric measures, and serum cholesterol and albumin. Individuals in the GRAS subset were less likely than were those in the large GRAS cohort to report having a poor appetite and needing assistance with bathing, traveling, and food preparation. However, these differences were quite small and were most likely a result of the tendency for individuals with more limitations to be less interested in research studies.
Demographics and health status
Demographic data collected during the home visit included age, sex, education level achieved, and marital status. The presence or absence of > 30 different health conditions was ascertained by asking subjects if a physician had ever told them they had each condition, including various cardiovascular diseases, gastrointestinal diseases, musculoskeletal diseases, and cancers. Data were collected on the use of medications and dietary supplements.
Anthropometric measures
Height and weight measurements were completed during the home visit by trained research dietitians using a portable digital scale (UC300; A & D Engineering, Mitpiltas, CA) and a stadiometer (Infant/Child/Adult Height Measuring Board; Shorr Productions, Olney, MD). BMI was calculated as weight (kg)/height (m)2. Waist circumference was measured with a flexible, nonelastic measuring tape. Standardized procedures developed on the basis of the National Health and Nutrition Examination Survey were followed (29). Every twentieth participant was measured by both research dietitians to monitor interrater reliability.
Level II Nutrition Screen
The Level II Nutrition Screen (LII) is 1 of 3 tools developed by the Nutrition Screening Initiative, a collaborative effort of the American Dietetic Association, the American Academy of Family Practitioners, and the National Council on the Aging Inc to aid in the evaluation of the nutritional status of older persons (17). The Nutrition Screening Initiative tools include the DETERMINE checklist, which is a brief public-awareness tool; the Level I Nutrition Screen, which is a risk-assessment tool intended for use by health care professionals; and the more comprehensive LII, which was developed for use by medical and nutrition professionals. A modified LII was administered by telephone, as described previously (5, 14, 30). It consisted of 42 items pertaining to use of medications, oral health, eating habits, living environment, and functional status (activities of daily living and independent activities of daily living). Skinfold-thickness and arm-circumference measures on the Nutrition Screening Initiative LII were not included because of the method of administration by telephone. The single question "Do you feel depressed?" was substituted for formal testing of mental and cognitive status because the Geriatric Depression Scale and Mini Mental State Examination had been used for exclusion criteria.
Trained interviewers from the Penn State Diet Assessment Center collected the data using an electronic version of the survey tool created in MICROSOFT ACCESS, version 97 (Microsoft Corp, Redmond, WA) for real-time data entry during the interview. The LII also includes laboratory data, with thresholds for albumin and cholesterol. Plasma samples collected at the home visit were analyzed for these biomarkers and compared with Nutrition Screening Initiative recommendations (17). No standardized scoring algorithm is available for the LII. For the purpose of this analysis, the number of unfavorable LII items was summed for each participant to create an LII summary score. The LII does include self-reported height and weight, with BMI values > 27 considered a risk item; however, self-reported and measured BMI were excluded from the summary score because comparisons were made between LII score and weight status.
Dietary intake and diet quality
After the home visit, the staff of the Penn State Diet Assessment Center collected 5 random, 24-h dietary recalls by telephone from each participant at 2-mo intervals. For each participant, data were collected on 3 weekdays and 2 weekend days. The NUTRITION DATA SYSTEM software, food database version 12A, nutrient database version 28 (Nutrition Coordinating Center, University of Minnesota, Minneapolis) was used for data collection and analysis with a multiple-pass technique (31) to facilitate recall. Two-dimensional visuals of cups, spoons, bowls, and various shapes (32) were used by participants and interviewers to assist with portion-size estimation. The prevalence of inadequate nutrient intakes was determined by using the estimated average requirement cutoff method (33) for nutrients with an established estimated average requirement (3437). For other nutrients, mean intakes were compared with Adequate Intake recommendations (33). Nutrient intake estimates reflect the foods consumed and do not include intake from supplements.
Healthy Eating Index (HEI) scores, which reflect overall diet quality, were calculated (38). Ten components including 5 food groups (grains, vegetables, fruit, milk, and meat), 4 nutrients (sodium, cholesterol, total fat, and saturated fat), and a measure of dietary variety were each assigned a score ranging from 0 to 10 on the basis of the criteria set by the US Department of Agriculture, for a total possible score of 100 (38). The HEI does not include an energy component. The intake of foods from the different food groups was determined on the basis of methodology described elsewhere (39).
Biomarkers of nutrient status
A venous blood sample (30.5 mL) was obtained from each participant during the home visit and was placed on ice for transport. The serum was separated by centrifugation (3000 x g for 12 min at 28 °C) and stored at -70 °C. The following laboratory analyses were conducted at Tufts University. Plasma concentrations of folate and cobalamin (vitamin B-12) were measured by using competitive protein-binding assays (BioRad, Hercules, CA). Pyridoxal 5' phosphate (PLP) was measured with a radioenzymatic assay (40); homocysteine was determined with HPLC (41), and 25-hydroxyvitamin D was measured with a competitive protein-binding assay (42). Serum concentrations of albumin, prealbumin, C-reactive protein, and cholesterol were determined at Geisinger Medical Center by using rate nephrolometry (Beckman Reagents Array 360; Beckman Instruments, Brea, CA). Unfavorable values were designated as follows: plasma folate < 6.8 nmol/L (43), PLP
18.1 nmol/L (44), plasma vitamin B-12 < 258 pmol/L (43), 25-hydroxyvitamin D < 12.0 nmol/L (43), homocysteine > 14.0 µmol/L (44), C-reactive protein < 10.0 mg/L (18), prealbumin < 170 mg/L, plasma albumin < 35.0 g/L (17), and cholesterol < 4.14 or > 6.21 mmol/L (17).
Statistical analyses
The data were analyzed with SAS, version 8 (SAS Institute Inc, Cary, NC). Measured BMI values were standardized to assess for potential outliers with z scores > 3.29 (45); 2 cases with raw BMI values > 53 fit this criterion and were excluded. Categorical variables were summarized by using frequencies and percentages. Means and standard deviations were calculated for continuous variables and normality was assessed. Variables not normally distributed were log transformed before analysis. To assess differences between men and women, chi-square analysis and analysis of variance were performed on categorical variables and continuous variables, respectively. Pearsons product-moment correlation coefficients were used to determine the association between measured BMI and waist circumference and the associations between the biomarker values. Logistic regression was used to determine whether individual LII items were associated with measured BMI. Associations between weight status and nutritional risk were assessed by using partial Pearsons product-moment correlation coefficients adjusted for energy intake, age, tobacco use, and alcohol use.
| RESULTS |
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BMI values ranged from 20.7 to 41.6 (excluding 2 persons with BMI > 53). On the basis of the NIH guidelines (46), none of the subjects were underweight (BMI < 18.5), 21% were normal weight (BMI 18.524.9), and 44% were overweight (BMI 2529.9). Another 28% were classified as being in obesity category I (BMI 3034.9), 6% were in obesity category II (BMI 3539.9), and 1% were in obesity category III (BMI
40). The data appear to follow the same pattern that was found in the larger GRAS cohort, in which women were more likely than men to have low or high BMI values (2, 5, 14); however, the percentages of men and women in the 5 BMI categories did not differ significantly, most likely because of small cell sizes in the higher BMI categories. On average, men had a higher waist circumference than did women, but there was no significant difference between men and women in the percentages of participants with waist circumferences above the NIH risk cutoffs (102 cm for men and 88 cm for women) (46). BMI was highly correlated with waist circumference (r = 0.73, P < 0.0001).
Nutritional risk and nutritional status by sex
Nutritional risk
The mean LII score was 6.3 for both men and women (Table 2
). The most prevalent risk items were using
3 medications and supplements, self-reported BMI > 27, age > 75 y, living alone, eating alone, serum cholesterol > 240 mg/dL, and limited spending on food. Women were more likely than were men to live alone, eat alone, spend a limited amount of money on food, and report having any functional limitation.
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The majority of participants had inadequate intakes of folate (79%), magnesium (82%), and vitamin E (91%); women were more likely than were men to have an inadequate intake of folate. Inadequate intakes of zinc (44%) and vitamin B-6 (32%) were common. Mean intakes of vitamin B-12 were above the Adequate Intake values, suggesting a low prevalence of inadequate intakes. Mean intakes of vitamin D and calcium were substantially less than the Adequate Intake (33).
HEI scores were 68.3 and 70.8 for men and women, respectively. The US Department of Agriculture has proposed that scores of
80 indicate diets that need improvement. The majority of participants (88%) fell into this category.
Nutritional status: plasma biomarkers
There were no significant differences between men and women in plasma biomarker values (Table 3
). Three percent of the participants had PLP concentrations
18.1 nmol/L and 25% had low plasma cobalamin concentrations. Approximately 10% of the participants had elevated concentrations of homocysteine and C-reactive protein. Homocysteine concentrations were inversely correlated with plasma PLP (r = -0.25, P < 0.002), folate (r = 0.24, P < 0.002), and cobalamin (r = -0.36, P < 0.0001). High C-reactive protein concentrations were associated with low PLP (r = -0.15, P < 0.05) and high folate (r = 0.18, P < 0.05) concentrations.
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10 pounds in the past 6 mo, and several individual limitations in activities of daily living and independent activities of daily living (data not shown). For men, elevated BMI was associated with not having a self-reported weight gain of
10 pounds in the past 6 mo and with not following a special diet (data not shown). For men, there was no association between BMI or waist circumference and intakes of any nutrients. However, for women, there were significant correlations for several macronutrients and micronutrients. BMI and waist circumference were both positively associated with fat and saturated fat intakes and negatively associated with intakes of carbohydrate, fiber, folate, magnesium, iron, and zinc and the HEI score.
For men, high BMI was associated with low plasma cobalamin concentrations, whereas high waist circumference was associated with low plasma PLP. For women, BMI and waist circumference were both negatively associated with plasma PLP and positively associated with plasma homocysteine values.
| DISCUSSION |
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Many of the participants had poor-quality diets, as indicated by the results of the multidimensional HEI and by intakes of individual nutrients that were below current recommendations. These findings are consistent with the results of other studies (12, 22, 23) and nationwide data (47). Most notable were the low intakes of folate, vitamin B-6, vitamin D, calcium, magnesium, zinc, and vitamin E. Because the intake data were collected during the fortification period, the nutrient database may not have reflected true folate intakes. Inadequate intakes of any of these nutrients pose potential public health consequences by increasing the risk of vascular diseases (48), impaired immune function (49), and cognitive status (50). Furthermore, recent associations between poor diet quality and undesirable plasma biomarkers (51) and mortality (15) emphasize the importance of dietary patterns to health and longevity.
The assessed dietary risk in this population may have been inflated by underreporting (52), which can be as high as 30% of intake (53) and is more common in older adults and overweight individuals (54). However, plasma biomarkers did provide evidence of nutritional inadequacy because cobalamin values were low for almost 25% of the sample and several subjects had low PLP values. Given the associations of these biomarkers with increased homocysteine values in this study and others (16, 44), low concentrations of PLP and cobalamin could have serious consequences.
Particularly notable in this study are the sex differences in how body size relates to other nutritional risk indicators, even though there were few differences in nutrient intakes between men and women. In women, elevated BMI or waist circumference was associated with multiple additional nutritional risk indicators, including LII items, nutrient intakes, HEI scores, and plasma biomarkers. In men, however, weight status was only associated with plasma cobalamin and PLP.
The lower nutrient intakes and HEI scores with higher BMI or waist circumference indicate that older overweight and obese women are less likely than are overweight and obese men to meet nutrient requirements and have healthy eating patterns. Given that diet patterns rich in nutrient-dense foods have beneficial effects on homocysteine and blood vitamins (55, 56), it is plausible that suboptimal nutrient intakes contributed to the unfavorable associations of weight status with homocysteine and plasma PLP in women.
Sex differences in the associations between weight status and health have been reported by others. Measures of body fatness were associated with blood pressure in women only (57). Friedmann et al (2) reported that BMI was more strongly correlated with functional limitations in women than in men. Previous studies investigating the correlations between diet and body composition also found that adiposity was positively associated with dietary fat intake (20, 21) and inversely associated with fiber intake (21). Although these relations did not differ by sex, the studies were not conducted solely in older adults. Because the correlation between weight status and fiber intake was higher than were other correlations with weight status in women, fiber intake may play an important role in attaining and maintaining a healthy weight. Further research is warranted regarding the relations between fiber intake and weight status.
The source of the discrepancy between men and women regarding how body size relates to other nutritional risk indicators is unclear. Social factors, especially living arrangements, may play a role. Older women were more likely than were older men to live alone, which was associated with higher BMI values. Furthermore, when controlling for energy intakes, women living alone reported lower intakes of several nutrients than did men living alone or women living with others. Other studies also indicated that living and eating alone influence diet quality (11, 51). A second explanation for the discrepancy between men and women is that the presence of functional limitations, which reportedly increase with BMI in older women (2, 5), may affect nutrient intakes and diet quality. A third explanation is a survivor effect in which the sex difference in mortality could lead men with multiple nutrition-related risk factors to die earlier than women with multiple risk factors. Also, because age is associated with nutritional risk, it is plausible that the obese women may have been older than the obese men; however, age was controlled for in the analyses and there was no sex difference in age. Finally, it is plausible that weight loss before the study could have obscured the relation between BMI and nutritional risk in men; a previous study found that the increased risk for coronary heart disease associated with BMI was masked by prior weight loss (58). However, in this study, there was no difference between the percentages of men and women who reported losing
10 pounds in the previous 6 mo.
The associations between weight status and other markers of nutritional risk are worrisome, given the growing prevalence of overweight and obesity among older adults. It is clear that high body weights are common among community-dwelling rural elders, and similar findings were reported in urban homebound elders (59). The prevalences of overweight and obesity were higher in the GRAS subset than in older subjects in the third National Health and Nutrition Examination Survey (1). Other studies also indicate that obesity is more prevalent in rural older adults than in nationally representative samples of older adults (2, 14, 60, 61). This study was unable to address any associations between underweight and other measures of nutritional risk because there were no subjects with a BMI < 18.5. Other studies also found that underweight was uncommon among community-dwelling older adults (2, 5, 14, 62). It is unclear whether the relations between weight status and nutritional risk in rural older women drawn from a Medicare health plan can be generalized to other populations of older persons. Given the cross-sectional nature of this study, further research is needed to assess the stability of the associations between weight status and other nutritional risk measures over time. Further work is also necessary to clarify how these associations are related to health and longevity through examination of quality of life as well as objective resource measures, such as hospital admissions and physician contacts.
Conclusions
Multiple measures indicate that this population is at nutritional risk. Overweight and obesity are prevalent among community-dwelling, rural older adults. Although there are few differences in nutrient intakes between older men and women after controlling for energy intake, high BMI is related to multiple additional nutritional risk factors in women. This finding suggests that overweight and obese older women, particularly those living alone, may be at greater nutritional risk than are men with high BMI values. These data indicate that overweight and obesity can be associated with inadequate intakes of desirable nutrients and unhealthy dietary patterns in rural older adults. Given that weight loss in older adults has been associated with functional decline (5), it may be more appropriate to suggest weight maintenance rather than weight loss; however, further work in this area is needed. It appears that overweight and obese women represent a nutritionally vulnerable group in need of targeted nutritional interventions to improve dietary patterns through increased consumption of nutrient-dense foods. Because older adults are a very heterogeneous group, further investigations are needed to discern the health consequences of different amounts of nutrient intake in obese older women. A better understanding of factors that are associated with adverse health outcomes, such as weight status and diet, may play a role in decreasing the use of health care services and improving the quality of life for older adults.
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| ACKNOWLEDGMENTS |
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All of the authors were involved in planning the study design. Overall study direction was by HS-W and GLJ. Dietary and screening data were collected under the supervision of HS-W and DCM. Biochemical and anthropometric data were collected under the supervision of GLJ, JMF, and CDS. Data analysis was the primary responsibility of JHL, who was also responsible for the first draft of the manuscript. All authors were closely involved in revisions and final approval. None of the authors have had any financial or personal interest in the organization that sponsored the research.
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