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Association of Dietary Patterns With Albuminuria and Kidney Function Decline in Older White Women:
A Subgroup Analysis From the Nurses' Health Study - pdf attached
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Download the pdf here
from Jules: This study conducted in middle aged white women 30-55, average age 67, found that the western diet (red meats, refined grains (white rice, spaghetti, sweets, desserts) doubled the risk of more protein in the urine (microalbuminurea & increased risk of eGFR decline (kidney function). While the more healthy DASH diet (higher intake of fruits, vegetables, nuts, legumes, low-fat diary products, whole grains and low sodium intake was associated with a 50% decline in risk for eGFR decline (kidney function). Inflammation appears to be a link between poor diet and kidney function, in other words the western diet increases inflammation while the DASH diet reduces inflammation. Other studies have found similarly in men and in diverse racially and ethnically study patients. EXERCISE - although this study did not examine exercise, other studies find exercise reduces inflammation, improves cognitive function, improves metabolics (sugar, lipids) and improves sense of well-being.
American Journal of Kidney Diseases
Volume 57, Issue 2 , Pages 245-254, February 2011
.......In conclusion, a Western pattern diet was associated with a 2-fold higher OR for microalbuminuria and increased risk of rapid eGFR decline (≥3 mL/min/1.73 m2/y). A DASH-style diet was associated with an almost 50% declined risk of eGFR decline. Therefore, diets higher in fruits, vegetables, and whole grains, but lower in meat and sweets, may be protective against eGFR decline......Women in the highest quartile of the Western pattern had a significant 2-fold increased odds of having microalbuminuria and experiencing more rapid eGFR decline ≥3 mL/min/1.73 m2/y. Moreover, a DASH-style pattern appears to decline risk by >40% for eGFR decline ≥30% over 11 years.......We hypothesize that inflammation might be one possible pathophysiologic link between dietary patterns and microalbuminuria. A number of studies have reported significant direct associations between markers of inflammation and higher albuminuria"
"Female participants in the Nurses' Health Study.....Median age was 67 years, 97% were white, 54% had hypertension, and 23% had diabetes......Our data suggest that dietary patterns are associated with microalbuminuria and kidney function decrease in middle-aged and older women.......Study cohort included primarily older white women and generalizability of results would benefit from validation in nonwhites and men.....However, similar results in the analysis of dietary patterns and albuminuria in the ethnically diverse MESA cohort would suggest that the associations may not vary substantially by race or ethnicity.......An investigation in the MESA that included almost 5,000 ethnically diverse men and women similarly has reported that a dietary pattern rich in whole grains, fruit, and low-fat dairy foods was associated with lower urinary ACR (20% lower ACR across quintiles, P for trend = 0.004), whereas nondairy animal-based food intake was associated directly (11% higher ACR across quintiles, P for trend = 0.03).6 The MESA cohort also has reported that diets high in whole grains, fruits or vegetables, and fish are associated inversely with markers of inflammation, including CRP and soluble ICAM-1 levels, whereas a diet pattern high in fats and processed meats was associated directly with markers of inflammation, including CRP.34 Data from other cohorts provide external validation for our findings regarding diet patterns, inflammation, and albuminuria in the NHS cohort."
"prudent pattern, is characterized by higher intake of fruits, vegetables, whole grains, fish, and poultry. The second factor, which we called the Western pattern, is characterized by higher intake of processed and red meats, refined grains, sweets, and desserts....We also constructed the DASH score as previously detailed14, 15 (range, 8-40 points) based on food and nutrients emphasized or minimized in the DASH diet16 focusing on 8 components: high intake of fruits, vegetables, nuts, legumes, low-fat dairy products, and whole grains and low intake of sodium, sweetened beverages, and red and processed meats."
"Median age was 67 years, 97% were white, 54% had hypertension, and 23% had diabetes.....The 177 women (5.7%) who met the criterion for microalbuminuria (ACR, 25-355 μg/mg) were more likely to be older and have hypertension, diabetes, cardiovascular disease, higher BMI, and lower activity levels.....We hypothesize that inflammation might be one possible pathophysiologic link between dietary patterns and microalbuminuria. A number of studies have reported significant direct associations between markers of inflammation and higher albuminuria.......Our data suggest that dietary patterns are associated with microalbuminuria and kidney function decrease in middle-aged and older women. Women in the highest quartile of the Western pattern had a significant 2-fold increased odds of having microalbuminuria and experiencing more rapid eGFR decline ≥3 mL/min/1.73 m2/y. Moreover, a DASH-style pattern appears to decline risk by >40% for eGFR decline ≥30% over 11 years......An investigation in the MESA that included almost 5,000 ethnically diverse men and women similarly has reported that a dietary pattern rich in whole grains, fruit, and low-fat dairy foods was associated with lower urinary ACR (20% lower ACR across quintiles,......There are no published data for dietary patterns and eGFR decline, but recent investigations have suggested that markers of inflammation,35 including CRP,36 are associated with faster eGFR decline. .....We previously reported that higher dietary intake of animal fat was associated with the presence of microalbuminuria, whereas higher sodium intake was associated directly and higher beta-carotene intake was associated inversely with faster eGFR decline over 11 years.28 The present study provides additional information regarding decline in kidney function and dietary patterns that may be interpreted more easily by the general public......For example, in a recent publication from the National Health and Nutrition Examination Surveys 1999-2004, each 1-mg/dL increase in C-reactive protein (CRP) level was associated independently with a 1.02 (95% CI, 1.01-1.02; P = 0.0003) OR for the presence of microalbuminuria in this large nationally representative cohort.30 Furthermore, the highest tertile of ICAM-1 (inter-cellular adhesion molecule 1), a vascular endothelial transmembrane glycoprotein upregulated by inflammation, also previously has been associated independently with the development of incident sustained microalbuminuria (OR, 1.67; P for trend = 0.03) in patient with type 1 diabetes.31.....Previous work on dietary patterns and inflammation reported that the Western diet pattern showed significant direct correlations between CRP, ICAM-1, and VCAM-1 (vascular cell adhesion molecule 1) levels in multivariable models that included adjustment for BMI in NHS women,32 as well as Health Professionals Follow-Up Study (HPFS) men.33 The strong associations between Western pattern and inflammatory markers may explain the significant direct association of the Western dietary pattern with microalbuminuria."
Diet Pattern Indexes
We have previously identified 2 major diet patterns using the statistical procedure factor analysis (principal components).10 Briefly, foods from the FFQ first were classified into 38 food groups based on similar nutrient profiles or culinary use. The principle components procedure identifies diet patterns based on correlations between these food groups. We also used an orthogonal rotation procedure that results in uncorrelated factors or patterns.11 The factor score for each pattern was calculated by summing intakes of food groups weighted by their factor loadings.12 Factor scores were standardized to have a mean of 0 and standard deviation of 1. Scores reflect how closely a participant's diet resembles each identified pattern, with higher scores representing closer resemblance.
Each woman received a factor score for each identified pattern. The first identified factor, which we called the prudent pattern, is characterized by higher intake of fruits, vegetables, whole grains, fish, and poultry. The second factor, which we called the Western pattern, is characterized by higher intake of processed and red meats, refined grains, sweets, and desserts. Factor scores generated using this approach are not correlated with each other. Factor analysis was conducted using SAS PROC FACTOR (SAS Institute Inc, www.sas.com).13
We also constructed the DASH score as previously detailed14, 15 (range, 8-40 points) based on food and nutrients emphasized or minimized in the DASH diet16 focusing on 8 components: high intake of fruits, vegetables, nuts, legumes, low-fat dairy products, and whole grains and low intake of sodium, sweetened beverages, and red and processed meats.
Of note, 3 independent dietary patterns were derived based on a large number of correlated food items, which were aggregated into a small number of conceptually meaningful food patterns. Each individual receives a score for each pattern. There is only minor overlap between the Western and prudent patterns because we used an orthogonal rotation algorithm to derive the patterns (eg, correlations between them are close to zero).
Julie Lin, MD, MPH,1,2 Teresa T. Fung, SD, RD,3 Frank B. Hu, MD, PhD,1,4,5 and Gary C. Curhan, MD, ScD1,2,4
From the 1Channing Laboratory and 2Renal Division, Depart- ment of Medicine, Brigham and Women's Hospital, Harvard Medical School; 3Department of Nutrition, Simmons College; and Departments of 4Epidemiology and 5Nutrition, Harvard School of Public Health, Boston, MA.
Address correspondence to Julie Lin, MD, MPH, Renal Divi- sion, MRB-4, Brigham and Women's Hospital, 75 Francis St, Boston, MA 02115. E-mail: jlin11@partners.org
ABSTRACT
Background: Dietary patterns have been linked to such chronic diseases as cardiovascular disease, but sparse data currently are available for associations between dietary patterns and microalbuminuria or kidney function decline.
Study Design: Subgroup analysis from a prospective observational cohort study.
Setting & Participants: Female participants in the Nurses' Health Study who had dietary pattern data from food frequency questionnaires returned in 1984, 1986, 1990, 1994, and 1998 and urinary albumin-creatinine ratios from 2000 (n = 3,121); estimated glomerular filtration rate (eGFR) change between 1989 and 2000 was available for 3,071.
Predictor: Prudent (higher intake of fruits, vegetables, legumes, fish, poultry, and whole grains), Western (higher intake of red and processed meats, saturated fats, and sweets), and Dietary Approach to Stop Hypertension (DASH)-style dietary patterns (also greater intake of vegetables, fruits, and whole grains).
Outcomes & Measurements: Microalbuminuria (albumin-creatinine ratio, 25-354 μg/mg) in 2000 and change in kidney function using eGFR between 1989 and 2000.
Results: After multivariable adjustment, the highest quartile of Western pattern score compared with the lowest quartile was associated directly with microalbuminuria (OR, 2.17; 95% CI, 1.18-3.66; P for trend = 0.01) and rapid eGFR decline ≥3 mL/min/1.73 m2/y (OR, 1.77; 95% CI, 1.03-3.03). Women in the top quartile of the DASH score had decreased risk of rapid eGFR decline (OR, 0.55; 95% CI, 0.38-0.80), but no association with microalbuminuria. These associations did not vary by diabetes status. The prudent dietary pattern was not associated with microalbuminuria or eGFR decline.
Limitations: Study cohort included primarily older white women and generalizability of results would benefit from validation in nonwhites and men.
Conclusions: A Western dietary pattern is associated with a significantly increased odds of microalbuminuria and rapid kidney function decrease, whereas a DASH-style dietary pattern may be protective against rapid eGFR decline.
The presence of microalbuminuria and moderately decreased kidney filtration function are powerful predictors of cardiovascular disease1, 2, 3 and mortality,3, 4 but there are limited data about how diet, an important modifiable risk factor, might be associated with microalbuminuria or kidney function decrease. In particular, the influence of dietary patterns over time on the kidney is not well defined. Whereas traditional nutritional epidemiology has focused on individual nutrients or foods, perhaps their additive or interactive influence may be observed better when overall diet patterns are considered for incident chronic diseases. In addition to the ability to capture potential synergy between foods and nutrients, dietary patterns also may allow for easier translation into practical dietary advice because people eat many different foods in combination.5 Furthermore, classifying individuals according to their eating pattern can yield a larger contrast between exposure groups than analyses based on multiple single nutrients or foods, which can be influenced by collinearity.
One previously published study analyzed dietary patterns and albuminuria. The Multiethnic Study of Atherosclerosis (MESA) Study reported that a diet pattern rich in whole grains, fruit, and low-fat dairy foods was associated with lower albumin-creatinine ratios (ACRs).6 We therefore investigated the associations between dietary patterns and the presence of microalbuminuria or estimated glomerular filtration rate (eGFR) decline in 3,121 women participating in the Nurses' Health Study (NHS). We hypothesized that healthier eating patterns, measured using the prudent or DASH (Dietary Approach to Hypertension)-style dietary patterns, would be associated inversely, whereas the Western dietary pattern would be associated directly with microalbuminuria and eGFR decline.
Study Design
The NHS was initiated in 1976 with the enrollment of 121,700 US female nurses aged 30-55 years. This cohort is followed up through mailed biennial questionnaires related to lifestyle factors and health outcomes. Between 1989 and 1990, a total of 32,826 participants provided blood samples that were shipped on ice by overnight delivery and stored at -130°C as previously described.7 In 2000, a total of 18,720 of these participants submitted second blood and spot urine specimens. Participants who did and did not return blood samples were similar in terms of demographics and lifestyle characteristics.
The NHS women in this investigation were participants in substudies of analgesic use and kidney function8 or type 2 diabetes and kidney function. Women in the analgesic study had submitted plasma in 1989 and 2000 and were sent supplemental questionnaires to obtain detailed information regarding lifetime analgesic use. In total, 3,876 women returned the analgesic questionnaires. There were 2,712 women selected, with oversampling of those from the highest levels of lifetime analgesic consumption. For the type 2 diabetes substudy, we included 674 women who had submitted biological samples and had reported a diagnosis of diabetes that was confirmed using a diabetes supplemental questionnaire. The total number of women with diabetes was 694.
We included women who had cumulative average dietary pattern data available and who submitted a urine specimen in 2000 (n = 3,121; Fig 1). Most of these women (n = 3,071) also had plasma creatinine measured in samples collected in 1989 and 2000, which allowed us to examine eGFR change over 11 years.
Results
Study Participants and Dietary Pattern Assessment
Characteristics of these 3,121 women in 2000 are listed in Table 1, Table 2, Table 3. Median age was 67 years, 97% were white, 54% had hypertension, and 23% had diabetes. The Western and prudent dietary patterns had a weak but statistically significant inverse correlation (r = -0.07; P < 0.001). DASH score correlated directly with the prudent pattern (r = 0.76; P < 0.001) and inversely with the Western pattern (r = -0.30; P < 0.001). Cumulative average dietary pattern scores highly correlated comparing 1990 with 1998 values (all r > 0.94; P < 0.001), suggesting that dietary patterns were relatively unchanged in these women over time. Participant characteristics stratified by quartiles of dietary pattern scores are listed in Table 1, Table 2, Table 3.
Microalbuminuria
The 177 women (5.7%) who met the criterion for microalbuminuria (ACR, 25-355 μg/mg) were more likely to be older and have hypertension, diabetes, cardiovascular disease, higher BMI, and lower activity levels (Table 1, Table 2, Table 3). In age- and energy-adjusted models, the Western pattern diet was associated directly with microalbuminuria (odds ratio [OR], 3.55 [95% confidence interval (CI), 2.03-6.20] for the fourth vs first quartile), whereas DASH score was associated inversely with microalbuminuria (OR, 0.53 [95% CI, 0.33-0.84] for the fourth vs first quartile). There was no association between the prudent diet pattern and microalbuminuria. After multivariable adjustment, the association between Western diet and microalbuminuria remained significant (OR, 2.17 [95% CI, 1.18-3.96] for the fourth vs first quartile), but not the DASH-style diet (Table 4). BMI, diabetes, and physical activity level appeared to be the major confounders in the association between dietary patterns and microalbuminuria.
Stratifying analyses by diabetes status also did not meaningfully change results. When the outcome of ACR ≥25 μg/mg was examined, results also were not meaningfully changed.
eGFR Decline
There were 346 (11.3%) women who experienced an eGFR decline ≥30% between 1989 and 2000; this reflected a median increase in plasma creatinine level of 0.33 mg/dL. There were 230 (7.5%) women with eGFR decline ≥3 mL/min/1.73 m2/y, representing a median eGFR decline rate of 3.8 mL/min/1.73 m2/y and a median increase in plasma creatinine level of 0.34 mg/dL.
There were no significant associations between the prudent pattern and eGFR decline. After multivariable adjustment, the Western pattern was not significantly associated with eGFR decline ≥30% (Table 5). DASH score maintained a significant inverse association with eGFR decline ≥30% after adjustment (OR, 0.55 [95% CI, 0.38-0.80] comparing top with bottom quartiles). Results were not meaningfully different when adjusted for analgesic medication use, high cholesterol level or lipid-lowering medication use, or diabetes duration (Table 3). These associations for Western diet and DASH score did not vary by baseline eGFR <80 mL/min/1.73 m2 or diabetes status because all P values for interaction terms were nonsignificant. Results using ≥3 mL/min/1.73 m2/y eGFR decline were virtually identical except that the highest quartile of the Western pattern remained statistically significantly associated after multivariable adjustment (OR, 1.77; 95% CI, 1.03-3.03).
Our results for kidney function decrease were unchanged when the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation was used to estimate GFR27 or if change in weight or BMI was included as a covariate in the adjusted models.
Discussion
Our data suggest that dietary patterns are associated with microalbuminuria and kidney function decrease in middle-aged and older women. Women in the highest quartile of the Western pattern had a significant 2-fold increased odds of having microalbuminuria and experiencing more rapid eGFR decline ≥3 mL/min/1.73 m2/y. Moreover, a DASH-style pattern appears to decline risk by >40% for eGFR decline ≥30% over 11 years.
We previously reported that higher dietary intake of animal fat was associated with the presence of microalbuminuria, whereas higher sodium intake was associated directly and higher beta-carotene intake was associated inversely with faster eGFR decline over 11 years.28 The present study provides additional information regarding decline in kidney function and dietary patterns that may be interpreted more easily by the general public.
The lack of association with the prudent pattern with renal outcomes despite its correlation with the DASH pattern may be due to the different weights given to food groups used to derive each score. Our results suggest that DASH score may better reflect food groups most relevant to microalbuminuria and eGFR decline. Of note, we do not believe the DASH-style diet is merely a surrogate for low sodium intake because we did not find significant associations of DASH scores with 24-hour urinary sodium excretion in a subset of ~1,200 NHS 1 women with these data.29 Although dietary protein (particularly red meat) intake may potentially affect plasma creatinine concentrations, we previously have ascertained that all nutrient intake, including total and subtypes of protein, varied by ≤16% over time in this cohort of women.28 Therefore, changes in dietary protein intake are unlikely to explain change in eGFR.
We hypothesize that inflammation might be one possible pathophysiologic link between dietary patterns and microalbuminuria. A number of studies have reported significant direct associations between markers of inflammation and higher albuminuria. For example, in a recent publication from the National Health and Nutrition Examination Surveys 1999-2004, each 1-mg/dL increase in C-reactive protein (CRP) level was associated independently with a 1.02 (95% CI, 1.01-1.02; P = 0.0003) OR for the presence of microalbuminuria in this large nationally representative cohort.30 Furthermore, the highest tertile of ICAM-1 (inter-cellular adhesion molecule 1), a vascular endothelial transmembrane glycoprotein upregulated by inflammation, also previously has been associated independently with the development of incident sustained microalbuminuria (OR, 1.67; P for trend = 0.03) in patient with type 1 diabetes.31
Previous work on dietary patterns and inflammation reported that the Western diet pattern showed significant direct correlations between CRP, ICAM-1, and VCAM-1 (vascular cell adhesion molecule 1) levels in multivariable models that included adjustment for BMI in NHS women,32 as well as Health Professionals Follow-Up Study (HPFS) men.33 The strong associations between Western pattern and inflammatory markers may explain the significant direct association of the Western dietary pattern with microalbuminuria. In these previous studies, the prudent pattern was not associated with inflammatory marker levels after multivariable adjustment, which may be consistent with the lack of association between the prudent pattern and microalbuminuria. No data currently appear to be available for DASH score and markers of inflammation.
An investigation in the MESA that included almost 5,000 ethnically diverse men and women similarly has reported that a dietary pattern rich in whole grains, fruit, and low-fat dairy foods was associated with lower urinary ACR (20% lower ACR across quintiles, P for trend = 0.004), whereas nondairy animal-based food intake was associated directly (11% higher ACR across quintiles, P for trend = 0.03).6 The MESA cohort also has reported that diets high in whole grains, fruits or vegetables, and fish are associated inversely with markers of inflammation, including CRP and soluble ICAM-1 levels, whereas a diet pattern high in fats and processed meats was associated directly with markers of inflammation, including CRP.34 Data from other cohorts provide external validation for our findings regarding diet patterns, inflammation, and albuminuria in the NHS cohort.
There are no published data for dietary patterns and eGFR decline, but recent investigations have suggested that markers of inflammation,35 including CRP,36 are associated with faster eGFR decline. Therefore, because inflammatory biomarkers have been proposed to be potential mediators for associations observed between diet and cardiovascular disease,37 we propose that inflammation also may be a factor in associations between diet and eGFR decline.
Notable strengths of this investigation include the relatively large number of women with data for both albuminuria and eGFR decline. Change in eGFR was assessed during an 11-year period, and repeated measures of diet intake over 14 years were performed. The substantial numbers of covariates, most of which have been validated extensively in this large and well-established longitudinal cohort, are additional assets in these analyses.
Limitations of this study include the predominant white population of older women; therefore, results may not necessarily be generalizable to men or nonwhite populations. However, similar results in the analysis of dietary patterns and albuminuria in the ethnically diverse MESA cohort would suggest that the associations may not vary substantially by race or ethnicity.6 In addition, no data for change in urinary ACR were available in our participants, and albuminuria analyses are cross-sectional. Markers of inflammation are not available in this subcohort of women. The presence of residual confounding also is possible, as in any observational study. Measurements of glycemic control to define glucose intolerance or prediabetes were not available for most of these women, although we conservatively considered a participant with a diagnosis of diabetes up to 10 years after the initial blood draw to address this issue. The possibility of survival bias is present because women who died before 2000 would not have been included in this study; however, we would expect this to bias results toward the null, whereas statistically significant associations between dietary patterns and microalbuminuria and eGFR decline were observed.
In conclusion, a Western pattern diet was associated with a 2-fold higher OR for microalbuminuria and increased risk of rapid eGFR decline (≥3 mL/min/1.73 m2/y). A DASH-style diet was associated with an almost 50% declined risk of eGFR decline. Therefore, diets higher in fruits, vegetables, and whole grains, but lower in meat and sweets, may be protective against eGFR decline. Future directions of interest include validation of these findings in other cohorts and examining how individual foods might influence microalbuminuria and eGFR decline.
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